AGUNABU
UMUELECHI BIAFRA ULTIMATE DIATRIBE ON THE
POLITICS OF HIV-AIDS
Dr Jideofo Kenechukwu Danmbaezue,
D.Sc.
Can someone explain
why the entries in the 1988 version of Microsoft Encarta encyclopaedia on
Acquired Immunodeficiency Syndrome and that of the 2004 version are very
different? Why was the detailed history of the development of the virus absent
in the latter version? If there is no ulterior motive for this discrepancy,
then let someone interpret the etymological meanings of the words: ‘isolated',
‘discovered' and ‘invented' in common day usage of the words! What does each
imply?
BY THE ANIMATOR OF HAFANI RESEARCH CONSORTIUM @ UNIVERSITY
OF NIGERIA , ENUGU
Acquired Immune Deficiency Syndrome (AIDS), specific group of diseases or conditions that result from
suppression of the immune system related to
infection with the human immunodeficiency virus
(HIV). A person infected with HIV gradually loses immune function along with
certain immune cells called CD4
T-lymphocytes or CD4 T-cells, causing the infected person to become vulnerable
to pneumonia, fungus
infections, and other common ailments. With the loss of immune function,
a clinical syndrome (a group of
various illnesses that together characterize a disease) develops over time and
eventually results in death due to opportunistic
infections
(infections by organisms that do not normally cause disease except in people
whose immune systems have been greatly weakened) or cancers.
In the early 1980s deaths by
opportunistic infections, previously observed mainly in organ transplant recipients receiving therapy to suppress
their immune responses, were recognized in otherwise healthy homosexual men. In 1983 French cancer specialist
Luc Montagnier and scientists at the Pasteur Institute in Paris
Infection
with HIV does not necessarily mean that a person has AIDS, although people who
are HIV-positive are often mistakenly said to have AIDS. In fact, a person can
remain HIV-positive for more than ten years without developing any of the
clinical illnesses that define and constitute a diagnosis of AIDS. In 1996 an
estimated 22.6 million people worldwide were living with HIV or AIDS-21.8
million adults and 830,000 children. The World
Health Organization (WHO) estimates that between 1981, when the first
AIDS cases were reported, and the end of 1996, more than 8.4 million adults and
children had developed AIDS. In this same period there were 6.4 million deaths
worldwide from AIDS or HIV. About 360,000 of these deaths occurred in the United States
Clinical Progression of AIDS
The
progression from the point of HIV infection to the clinical diseases that define AIDS may take six to ten years
or more. This progression can be monitored using surrogate markers (laboratory data that correspond to the various
stages of disease progression) or clinical
endpoints (illnesses associated with more advanced disease). Surrogate
markers for the various stages of HIV infection include the declining number of
CD4 T-cells, the major type of white
blood cell lost because of HIV infection. In general, the lower the infected
person's CD4 T-cell count, the weaker
the person's immune system and the more advanced the disease state. In 1996 it
became evident that the actual amount of HIV in a person's blood-the so-called viral burden-could be used to
predict the progression to AIDS, regardless of a person's CD4 T-cell count. With advancing technology, viral burden
determinations are quickly becoming a standard means of patient testing.
An
infected person's immune response to the virus-that is, the person's ability to
produce antibodies against HIV-can also be
used to determine the progression of AIDS; however, this surrogate marker is
less precise during more advanced stages of AIDS because of the overall loss of
immune function.
Within
one to three weeks after infection with HIV, most people experience nonspecific
flulike symptoms such as fever, headache, skin rash, tender lymph nodes, and a
vague feeling of discomfort. These symptoms last about one to two weeks. During
this phase, known as the acute retroviral syndrome phase, HIV reproduces to
very high concentrations in the blood, mutates (changes its genetic nature)
frequently, circulates through the blood, and establishes infections throughout
the body, especially in the lymphoid organs. The infected person's CD4 T-cell count falls briefly but then
returns to near normal levels as the person's immune system responds to the
infection. Individuals are thought to be highly infectious during this phase.
Following
the acute retroviral syndrome phase, infected individuals enter a prolonged asymptomatic phase-a symptom-free phase
that can last ten years or more. Persons with HIV remain in good health during
this period, with levels of CD4
T-cells ranging from low to normal (500 to 750 cells per cubic mm of blood).
Nevertheless, HIV continues to replicate during the asymptomatic phase, causing
progressive destruction of the immune system.
Eventually,
the immune system weakens to the point that the person enters the early symptomatic phase. This phase can
last from a few months to several years and is characterized by rapidly falling
levels of CD4 T-cells (500 to 200
cells per cubic mm of blood) and opportunistic infections that are not life
threatening.
Following
the early symptomatic phase, the infected person experiences the extensive
immune destruction and serious illness that characterize the late symptomatic phase. This phase can
also last from a few months to years, and the affected individual may have CD4 T-cell levels below 200 per cubic mm
of blood along with certain opportunistic infections that define AIDS. A
wasting syndrome of progressive weight loss and debilitating fatigue occurs in
a large proportion of people in this stage. The immune system is in a state of
severe failure. The person eventually enters the advanced AIDS phase, in which CD4
T-cell numbers are below 50 per cubic mm of blood. Death due to severe
life-threatening opportunistic infections and cancers usually occurs within one
to two years.
Opportunistic Illnesses
Death
from AIDS is generally due not to HIV infection itself, but to opportunistic
infections that occur when the immune system can no longer protect the body
against agents normally found in the environment. The appearance of any one of
more than 25 different opportunistic infections, called AIDS-defining
illnesses, along with a CD4 T-cell
count of less than 200 cells per cubic millimeter of blood provides the
clinical diagnosis of AIDS in HIV-infected individuals.
The
most common opportunistic infection seen in AIDS is Pneumocystis carinii pneumonia (PCP), which is caused by a fungus
that normally exists in the airways of all people. Bacterial pneumonia and tuberculosis are also commonly associated with
AIDS. In the late symptomatic phase of AIDS, bacterial infection by Mycobacterium avium can cause fever,
weight loss, anemia, and diarrhea. Additional bacterial infections of the
gastrointestinal tract commonly cause diarrhea, weight loss, anorexia (loss of
appetite), and fever. Also, during advanced AIDS, diseases caused by protozoal
parasites, especially toxoplasmosis of the
nervous system, are common.
In
addition to PCP, people with AIDS often develop other fungal infections. Thrush, an infection of the mouth by the fungus Candida albicans, is common in the early
symptomatic phase of AIDS. Other infectious fungi include species of the genus Cryptococcus, a major cause of meningitis in up to 13 percent of people with AIDS.
Also, infection by the fungus Histoplasma
capsulatum affects up to 10 percent of people with AIDS, causing general
weight loss, fever, and respiratory complications or severe central nervous
system complications if the infection reaches the brain.
Viral
opportunistic infections, especially with members of the herpes virus family, are common in people with
AIDS. One herpes family member, cytomegalovirus (CMV), infects the retina of
the eye and can result in blindness. Another
herpes virus, Epstein-Barr virus (EBV), may result in a cancerous
transformation of blood cells. Infections with herpes simplex virus (HSV) types
1 and 2 are also common and result in progressive sores around the mouth and
anus.
Many
people with AIDS develop cancers, the most common types being B-cell lymphoma
and Kaposi's sarcoma (KS). Kaposi's sarcoma-a cancer of blood
vessels that results in purple lesions on the skin that can spread to internal
organs and cause death-occurs mainly in homosexual and bisexual
men. Although the cause of KS is unknown, a link between KS and a new type of
herpes virus was discovered in 1994.
Human Immunodeficiency Virus (HIV)
The
causative agent of AIDS is HIV, a human retrovirus. Researchers have known
since 1984 that HIV enters human cells by binding with a receptor protein known
as CD4, located on human immune-cell
surfaces. HIV carries on its surface a viral protein
known as gp120, which specifically
recognizes and binds to the CD4 protein molecules on the outer surface of human
immune cells. However, in 1984 researchers found that CD4 by itself was not sufficient for HIV infection to take place.
Some other unknown factor, found only in human cells, was also required. After
much research, in 1996 scientists discovered that HIV must also bind to chemokine receptors, small proteins also
found on the surface of human immune cells, to enter the cells. The first
chemokine receptor linked to HIV entry was CXCR4
(originally called fusin), which is bound by HIV strains that dominate during
the latter stages of the disease. Researchers then determined that another
chemokine receptor, CCR5, bound HIV
strains that dominate in the early stages of the disease. Researchers are
continuously discovering more chemokine receptors.
Any
human cell that has the correct binding molecules on its surface is a potential
target for HIV infection. However, it is the specific class of human white
blood cells called CD4 T-cells that
are most affected by HIV because these cells have high concentrations of the CD4 molecule on their outer surfaces.
HIV replication in CD4 T-cells can
kill the cells directly; however, the cells also may be killed or rendered dysfunctional
by indirect means without ever having been infected with HIV. CD4 T-cells are critical in the normal
immune system because they help other types of immune cells respond to invading
organisms. As CD4 T-cells are
specifically killed during HIV infection, no help is available for immune
responses. General immune system failure results, permitting the opportunistic
infections and cancers that characterize clinical AIDS.
Although
it is generally agreed that HIV is the virus that causes AIDS and that HIV
replication can directly kill CD4
T-cells, the large variation among individuals in the amount of time between
infection with HIV and a diagnosis of AIDS has led to speculation that other cofactors-that is, factors acting along
with HIV-may influence the course of disease. The exact nature of these
cofactors is uncertain-it is believed that they may include genetic,
immunologic, and environmental factors or other diseases. However, it is clear
that HIV must be present for the development of AIDS.
Modes of Transmission
HIV is
spread through the exchange of body fluids, primarily semen, blood, and blood
products. It is most commonly spread by sexual contact with an infected person.
The virus is present in the sexual secretions of infected men and women and
gains access to the bloodstream of the uninfected person by way of small
abrasions that may occur as a consequence of sexual intercourse.
HIV is
also spread by any sharing of needles or syringes that results in direct
exposure to the blood of an infected individual. This method of exposure occurs
most commonly among people abusing intravenous (IV) drugs (drugs injected into
the veins).
HIV
transmission through blood transfusions or use of blood-clotting factors is now
extremely rare because of extensive screening of the blood supply; it is
estimated that undetected HIV is present in fewer than 1 in 450,000 to 600,000
units of blood.
HIV
can be transmitted from an infected mother to her baby, either before or during
childbirth, or through breast-feeding. Although only about 25 to 35 percent of
babies born to HIV-infected mothers worldwide actually become infected, this
mode of transmission accounts for 90 percent of all cases of AIDS in children.
In addition, even uninfected children born to HIV-infected mothers have an
incidence of heart problems 12 times that of children in the general
population.
In the
health care setting, workers have been infected with HIV after being stuck with
needles containing HIV-infected blood or, less frequently, after infected blood
contacts the worker's open cut or splashes into a mucous membrane (for example,
the eyes or the inside of the nose). There has been only one demonstrated
instance of patients being infected by a health-care worker; this involved HIV
transmission from an infected dentist to six patients. In general, infected
health-care workers pose no risk to their patients. There is also no risk of
contracting HIV infection while donating blood.
The
routes of HIV transmission are well known, but unfounded fear continues
concerning the potential for transmission by other means, such as casual
contact in a household, school, workplace, or food-service setting. No
scientific evidence to support any of these fears has been found. HIV does not
survive well when exposed to the environment. Drying of HIV-infected human
blood or other body fluids reduces the theoretical risk of environmental
transmission to essentially zero. Additionally, HIV is unable to reproduce
outside its living host; therefore, it does not spread or maintain
infectiousness outside its host.
No
cases of HIV transmission through the air, by casual contact, or even by
kissing an infected individual have been documented. Researchers have recently
identified a protein in saliva, known as secretory leukocyte protease inhibitor
(SLPI), that prevents HIV from infecting white blood cells. However, practices
that increase the likelihood of contact with the blood of an infected
individual, such as open-mouth kissing or sharing toothbrushes or razors,
should be avoided. There is also no known risk of HIV transmission to
coworkers, clients, or consumers from contact in food-service establishments.
Studies
have shown no evidence of HIV transmission through insects-even in areas where
there are many cases of AIDS and large populations of insects such as mosquitoes. HIV lives for only a short time inside
an insect and does not reproduce. Thus, even if the virus enters a mosquito or
another sucking or biting insect, the insect does not become infected and
cannot transmit HIV to the next human it feeds on or bites.
Occurrence
The
nature of the AIDS epidemic is constantly evolving. In the United States United States
Of the
more than 580,000 AIDS cases reported in the United States between 1981 and
1996, about 46 percent have been in Caucasians, 35 percent in blacks, 18
percent in Hispanics, and 1 percent in Asians. Males make up about 84 percent
of these cases and females 15 percent. Children account for the remaining 1
percent of AIDS cases. Women and children constitute one of the fastest-growing
groups of people with AIDS. Through December 1996, 52 documented cases and 111
possible cases of occupational transmission of AIDS/HIV infection had been
reported in health-care workers. In 1994 and 1995 AIDS was the leading cause of
death among Americans aged 25 to 44 years, the leading cause of death for
American men of the same age group, and the third leading cause of death among
American women in that same age group.
On a
global scale, the AIDS epidemic is rapidly expanding. Of the estimated 22.6
million people worldwide living with HIV or AIDS in 1996, about 62 percent were
living in sub-Saharan Africa, 23 percent in southern and eastern Asia and the
Pacific , 6 percent in Latin America, 5 percent in North America and the
Caribbean, and 2 percent in Europe and Central Asia. In Asia and Africa , most people contract the disease through
heterosexual contact.
The
major strain of HIV in the United States ,
Europe, and central Africa is known as HIV-1.
In western Africa , AIDS is also caused by
HIV-2, a strain of HIV closely related to HIV-1. Other distantly related
strains of HIV-1 have been identified in various areas of the world. Although
some of these strains cannot be detected with current blood-screening methods,
there is little risk of these viruses spreading to the United States Africa is rare. Only 64 cases of HIV-2
have been documented in the United States ,
and transmission in these cases was linked directly to western Africa .
Detection and Diagnosis
Although
AIDS has been tracked since 1981, the identification of HIV as the causative
agent was not made until 1983. In 1985 the first blood test for HIV, developed
by the research group led by Robert Gallo, was approved for use in blood banks.
This test can detect whether a person's blood contains antibodies against HIV,
an indication of exposure to the virus. However, for about four to eight weeks
after exposure to HIV, an individual will continue to test negative for HIV
infection because the immune system has not had enough time to make antibodies
against HIV. In 1996 an additional blood test was approved for use in blood
banks. This test can detect HIV antigens-proteins produced by the virus itself.
The test can thus identify HIV even before the donor's immune system has had a
chance to make antibodies. An estimated 50 million blood samples are tested
each year in the United
States
The Centers for Disease Control and Prevention (CDC) in
Atlanta, Georgia, has established an authoritative definition for the diagnosis
of AIDS: In an HIV-positive individual, the CD4
T-cell count must be below 200 cells per cubic mm of blood, or there must be
the clinical appearance of an initial AIDS-defining opportunistic infection,
such as PCP (Pneumocystis carinii
pneumonia), oral candidiasis (thrush), pulmonary tuberculosis, or invasive
cervical carcinoma (cancer of the cervix in women).
Treatment
Antiviral
drugs that attack HIV exploit vulnerable spots in the viral replication cycle.
One target is the process of reverse transcription-that is, the conversion of
the viral ribonucleic acid (RNA) into deoxyribonucleic acid (DNA)-that HIV must undergo
to be infectious. Reverse transcription is a process unique to retroviruses and
is performed by the viral enzyme reverse
transcriptase (RT). One class of anti-HIV drugs, known as nucleosides, are all
RT inhibitors. Five nucleosides are currently licensed by the U.S. Food and Drug Administration (FDA): zidovudine
(Retrovir, AZT), didanosine (Videx, ddI), zalcitabine (Hivid, ddC), stavudine
(Zerit, d4T), and lamivudine (Epivir, 3TC). These drugs work as DNA-chain
terminators. Because the drug appears to be a normal nucleotide base (the
building block of DNA), the RT enzyme mistakenly inserts the drug into the
growing viral DNA chain. Once the drug is inserted, no additional DNA bases can
be added, and therefore viral DNA synthesis is terminated.
Although
the nucleosides are more likely to interact with the viral RT enzyme, they also
can be incorporated by the enzyme responsible for normal cellular DNA synthesis
in the person receiving the drug, leading to toxicity (poisoning) and side
effects. Such drug incorporation is usually observed in rapidly dividing cell
types, such as the cells of the bone
marrow, spongy tissue filling the cavities within bones.
A
second problem is the emergence of drug-resistant forms of HIV in people
receiving these drugs. Studies on early treatment of HIV infection with AZT
have presented contradictory results as to whether such early treatment
prolongs life. Because HIV replicates rapidly and mutates frequently during the
earliest period of infection, an HIV-infected person carries many different
strains of HIV, some of which may be drug-resistant. The limited variety of HIV
in the early stage is thought to make it more susceptible to AZT and related
drugs.
Although
RT inhibitors were never considered a cure for HIV infection, it was hoped that
they would slow the progression of AIDS, and AZT has been shown effective in
reducing HIV transmission from pregnant women to their babies. However, the
clinical benefit of RT inhibitors when used alone has been largely
disappointing; they have extended the lives of people with AIDS by only about
six months. When taken in conjunction with other RT inhibitors, however, they have
been more effective. For example, AZT combined with lamivudine prevents the
AIDS virus from developing resistance to AZT even though the virus quickly
develops resistance to lamivudine. The combination also has been shown to boost
CD4 T-cell counts and to lower levels
of HIV in the blood. In November 1995 the FDA approved the combined use of AZT
and lamivudine for early treatment of AIDS.
RT
inhibitors are also effective when used with a new class of anti-HIV drugs
known as protease inhibitors,
approved by the FDA in December 1995. Protease inhibitors work by crippling a
key viral enzyme called protease, which is vital to the reproduction of HIV in
the later stages of its replication cycle.After HIV replicates-that is, makes copies of its own protein components-these
proteins must be cut to specific sizes before they can assemble into a mature
virus. Protease is responsible for trimming the new HIV proteins to their
required dimensions. When protease is blocked-or inhibited-the proteins are not
cut andthe defective HIV cannot infect new cells. The first protease inhibitor
drug, saquinavir (Invirase), was approved for use in combination with
nucleoside drugs such as AZT. In March 1996 two additional drugs, ritonavir
(Norvir) and indinavir (Crivaxin), were rapidly approved for use alone or in
combination with nucleosides. A fourth drug, nelfinavir (Viracept), was
approved by the FDA in March 1997 for both adult and child use. Ritonavir,
formerly allowed for adult use only, was also approved for adult and child use.
Preliminary
results from four American and European studies indicate that these drugs cause
dramatic increases in the number of CD4
T-cells and decreases in the amount of virus in the blood. These results are
about two to three times more powerful than those seen with the nucleoside
drugs. Researchers cautioned that new studies show also that HIV can quickly
develop resistance to these new drugs, at least when they are used alone.
However, researchers suspect that the resistance can be delayed when the agents
are combined with other anti-HIV drugs-for example, the nucleosides.
In
fact, the most effective treatment against HIV is now considered to be a
combinationof three drugs taken together-two nucleoside RT inhibitors and one
protease inhibitor. Although these drug combinations may cause severe side
effects (such as diarrhea, abdominal cramps, and anemia), when taken properly
they can reduce blood levels of the virus to undetectable levels. Each drug
must be taken according to specific guidelines, however, and one missed dose
can allow the virus to quickly mutate to a strain that resists the drugs.
These
drug combinations can also consist of two nucleoside RT inhibitors and one
non-nucleoside RT inhibitor, a new class of anti-HIV drug first recommended for
approval by the FDA in June 1996. These drugs work similarly to nucleoside RT
inhibitors in that they bind to the HIV reverse transcriptase enzyme. However,
they do not compete with other nucleosides for binding sites. The first drug of
this type to be developed was nevirapine (Viramune), which was appproved by the
FDA in April 1997. A second non-nucleoside RT inhibitor, delavirdine
(Rescriptin), is currently available only in test settings. Both drugs are
effective only when taken with nucleoside RT inhibitors; they should not be
used with protease inhibitors.
No matter which drug combination is
administered, researchers believe that the earlier a patient is treated for
HIV, the greater the chance that the treatment will be effective.
The
development of antiviral therapies for HIV is complex, and each new approach
and drug must be extensively evaluated for safety and effectiveness. The
general perception that this evaluation process causes unnecessary delays in
providing therapies spurred public demonstrations against the FDA. These
demonstrations have resulted in policy changes that make experimental drugs and
approaches more readily available to people with AIDS, even before the drugs or
approaches are approved. Although early availability of a drug entails the risk
that it may be used in people before its toxicity and side effects are fully
understood, many people with AIDS are willing to take this risk with the hope
that the drug may prove effective.
Effective
drug treatments are available to fight many AIDS-associated opportunistic
infections, and these treatments have provided clinical benefit and prolonged
survival for individuals with AIDS. Recent drug treatments for PCP have
dramatically decreased illness and death due to this opportunistic infection.
Antifungal drugs such as amphotericin B and fluconazole are effective against
AIDS-related fungal infections. The antiherpes drugs ganciclovir and foscarnet
are used to treat CMV retinitis and other herpes diseases. Because these
therapies require medical supervision and are often needed on an extended
basis, a network of community hospices (see
Hospital) has been established to provide
low-cost outpatient care for individuals with AIDS. Some hospices provide
shelter and compassionate support for people living with AIDS.
Gene therapy, an approach that
involves altering the genes of the infected person to help prevent the virus
from spreading to uninfected cells, might someday be used to treat HIV
infection. Gene therapy has been used in clinical trials to inhibit HIV by
introducing into cells a new gene that interferes with the viral regulatory
proteins. In other trials, gene therapy has been used to introduce a new gene
that protects the cells from becoming infected by HIV.
Efforts
also are under way to develop an effective immunization
that could be either protective,
preventing infection if an immunized person is exposed to HIV, or therapeutic, prolonging survival or
decreasing immune destruction in people already infected with HIV. The World
Health Organization (WHO) is currently sponsoring a large-scale trial of a
protective-vaccine candidate in areas of the world where the rate of HIV
infection is just beginning to rise dramatically. In 1996 the FDA for the first
time gave researchers in the United
States
With
the discovery in 1996 that HIV must bind to chemokine receptors as well as CD4 molecules, researchers also began to
develop laboratory chemokines that might block HIV from attaching to these
receptors and casing infection. Individuals who lack CCR5 receptors due to a genetic defect appear to be protected from
contracting the disease.
Prevention Efforts
Because
there is as yet no successful vaccination against HIV, prevention efforts have
focused mainly on educating the public about routes of HIV transmission and
about personal measures that reduce the risk of infection. The CDC has
established the National AIDS Clearinghouse, a hotline to disseminate
educational literature and current statistics on AIDS. Safe-sex campaigns
encourage sexual abstinence or monogamy (sexual relations with only one
partner) and the use of latex condoms to provide a protective barrier during
sexual intercourse (see Birth Control). Needle-exchange programs have been
implemented to reduce needle sharing and consequent HIV transmission among IV
drug abusers. The U.S.
Social Issues
Many
people consider HIV infection and AIDS to be completely preventable because the
routes of HIV transmission are so well known. To completely prevent
transmission, however, dramatic changes in sexual behavior and drug dependence
would have to occur throughout the world. Furthermore, prevention efforts that
promote sexual awareness through open discussion and condom distribution in
public schools have been opposed because of the fear that these efforts may
encourage sexual activity. Similarly, needle exchange programs have been
criticized as promoting drug abuse. Prevention programs that identify
HIV-infected individuals and notify their sexual partners, as well as programs
that promote HIV testing at the time of marriage or pregnancy, have been
criticized for invading personal privacy.
Efforts
aimed at public awareness have been propelled by community-based organizations
such as Project Inform and Act-Up, which provide current information to HIV-infected
individuals and to individuals at risk for infection. Public figures and
celebrities who are themselves HIV infected or who have died from
AIDS-including American basketball player Magic
Johnson, American actor Rock Hudson, American diver Greg Louganis, and American tennis player Arthur Ashe-have personalized the disease of AIDS
and thereby helped society come to terms with the enormity of the epidemic. As
a memorial to people who have died from AIDS, especially in the early years of
the epidemic, friends and families of AIDS victims stitched together a giant
quilt in which each panel of the quilt was dedicated to the memory of an
individual who died from AIDS. This quilt has traveled on display from
community to community to promote AIDS awareness.
The U.S.
The
lack of effective vaccines and antiviral drugs for AIDS has spurred speculation
that the funding for AIDS research is insufficient. Although the actual amount
of government funding for AIDS research is large, most of these funds are used
for expensive clinical studies to evaluate new drugs. Many scientists believe
that not enough is known about the basic biology of HIV and recommend shifting
the emphasis of AIDS research to basic research that could ultimately result in
more effective medicines.
Contributed By:
What you have read
so far was the original entry in the first ever edition/version of the
Microsoft Encarta Encyclopaedia.
Why then did the authors
reorganize the text and omit the underlined sentences or sections, which are
very vital to the proper understanding of how the retrovirus was
"isolated", a terminology they used thrice?
What is ISOLATE and
why was it introduced instead of using DISCOVERED or INVENT they were using
earlier.
Now, we read what is
now in Microsoft ® Encarta ® Encyclopaedia 2004.
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I
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INTRODUCTION
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Acquired Immunodeficiency Syndrome (AIDS),
human viral disease that ravages the immune system, undermining the body's
ability to defend itself from infection and disease. Caused by the human
immunodeficiency virus (HIV), AIDS leaves an infected person vulnerable to
opportunistic infections. Such infections are harmless in healthy people, but
in those whose immune systems have been greatly weakened, they can prove fatal.
Although there is no cure for AIDS, new drugs are available that can prolong
the life spans and improve the quality of life of infected people.
Infection with HIV does not necessarily mean that a person has AIDS. Some
people who have HIV infection may not develop any of the clinical illnesses
that define the full-blown disease of AIDS for ten years or more. Physicians
prefer to use the term AIDS for cases
where a person has reached the final, life-threatening stage of HIV infection.
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II
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PREVALENCE
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AIDS was first identified in 1981 among homosexual men and intravenous drug
users in New York and California United States , evidence
of AIDS epidemics grew among heterosexual men, women, and children in
sub-Saharan Africa . AIDS quickly developed
into a worldwide epidemic, affecting virtually every nation. By 2002 an
estimated 38.6 million adults and 3.2 million children worldwide were living
with HIV infection or AIDS. The World Health Organization (WHO), a specialized
agency of the United Nations (UN), estimates that from 1981 to the end of 2002
about 20 million people died as a result of AIDS. About 4.5 million of those
who died were children under the age of 15.
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A
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In the United States U.S. Canada
The incidence of new cases of HIV infections and AIDS deaths has
significantly decreased in Canada
and the United States United States United States United
States
|
B
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In western Europe the first cases of AIDS were detected in the early
1980s, and by the late 1990s, at least 30,000 new HIV infections occurred each
year. In 2002 about 570,000 western Europeans were HIV positive, and 25 percent
of these cases were women. Before the dissolution of the Union of Soviet
Socialist Republics (USSR) in 1991, eastern Europe reported few HIV cases. But
since 1995, HIV infection has spread rapidly in cities of several eastern
European countries, including Ukraine ,
Belarus , and Moldova
|
C
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Developing Nations
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While cases of AIDS have been reported in every nation of the world, the
disease affects some countries more than others. More than 95 percent of all
HIV-infected people live in the developing world. In these areas, the disease
has sapped the populations of young men and women who form the foundation of
the labor force. Most die while in the peak of their reproductive years.
Moreover, the epidemic has overwhelmed health-care systems, increased the
number of orphans, and caused life expectancy rates to plummet. These problems
have reached crisis proportions in some parts of the world already burdened by
war, political upheaval, or unrelenting poverty.
Nowhere is this better demonstrated than in sub-Saharan Africa ,
where the number of AIDS cases far exceeds that of all other geographic
regions. Of the estimated 14,000 HIV infections that occur each day worldwide,
about half of these infections occur in sub-Saharan Africa .
About 70 percent of all people infected with HIV live in this region. In some
countries in the southern part of the continent, including Botswana , Lesotho ,
Swaziland , and Zimbabwe
In Asia and the Pacific
Islands China
and India , the world's two
most populous countries, cases of HIV infection in this region may surge up to
25 million cases by the year 2010, dwarfing the problems seen in sub-Saharan Africa .
In 2002 the Chinese government reported that China Yunnan , in southern China , and Xinjiang, in northwestern China China China China
In Latin America and the Caribbean region nearly 1.7 million people have
been diagnosed with HIV infection or AIDS, twice the incidence in the United States and Canada Brazil ,
Mexico , Colombia , and Argentina
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III
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CAUSE
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AIDS is the final stage of a chronic infection with the human
immunodeficiency virus. There are two types of this virus: HIV-1, which is the
primary cause of AIDS worldwide, and HIV-2, found mostly in West
Africa . On its surface, HIV carries a protein structure that
recognizes and binds only with a specific structure found on the outer surface
of certain cells. HIV attacks any cell that has this binding structure.
However, white blood cells of the immune system known as T cells, which
orchestrate a wide variety of disease-fighting mechanisms, are especially
vulnerable to HIV attack. Particularly vulnerable are certain T cells known as
CD4 cells. When HIV infects a CD4 cell, it commandeers the genetic tools within
the cell to manufacture new HIV virus. The newly formed HIV virus then leaves
the cell, destroying the CD4 cell in the process. No existing medical treatment
can completely eradicate HIV from the body once it has integrated into human
cells.
The loss of CD4 cells endangers health because these immune cells help
other types of immune cells respond to invading organisms. The average healthy
person has over 1,000 CD4 cells per microliter of blood. In a person infected
with HIV, the virus steadily destroys CD4 cells over a period of years,
diminishing the cells' protective ability and weakening the immune system. When
the density of CD4 cells drops to 200 cells per microliter of blood, the
infected person becomes vulnerable to any of about 26 opportunistic infections
and rare cancers, which take advantage of the weakened immune defenses to cause
disease.
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IV
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HOW HIV INFECTION SPREADS
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Scientists have identified three ways that HIV infections spread: sexual
intercourse with an infected person, contact with contaminated blood, and
transmission from an infected mother to her child before or during birth or
through breastfeeding.
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A
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Sex with an Infected Person
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HIV transmission occurs most commonly during intimate sexual contact with
an infected person, including genital, anal, and oral sex. The virus is present
in the infected person's semen or vaginal fluids. During sexual intercourse,
the virus gains access to the bloodstream of the uninfected person by passing
through openings in the mucous membrane-the protective tissue layer that lines
the mouth, vagina, and rectum-and through breaks in the skin of the penis. In
the United States and Canada
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B
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Contact with Infected Blood
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Direct contact with HIV-infected blood occurs when people who use heroin
or other injected drugs share hypodermic needles or syringes contaminated with
infected blood. Sharing of contaminated needles among intravenous drug users is
the primary cause of HIV infection in eastern Europe, particularly in Ukraine , Russia ,
Belarus , and Moldova Georgia , Armenia ,
Azerbaijan , and Kazakhstan in Central Asia .
Less frequently, HIV infection results when health professionals
accidentally stick themselves with needles containing HIV-infected blood or
expose an open cut to contaminated blood. Some cases of HIV transmission from
transfusions of infected blood, blood components, and organ donations were
reported in the 1980s. Since 1985 government regulations in the United States and Canada North America . However, the problem continues to concern
health officials in sub-Saharan Africa . Less
than half of the 46 nations in this region have blood-screening policies. By
some estimates only 25 percent of blood transfusions are screened for the
presence of HIV. WHO hopes to establish blood safety programs in more than 80
percent of sub-Saharan countries by 2003.
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Mother-to-Child Transmission
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HIV can be transmitted from an infected mother to her baby while the baby
is still in the woman's uterus or, more commonly, during childbirth. The virus
can also be transmitted through the mother's breast milk during breastfeeding.
Mother-to-child transmission accounts for 90 percent of all cases of AIDS in
children. Mother-to-child transmission is particularly prevalent in Africa,
where the number of women infected with HIV is ten times the rate found in
other regions. Studies conducted in several cities in southern Africa in 1998 indicate that up to 45 percent of pregnant
women in these cities carry HIV.
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D
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Misperceptions About HIV Transmission
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The routes of HIV transmission are well documented by scientists, but
health officials continually grapple with the public's unfounded fears
concerning the potential for HIV transmission by other means. HIV differs from
other infectious viruses in that it dies quickly if exposed to the environment.
No evidence has linked HIV transmission to casual contact with an infected
person, such as a handshake, hugging, or kissing, or even sharing dishes or
bathroom facilities. Studies have been unable to identify HIV transmission from
modes common to other infectious diseases, such as an insect bite or inhaling
virus-infected droplets from an infected person's sneeze or cough.
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V
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SYMPTOMS
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Without medical intervention, AIDS progresses along a typical course.
Within one to three weeks after infection with HIV, most people experience
flu-like symptoms, such as fever, sore throat, headache, skin rash, tender
lymph nodes, and a vague feeling of discomfort. These symptoms last one to four
weeks. During this phase, known as acute retroviral syndrome, HIV reproduces
rapidly in the blood. The virus circulates in the blood throughout the body,
particularly concentrating in organs of the lymphatic system.
The normal immune defenses against viral infections eventually activate
to battle HIV in the body, reducing but not eliminating HIV in the blood.
Infected individuals typically enter a prolonged asymptomatic phase, a
symptom-free period that can last ten years or more. While persons who have HIV
may remain in good health during this period, HIV continues to replicate,
progressively destroying the immune system. Often an infected person remains
unaware that he or she carries HIV and unknowingly transmits the virus to
others during this phase of the infection.
When HIV infection reduces the number of CD4 cells to around 200 per
microliter of blood, the infected individual enters an early symptomatic phase
that may last a few months to several years. HIV-infected persons in this stage
may experience a variety of symptoms that are not life-threatening but may be
debilitating. These symptoms include extensive weight loss and fatigue (wasting
syndrome), periodic fever, recurring diarrhea, and thrush, a fungal mouth
infection. An early symptom of HIV infection in women is a recurring vaginal
yeast infection. Unlike earlier stages of the disease, in this early
symptomatic phase the symptoms that develop are severe enough to cause people to
seek medical treatment. Many may first learn of their infection in this phase.
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A
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Opportunistic Infections
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If CD4 cell levels drop below 200 cells per microliter of blood, the late
symptomatic phase develops. This phase is characterized by the appearance of
any of 26 opportunistic infections and rare cancers. The onset of these
illnesses, sometimes referred to as AIDS-defining complications, is one sign
that an HIV-infected person has developed full-blown AIDS. Without medical
treatment, this stage may last from several months to years. The cumulative
effects of these illnesses usually cause death.
Often the first opportunistic infection to develop is pneumocystis
pneumonia, a lung infection caused by the fungus Pneumocystis carinii. This fungus infects most people in childhood,
settling harmlessly in the lungs where it is prevented from causing disease by
the immune system. But once the immune system becomes weakened, the fungus can
block the lungs from delivering sufficient oxygen to the blood. The lack of
oxygen leads to severe shortness of breath accompanied by fever and a dry
cough.
In addition to pneumocystis pneumonia, people with AIDS often develop
other fungal infections. Up to 23 percent of people with AIDS become infected
with fungi from the genus Cryptococcus,
which cause meningitis, inflammation of the membranes that surround the brain.
Infection by the fungus Histoplasma
capsulatum affects up to 10 percent of people with AIDS, causing general
weight loss, fever, and respiratory complications.
Tuberculosis, a severe lung infection caused by the bacterium Mycobacterium tuberculosis, typically
becomes more severe in AIDS patients than in those with a healthy immune
system. Between the 1950s and the late 1980s, tuberculosis was practically
eradicated in North America . In the early
1990s, doctors became alarmed when incidence of the disease dramatically
escalated. This resurgence has been attributed to the increased susceptibility
to tuberculosis of people infected with HIV. Infection by the bacterium Mycobacterium avium can cause fever,
anemia, and diarrhea. Other bacterial infections of the gastrointestinal tract
contribute to wasting syndrome.
Opportunistic infections caused by viruses, especially members of the
herpesvirus family, are common in people with AIDS. One of the herpesviruses,
cytomegalovirus (CMV), infects the retina of the eye and can result in
blindness. Another herpesvirus, Epstein-Barr virus (EBV), may cause certain
types of blood cancers. Infections with herpes simplex virus (HSV) types 1 or 2
may result in sores around the mouth, genital area, or anus.
Many people with AIDS develop cancers. The destruction of CD4 cells
impairs the immune functions that halt the development of cancer. Kaposi's
sarcoma is a cancer of blood vessels caused by a herpesvirus. This cancer
produces purple lesions on the skin, which can spread to internal organs and
cause death. B cell lymphoma affects certain cells of the lymphatic system that
fight infection and perform other vital functions. Cervical cancer is more
common in HIV-infected women than in women free from infection.
A variety of neurological disorders are common in the later stage of
AIDS. Collectively called HIV-associated dementia, they develop when HIV or
another microbial organism infects the brain. The infection produces
degeneration of intellectual processes such as memory and, sometimes, problems
with movement and coordination.
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Symptoms in Children
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HIV infection in children progresses more rapidly than in adults, most
likely because the immune systems in children have not yet built up immunity to
many infectious agents. The disease is particularly aggressive in infants-more
than half of infants born with an HIV infection die before age two. Once a
child is infected, the child's undeveloped immune system cannot prevent the
virus from multiplying quickly in the blood. This extensive virus burden speeds
the progression of the disease. In contrast, when adults become infected with
HIV, their immune system generally fights the infection. Therefore, HIV levels
in adults remain lower for an extended period, delaying the progression of the
disease.
Children develop many of the opportunistic infections that befall adults
but also exhibit symptoms not observed in older patients. Among infants and children,
HIV infection produces wasting syndrome and slows growth (generally referred to
as failure to thrive). HIV typically infects a child's brain early in the
course of the disease, impairing intellectual development and coordination
skills. While HIV can infect the brains of adults, it usually does so toward
the later stages of the disease and produces different symptoms.
Children show a susceptibility to more bacterial and viral infections
than adults. More than 20 percent of HIV-infected children develop serious,
recurring bacterial infections, including meningitis and pneumonia. Some
children suffer from repeated bouts of viral infections, such as chicken pox.
Healthy children generally develop immunity to these viral illnesses after an
initial infection.
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VI
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DETECTING AND MONITORING HIV INFECTION
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Since HIV was first identified as the cause of AIDS in 1983, a variety of
tests have been developed that help diagnose HIV infection as well as determine
how far the infection has progressed. Other tests can be used to screen donated
blood, blood products, and body organs for the presence of HIV.
Doctors determine if HIV is present in the body by identifying HIV
antibodies, specialized proteins created by the immune system to destroy HIV.
The presence of the antibodies indicates HIV infection because these antibodies
form in the body only when HIV is present. HIV antibodies form anywhere from
five weeks to three months after HIV infection occurs, depending upon the
individual's immune system. The antibodies are produced continually throughout
the course of the infection.
The standard test to detect HIV antibodies in the blood is the
enzyme-linked immunosorbent assay (ELISA). In this test, a blood sample is
mixed with proteins from HIV. If the blood contains HIV antibodies, they attach
to the HIV proteins, producing a telltale color change in the mixture. This
test is highly reliable when performed two to three months after infection with
HIV. The test is less reliable when used in the very early stage of HIV infection,
before detectable levels of antibodies have had a chance to form. Doctors
routinely confirm a positive result from an ELISA test by using the Western
Blot test, which can detect lower levels of HIV antibodies. In this test a
blood sample is applied to a paper strip containing HIV proteins. If HIV
antibodies are present in the blood, they bind to the HIV proteins, producing a
color change on the paper. The combination of the ELISA and the Western Blot
test is more than 99.9 percent accurate in detecting HIV infection within 12
weeks following exposure.
Once tests confirm an HIV infection, doctors monitor the health of the
infected person's immune system by periodically measuring CD4 cell counts in
the blood. The progressive loss of CD4 cells corresponds to a worsening of the
disease as the immune system becomes increasingly impaired. Doctors also
measure the viral load-the amount of the virus in the blood-using polymerase
chain reaction (PCR) technology. PCR tests measure the level of viral ribonucleic
acid (RNA), a type of nucleic acid, in blood to determine the rate of HIV
growth in an infected person. Knowing the viral load helps doctors estimate an
infected person's survival time. For example, studies show that without
treatment, the average survival time for people with an HIV viral load greater
than 30,000 per microliter of blood is 4.4 years, while those with a viral load
below 10,000 per microliter of blood live for an average of ten years.
A modified ELISA test that detects p24 antigen, a protein produced by
HIV, can determine if specific drug treatments are having a positive effect on
a patient. Blood banks, plasma centers, clinical laboratories, private clinics,
and public health departments also use this p24 antigen test to screen for the
presence of HIV in blood, blood components, and organs before they are used in
medical procedures.
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DIAGNOSING AIDS
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Physicians prefer to differentiate between people who have HIV infection
and those who have AIDS. The Centers for Disease Control and Prevention (CDC),
based in Atlanta , Georgia
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VIII
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TREATMENT
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While no medical treatment cures AIDS, in the relatively short time since
the disease was first recognized, new methods to treat the disease have
developed rapidly. Health-care professionals focus on three areas of therapy
for people living with HIV infection or AIDS: antiretroviral therapy using
drugs that suppress HIV replication; medications and other treatments that
fight the opportunistic infections and cancers that commonly accompany HIV
infection; and support mechanisms that help people deal with the emotional
repercussions as well as the practical considerations of living with a
disabling, potentially fatal disease.
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Antiretroviral Therapies
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Understanding the specific steps in the HIV replication cycle is critical
in order for scientists to develop drugs that attack vulnerable stages within
the cycle. HIV belongs to a unique group of viruses known as retroviruses, so
named because these viruses reverse the usual flow of genetic information
within an infected cell. Most viruses store their genetic material in
deoxyribonucleic acid (DNA), the double-helix structure that makes up genes.
When a virus infects a cell, the viral DNA forms the template for the creation
of messenger RNA, a type of ribonucleic acid. This messenger RNA directs the
formation of specific proteins, and these proteins, in turn, build new virus
particles (see Genetics). In HIV,
however, genetic material is stored in two single-stranded RNA molecules. When
HIV infects a cell, an enzyme called reverse transcriptase copies the genetic
instructions in the virus's RNA and moves it into the DNA. This movement of
genetic information from RNA to DNA is the opposite of that which occurs in
most cells during protein synthesis.
Another HIV enzyme, called integrase, helps the newly formed viral DNA to
become part of the structure of the infected cell's DNA. The viral DNA then
forces the infected cell to manufacture HIV particles. A third HIV enzyme,
called protease, packages these HIV particles into a complete and functional
HIV virus. Over the last decade researchers have created a variety of drugs
that block the action of some of the enzymes used in HIV replication. The three
main classes of drugs used against HIV are nucleoside analogues, non-nucleoside
reverse transcriptase inhibitors, and protease inhibitors.
Nucleoside analogues impede the action of reverse transcriptase, the HIV
enzyme that converts the virus's genetic material into DNA. During this
conversion process, these drugs incorporate themselves into the structure of
the viral DNA, rendering the DNA useless and preventing it from instructing the
infected cell to make additional HIV. The nucleoside analogue known as azidothymidine
(AZT), which became available in 1987, was the first drug approved by the
United States Food and Drug Administration (FDA) to treat AIDS. AZT slows HIV
growth in the body, permitting an increase in the number of CD4 cells, which
boosts the immune system. AZT also prevents transmission of HIV from an
infected mother to her newborn. Since the introduction of AZT, additional
nucleoside analogues have been developed, including didanosine (sold under the
trade name Videx), zalcitabine (HIVID), stavudine (Zerit), lamivudine (Epivir),
and abacavir (Ziagen). These drugs
are not particularly powerful when used alone, and often their benefits last
for only 6 to 12 months. But when nucleoside analogues are used in combination
with each other, they provide longer-lasting and more effective results.
Non-nucleoside reverse transcriptase inhibitors (NNRTIs), introduced in
1996, use a different mechanism to block reverse transcriptase. These drugs
bind directly to reverse transcriptase, preventing the enzyme from converting
RNA to DNA. Three NNRTIs are available: nevirapine (Viramune), delavirdine (Rescriptor),
and efavirenz (Sustiva). NNRTIs work
best when used in combination with nucleoside analogues.
The third group of antiviral drugs, called protease inhibitors, cripples
protease, the enzyme vital to the formation of new HIV. When these drugs block
protease, defective HIV forms that is unable to infect new cells. Protease
inhibitors are more powerful than nucleosides and NNRTIs, producing dramatic
decreases in HIV levels in the blood. This reduced viral load, in turn, enables
CD4 cell levels to skyrocket. The first protease inhibitor, saquinavir (Invirase), was approved in 1995. Since
then other protease inhibitors have been approved, including ritonavir (Norvir), indinavir (Crixivan), nelfinavir (Viracept),
and amprenavir (Agenerase).
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A1
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Drug Resistance
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Clinical studies of treatment with antiretroviral drugs immediately
showed that their benefits are short-lived when a single drug is used alone.
This short-term effectiveness results when HIV mutates, or changes its genetic
structure, becoming resistant to the drug. The genetic material in HIV provides
instructions for the manufacture of critical enzymes needed to replicate the
virus. Scientists design current antiretroviral drugs to impede the activity of
these enzymes. If the virus mutates, the structure of the virus's enzymes
changes. Drugs no longer work against the enzymes, making the drugs ineffective
against viral infection.
Genes mutate during the course of viral replication, so the best way to
prevent mutation is to halt replication. Studies have shown that the most
effective treatment to halt HIV replication employs a combination of three
drugs taken together-for instance, a combination of two nucleoside analogues
with a protease inhibitor. This regimen, called triple therapy, maximizes drug
potency while reducing the chance for drug resistance. The combination of three
drugs is often referred to as an AIDS cocktail. In HIV-infected patients who
have undergone triple therapy, the viral loads reduced significantly, sometimes
to undetectable levels. Their CD4 cell count gradually increased, and they
sustained good health with no complications. With this treatment, some patients
who were near death were able to return to work and normal physical activity.
Triple therapy was introduced in the United States United
States
Despite phenomenal success, triple therapy has some drawbacks. This
multidrug therapy is quite complicated, requiring patients to take anywhere
from 5 to 20 pills a day on a specific schedule. Some drugs must be taken with
food, while others cannot be taken at the same time as certain other pills.
Even the most organized people find it difficult to take pills correctly. Yet,
just one or two lapses in treatment may cause the virus to develop resistance
to the drug regimen.
Many people also find it difficult to deal with the unpleasant side
effects produced by antiretroviral drugs. Common side effects include nausea,
diarrhea, headache, fatigue, abdominal pain, kidney stones, anemia, and
tingling or numbness in the hands and feet. Some patients may develop diabetes
mellitus, while other patients develop collections of fat deposits in the
abdomen or back, causing a noticeable change in body configuration. Some
antiretroviral drugs produce an increase in blood fat levels, placing a patient
at risk for heart attack or stroke. Some patients suffer more misery from the
drug treatment than they do from the illnesses produced by HIV infection.
Perhaps the greatest drawback to triple therapy is its cost, which ranges
from $10,000 to $12,000 a year. This high cost is well beyond the means of
people with low incomes or those with limited health-care insurance. As a
result, the most effective therapies currently available remain beyond the
reach of the majority of HIV-infected people worldwide.
To decrease the toxic effects of drugs and to defer costly therapy, in
2001 United States
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A2
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Postexposure Prevention
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Studies show that under certain circumstances, administering
antiretroviral drugs within 24 hours (preferably within one to two hours) after
exposure to HIV can protect a person from becoming infected with the virus.
Although the effectiveness of postexposure antiretroviral therapy following
sexual exposure to HIV remains uncertain, the CDC recommends that health-care personnel
exposed to HIV infection from a needle stick or other accident take
antiretroviral drugs.
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A3
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Development of New Drugs
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Scientists continue to develop more powerful HIV treatments that have
fewer side effects and fewer resistance problems. Some drugs under
investigation block the HIV enzyme integrase from inserting viral DNA into the
infected cell. Other drugs prevent HIV from binding with a CD4 cell in the
first place, thereby barring HIV entry into cells.
Some scientists focus on ways to fortify the immune system. A biological
molecule called interleukin-2 shows promise in boosting the immune system's
arsenal of infection-fighting cells. Interleukin-2 stimulates the production of
CD4 cells. If enough CD4 cells can be created, they may trigger other immune
cell responses that can overpower HIV infection.
In other research, doctors hope to bolster the immune system with a
vaccine. Most vaccines available today, including those that prevent measles or
poliomyelitis, work by helping the body to create antibodies. Such vaccines
mark specific infectious agents, such as the measles and polio viruses, for
destruction. But many experts believe that an effective HIV vaccine will need
to do more than just stimulate anti-HIV antibodies. Studies are underway to develop
vaccines that also elevate the production of T cells in the immune system.
Scientists hope that this dual approach will prime the immune system to attack
HIV as soon as it appears in the body, perhaps containing the virus before it
spreads through the body in a way that natural immune defenses cannot. The
genetic variability of HIV frustrates efforts to develop a vaccine: A vaccine
effective against one type of HIV may not work on a virus that has undergone
genetic mutation.
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Treatment of Opportunistic Infections
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In addition to antiretroviral therapy to combat HIV infection, effective
drug treatments are available to fight many of the medical complications that
result from HIV infection. Doctors try to prevent infections before they begin
to avoid taxing a patient's weakened immune system unnecessarily. A doctor
instructs an HIV-infected person on ways to avoid exposure to infectious agents
that produce opportunistic infections common in people with a weakened immune
system. Doctors usually prescribe more than one drug to forestall infections.
For example, for those who have a history of pneumocystic pneumonia and a CD4
cell count of less than 200 cells per microliter, doctors may prescribe the
antibiotics sulfamethoxazole and trimethoprim to prevent further bouts of
pneumonia. Patients suffering from recurring thrush may be given the antifungal
drug fluconazole for prolonged periods. For people with CD4 cell counts of less
than 100 cells per microliter, doctors may prescribe clarithromycin or azithromycin
to prevent Mycobacterium avium
infections.
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C
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Support Mechanisms
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A person diagnosed with HIV infection faces many challenges, including
choosing the best course of treatment, paying for health care, and providing
for the needs of children in the family while ill. In addition to these
practical considerations, people with HIV infection must cope with the
emotional toll associated with the diagnosis of a potentially fatal illness.
The social stigma that continues to surround a diagnosis of AIDS because of the
disease's prevalence among gay men or drug users causes many people to avoid
telling family or friends about their illness. People with AIDS often feel
incredibly lonely as they try to cope with a devastating illness on their own.
Loneliness, anxiety, fear, anger, and other emotions often require as much
attention as the medical illnesses common to HIV infection.
Since the AIDS epidemic began in the United States Canada
Counseling centers and churches provide individual or group counseling to
help people with HIV infection or AIDS share their feelings, problems, and
coping mechanisms with others. Family counseling can address the emotions of
other family members who are disturbed by the diagnosis of HIV infection in
another family member. Grief counseling also helps people who have lost friends
or family members to AIDS.
In the United States
and Canada
The United States Congress has passed legislation to help HIV-infected
individuals. In 1990 the Americans with Disabilities Act (ADA) was enacted,
protecting people with disabling diseases, including AIDS, from discrimination
in activities such as applying for jobs or buying a house. The Ryan White
Comprehensive AIDS Resources Emergency Act was established in 1990 and
reauthorized in 1996. This program provides medical and dental care,
counseling, transportation, and home and hospice care for low-income or
uninsured people living with AIDS. The AIDS Drug Assistance Program (ADAP) is
funded in large part by this act and administered by all 50 states. It pays for
costly AIDS medications for people who do not have private insurance and who
are not poor enough to be eligible for Medicaid.
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IX
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PREVENTION
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With a vaccine for AIDS years away and no cure on the horizon, experts
believe that the most effective treatment for AIDS is to prevent the occurrence
of HIV infection. Health officials focus public education programs on altering
risky behaviors linked to HIV transmission, particularly unsafe sexual
practices and needle-sharing by intravenous drug users. Safe-sex campaigns
sponsored by health clinics, social centers, schools, and churches encourage
sexual abstinence or monogamy (sexual relations with only one partner).
Education programs instruct about the proper way to use condoms to provide a
protective barrier against transmission of HIV during sexual intercourse.
Needle-exchange programs, which provide clean needles to drug users, enable
intravenous drug abusers to avoid sharing HIV-contaminated needles.
Needle-exchange programs have been widely criticized because they seem to
condone illicit drug use. However, numerous U.S. United States
and Canada
In the United States ,
the effectiveness of public education programs that target people at risk for
HIV infection was well demonstrated in the gay community of San Francisco , California San Francisco San Francisco
Public education about AIDS has also proven effective in other countries.
Uganda Uganda Uganda
Public health officials have learned that education programs that teach
and reinforce safe behaviors through a series of meetings are more effective
than one-time exposure to public-health information provided in a class
lecture, magazine article, advertisement, or pamphlet. Education programs
tailored to reflect specific ethnic and cultural preferences prove even more
effective. For example, the Canadian Aboriginal AIDS Network creates HIV
education programs that fight the common misperception among the indigenous
peoples of Canada
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HISTORY
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In the short time since the first cases of the AIDS epidemic were
reported in 1981, scientists have identified the viral cause of the illness,
the basic modes of transmission, accurate tests for the presence of infection,
and effective drugs that slow or halt the progression of the disease. During
that same period, governments and grassroots organizations around the world
were spurred into action to meet the growing need for AIDS education,
counseling, patients' rights, and clinical research. Despite these advances,
critics observe that many governments were slow to respond to the crisis. For
example, United States
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A
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Origin of the Virus
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Using computer technology to study the structure of HIV, scientists have
determined that HIV originated around 1930 in rural areas of Central
Africa , where the virus may have been present for many years in
isolated communities. The virus probably did not spread because members of
these rural communities had limited contact with people from other areas. But
in the 1960s and 1970s, political upheaval, wars, drought, and famine forced
many people from these rural areas to migrate to cities to find jobs. During
this time, the incidence of sexually transmitted infections, including HIV
infection, accelerated and quickly spread throughout Africa .
As world travel became more prevalent, HIV infection developed into a worldwide
epidemic. Studies of stored blood from the United States
In 1970, at about the same time that the HIV epidemic was taking hold in Africa , American molecular biologist David Baltimore and
American virologist Howard Temin independently discovered the enzyme reverse
transcriptase, which could be used to identify retroviruses. Over the next ten
years, many retroviruses were identified in animals. But not until 1980,
shortly before the first AIDS cases were recognized in the United States, did
American virologist Robert Gallo identify the first human retroviruses, HTLV-I
and HTLV-II (HTLV stands for human T cell lymphotropic virus).
Other studies demonstrated that these human retroviruses were more
closely related to a retrovirus found in African chimpanzees than to each
other. This discovery suggests that the human retroviruses may have evolved
from retroviruses that originally infected chimpanzees. The chimpanzee
retrovirus likely infected people and underwent mutations to form the human
retrovirus. In 1999 scientists confirmed that HIV spread from chimpanzees to
humans on at least three separate occasions in Central
Africa , probably beginning in the 1940s or 1950s.
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B
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Disease First Identified
|
Beginning in June 1981 the CDC published reports on clusters of gay men
in New York and California
While the disease was making headlines for the speed with which it was
spreading around the world, the cause of AIDS remained unidentified. Fear of
AIDS and ignorance of its causes resulted in some outlandish theories. Some
thought the disease was God's punishment for behaviors that they considered
immoral. These early theories created a social stigma surrounding the disease
that still lingers.
Scientists quickly identified the primary modes of transmission-sexual
contact with an infected person, contact with infected blood products, and
mother-to-child transmission. From these modes of transmission it was clear
that the new illness was spread in a specific manner that matched the profile
of a viral infection. In 1983 French cancer specialist Luc Montagnier and his
colleagues isolated what appeared to be a new human retrovirus from AIDS patients.
They named it lymphadenopathy virus (LAV). Eight months later Gallo and his
colleagues isolated the same virus in AIDS patients, naming the virus HTLV-III.
Eventually, scientists agreed to call the infectious agent human
immunodeficiency virus (HIV). In 1985 a new AIDS-causing virus was discovered
in West Africa . Named HIV-2, the new virus is
closely related to the first HIV, but it appears to be less harmful to cells of
the immune system and reproduces more slowly than HIV-1.
Research leading to the development of the ELISA test was conducted
simultaneously by teams led by Gallo in the United
States and Montagnier in France
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C
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Defining the Illness
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The CDC presented its first definition of AIDS in 1982. The CDC
recommended that physicians diagnose AIDS if a person has an illness known to
be caused by immune deficiency, as long as there is no known cause for this
immune deficiency (people who undergo radiation therapy or who take certain
drugs may impair their immune systems). As more information became known about
the course of HIV infection and the nature of the virus itself, this definition
of AIDS was revised repeatedly to expand the list of illnesses considered
diagnostic indicators of the disease. Early definitions were based on the
opportunistic infections commonly found in HIV-infected men. As a result, many
women who did not have symptoms covered in the official AIDS definition were
denied disability benefits and AIDS-related drug therapies.
The current definition of AIDS was created in 1993 and includes 26
opportunistic infections and cancers, known as diagnostic indicators, that
affect both men and women. The definition also emphasizes the importance of the
level of CD4 cells in the blood. Today doctors make the diagnosis of AIDS in
anyone with a CD4 count below 200 cells per microliter of blood, regardless of
the associated illnesses they may have.
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XI
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SOCIAL PERSPECTIVES
|
Although new and effective AIDS drugs have brought hope to many
HIV-infected persons, a number of social and ethical dilemmas still confront
researchers and public-health officials. The latest combination drug therapies
are far too expensive for infected persons in the developing world-particularly
in sub-Saharan Africa , where the majority of
AIDS deaths have occurred. In these regions, where the incidence of HIV
infection continues to soar, the lack of access to drugs can be catastrophic.
In 1998, responding to an international outcry, several pharmaceutical firms
announced that they would slash the price of AIDS drugs in developing nations
by as much as 75 percent. However, some countries argued that drug firms had
failed to deliver on their promises of less expensive drugs. In South Africa government officials developed
legislation that would enable the country to override the patent rights of drug
firms by importing cheaper generic medicines made in India
and Thailand South
Africa
|
A
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|
Testing AIDS Drugs and Vaccines
|
AIDS research in the developing world has raised ethical questions
pertaining to the clinical testing of new therapies and potential vaccines. For
example, controversy erupted over 1997 clinical trials that tested a shorter
course of AZT therapy in HIV-infected pregnant women in developing countries.
Earlier studies had shown that administering AZT to pregnant women for up to
six months prior to birth could cut mother-to-child transmission of HIV by up
to two-thirds. The treatment's $800 cost, however, made it too expensive for
patients in developing nations.
The controversial 1997 clinical trials, which were conducted in Thailand and other regions in Asia and Africa , tested a shorter course of AZT treatment, costing
only $50. Some pregnant women received AZT, while others received a placebo-a
medically inactive substance often used in drug trials to help scientists
determine the effectiveness of the drug under study. Ultimately the shorter
course of AZT treatment proved to be successful and is now standard practice in
a growing number of developing nations. However, at the time of the trials,
critics charged that using a placebo on HIV-infected pregnant women-when AZT
had already been shown to prevent mother-to-child transmission-was unethical
and needlessly placed babies at fatal risk. Defenders of the studies countered
that a placebo was necessary to accurately gauge the effectiveness of the AZT
short-course treatment. Some critics speculated whether such a trial, while
apparently acceptable in the developing nations of Asia and Africa, would ever
have been viewed as ethical, or even permissible, in a developed nation like
the United States
Similar ethical questions surround the testing of AIDS vaccines in
developing nations. Vaccines typically use weakened or killed HIV to spark
antibody production. In some vaccines, these weakened or killed viruses have
the potential to cause infection and disease. Critics questioned whether it is
ethical to place all the risk on test subjects in developing regions such as
sub-Saharan Africa , where a person infected by
a vaccine would have little or no access to medical care. At the same time,
with AIDS causing up to 5,500 deaths a day in Africa ,
others feel that developing nations must pursue any medical avenue for stemming
the epidemic and protecting people from the virus.
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B
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Economic Burden
|
For the struggling economies of some developing nations, AIDS has brought
yet another burden: AIDS tends to kill young adults in the prime of their
lives-the primary breadwinners and caregivers in families. According to figures
released by the United Nations in 1999, AIDS has shortened the life expectancy
in some African nations by an average of seven years. In Zimbabwe
In Africa , the disease has had a heavy
impact on urban professionals-educated, skilled workers who play a critical
role in the labor force of industries such as agriculture, education,
transportation, and government. The decline in the skilled workforce has
already damaged economic growth in Africa , and
economists warn of disastrous consequences in the future.
|
C
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Social Stigma and Discrimination
|
From the early days of the identification of AIDS, the disease has been
powerfully linked to behaviors that are illegal (such as illicit drug use) or
are considered immoral by many people (such as promiscuity and homosexuality).
Consequently, a diagnosis of AIDS was a mark of disgrace, although medical
research revealed that the disease follows well-defined modes of transmission
that can affect any person. As the extent of the epidemic unfolded,
misinformation about AIDS and how it is transmitted triggered widespread fear
of contracting the disease. Some communities responded with hysteria that
resulted in violence. In the United States
in 1987, a Florida
In addition to social stigma, HIV-infected persons must grapple with more
immediate concerns-a daily struggle for basic medical care and other basic
rights in the face of discrimination and fear because of their HIV status. In China United States Maine United States
Some developing nations, such as Uganda India
In developed nations, some of the stigma attached to a diagnosis of AIDS
has lessened in recent years, in part due to the admissions by public figures
and celebrities, especially in the United States
To some scientists, the AIDS epidemic signals a troubling trend in
humanity's future. Along with other deadly microbial threats of recent
years-most notably Ebola virus, which has caused sporadic epidemics in Africa,
and hantavirus, which broke out in the American Southwest in the early
1990s-AIDS is viewed by some as yet another in a series of emerging diseases
that demonstrate how vulnerable humans are to newly encountered microbes. With
population and land development increasing, humans have encroached farther into
rain forests and other formerly wild areas, unleashing previously unknown
disease agents. Meanwhile, global travel has become faster, more convenient,
and more accessible to many people. Some scientists are worried by these
trends, fearing the potential for an as-yet-unknown pathogen to arise and
spread quickly and lethally around the globe.
The social, ethical, and economic effects of the AIDS epidemic are still
being played out, and no one is entirely certain what the consequences will be.
Despite the many grim facts of the AIDS epidemic, however, humanity is armed
with proven, effective weapons against the disease: knowledge, education,
prevention, and the ever-growing store of information about the virus's
actions.
Contributed By: John G. Bartlett
Microsoft ® Encarta ® Encyclopedia 2004. © 1993-2003 Microsoft Corporation. All rights reserved.
Let us seek from the same encyclopaedia the true
meanings of the words isolate, discover and invent.
ISOLATE:
Basque Language
Basque Language, language spoken by the Basques, the people inhabiting
north central Spain and the
department of Pyrénées-Atlantiques in southwestern France Spain
and Labourdin and Navarrais in France
Linguists have tried for a long time to trace the origin
of the language. Most linguists consider it to be an isolate, or language with
no known relatives; attempts have been made to show an affinity between Basque
and certain other languages such as Iberian (an ancient language of eastern
Spain), Ligurian (an ancient language of northwestern Italy), or the Caucasian
languages of the Caucasus region of Georgia and Russia, but no conclusive proof
exists for these proposals. Basque was almost certainly spoken in ancient
Aquitania, the region of Gascony, France
Although Basque is one of the oldest historically documented languages,
Basque literature is meager. The first Basque book on record was printed in
1545 and is a collection of religious and love poems entitled (in Latin)
Linguae Vasconum Primitivae. The most important Basque work is the translation
of the New Testament that appeared in 1571. Next in importance is a collection
of religious and military chronicles published in the 17th century. Following
the Spanish Civil War (1936-39), the regime of Francisco Franco in Spain
Contributed By:
James F. Shearer
James F. Shearer
Microsoft ® Encarta
® Encyclopedia 2004. © 1993-2003 Microsoft Corporation. All rights reserved.
|
B
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Disease First Identified
|
Beginning in June 1981 the CDC published reports on
clusters of gay men in New York and California
While the disease was making headlines for the speed
with which it was spreading around the world, the cause of AIDS remained unidentified.
Fear of AIDS and ignorance of its causes resulted in some outlandish theories.
Some thought the disease was God's punishment for behaviors that they
considered immoral. These early theories created a social stigma surrounding
the disease that still lingers.
Scientists quickly identified the primary modes of
transmission-sexual contact with an infected person, contact with infected
blood products, and mother-to-child transmission. From these modes of
transmission it was clear that the new illness was spread in a specific manner
that matched the profile of a viral infection. In 1983 French cancer specialist
Luc Montagnier and his colleagues isolated what appeared to be a new human
retrovirus from AIDS patients. They named it lymphadenopathy virus (LAV). Eight
months later Gallo and his colleagues isolated the same virus in AIDS patients,
naming the virus HTLV-III. Eventually, scientists agreed to call the infectious
agent human immunodeficiency virus (HIV). In 1985 a new AIDS-causing virus was
discovered in West Africa . Named HIV-2, the
new virus is closely related to the first HIV, but it appears to be less
harmful to cells of the immune system and reproduces more slowly than HIV-1.
Research leading to the development of the ELISA test
was conducted simultaneously by teams led by Gallo in the United States and Montagnier in France
|
C
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|
Defining the Illness
|
The CDC presented its
first definition of AIDS in 1982. The CDC recommended that physicians diagnose
AIDS if a person has an illness known to be caused by immune deficiency, as
long as there is no known cause for this immune deficiency (people who undergo
radiation therapy or who take certain drugs may impair their immune systems).
As more information became known about the course of HIV infection and the
nature of the virus itself, this definition of AIDS was revised repeatedly to
expand the list of illnesses considered diagnostic indicators of the disease.
Early definitions were based on the opportunistic infections commonly found in
HIV-infected men. As a result, many women who did not have symptoms covered in
the official AIDS definition were denied disability benefits and AIDS-related
drug therapies.
The current definition
of AIDS was created in 1993 and includes 26 opportunistic infections and
cancers, known as diagnostic indicators, that affect both men and women. The
definition also emphasizes the importance of the level of CD4 cells in the
blood. Today doctors make the diagnosis of AIDS in anyone with a CD4 count
below 200 cells per microliter of blood, regardless of the associated illnesses
they may have.
NOW
COMPARE THIS WITH THE EARLIER ENTRY
In the early 1980s deaths by
opportunistic infections, previously observed mainly in organ transplant recipients receiving therapy to
suppress their immune responses, were recognized in otherwise healthy homosexual men. In 1983 French cancer specialist
Luc Montagnier and scientists at the Pasteur Institute in Paris
Infection with HIV does not necessarily
mean that a person has AIDS, although people who are HIV-positive are often
mistakenly said to have AIDS. In fact, a person can remain HIV-positive for
more than ten years without developing any of the clinical illnesses that
define and constitute a diagnosis of AIDS. In 1996 an estimated 22.6 million
people worldwide were living with HIV or AIDS-21.8 million adults and 830,000
children. The World Health
Organization (WHO) estimates that between 1981, when the first
AIDS cases were reported, and the end of 1996, more than 8.4 million adults and
children had developed AIDS. In this same period there were 6.4 million deaths
worldwide from AIDS or HIV. About 360,000 of these deaths occurred in the United States
Clinical Progression of AIDS
The progression from the point of HIV
infection to the clinical diseases that define AIDS may take six to ten years or more. This progression can
be monitored using surrogate markers (laboratory data that correspond to the
various stages of disease progression) or clinical endpoints (illnesses
associated with more advanced disease). Surrogate markers for the various
stages of HIV infection include the declining number of CD4 T-cells, the major
type of white blood cell lost because of HIV infection. In general, the lower
the infected person's CD4 T-cell count, the weaker the person's immune system
and the more advanced the disease state. In 1996 it became evident that the
actual amount of HIV in a person's blood-the so-called viral burden-could be used to predict the progression to
AIDS, regardless of a person's CD4 T-cell count. With advancing technology,
viral burden determinations are quickly becoming a standard means of patient
testing.
An infected person's immune response to
the virus-that is, the person's ability to produce antibodies against HIV-can also be used to
determine the progression of AIDS; however, this surrogate marker is less
precise during more advanced stages of AIDS because of the overall loss of
immune function.
Within one to three weeks after
infection with HIV, most people experience nonspecific flulike symptoms such as
fever, headache, skin rash, tender lymph nodes, and a
vague feeling of discomfort. These symptoms last about one to two weeks. During
this phase, known as the acute retroviral syndrome phase, HIV reproduces to
very high concentrations in the blood, mutates (changes its genetic nature)
frequently, circulates through the blood, and establishes infections throughout
the body, especially in the lymphoid organs. The infected person's CD4 T-cell
count falls briefly but then returns to near normal levels as the person's
immune system responds to the infection. Individuals are thought to be highly
infectious during this phase.
Following the acute retroviral syndrome
phase, infected individuals enter a prolonged asymptomatic phase-a symptom-free
phase that can last ten years or more. Persons with HIV remain in good health
during this period, with levels of CD4 T-cells ranging from low to normal (500
to 750 cells per cubic mm of blood). Nevertheless, HIV continues to replicate
during the asymptomatic phase, causing progressive destruction of the immune
system.
Eventually, the immune system weakens to
the point that the person enters the early symptomatic phase. This phase can
last from a few months to several years and is characterized by rapidly falling
levels of CD4 T-cells (500 to 200 cells per cubic mm of blood) and
opportunistic infections that are not life threatening.
Following the early symptomatic phase,
the infected person experiences the extensive immune destruction and serious
illness that characterize the late symptomatic phase. This phase can also last
from a few months to years, and the affected individual may have CD4 T-cell
levels below 200 per cubic mm of blood along with certain opportunistic
infections that define AIDS. A wasting syndrome of progressive weight loss and
debilitating fatigue occurs in a large proportion of people in this stage. The
immune system is in a state of severe failure. The person eventually enters the
advanced AIDS phase, in which CD4 T-cell numbers are below 50 per cubic mm of
blood. Death due to severe life-threatening opportunistic infections and
cancers usually occurs within one to two years.
This is what I found in the ULTIMATE
edition of
ENCYCLOPAEDIA BRITANNICA (2007) entry on
AIDS
Introduction
AIDS ( is an abbrev.) that translates
into; acquired
immunodeficiency syndrome transmissible disease of the immune
system caused by the human immunodeficiency virus
(HIV). HIV slowly attacks and destroys
the immune system, the body's defence against infection, leaving an individual
vulnerable to a variety of other infections and certain malignancies that
eventually causes death. AIDS is the final stage of HIV infection, during which
time fatal infections and cancers frequently arise.
·
Human
immunodeficiency virus (HIV),
·
colour-enhanced
electron microscope image, 24,000× …
The emergence of AIDS
AIDS was first reported in 1981 by investigators in New
York and California
HIV/AIDS spread to epidemic proportions in the 1980s, particularly in Africa,
where the disease may have originated. Spread was likely facilitated by several
factors, including increasing urbanization and long-distance travel in Africa , international travel, changing sexual mores, and
intravenous drug use. According to the United Nations 2004 report on AIDS, some
38 million people are living with HIV, approximately 5 million people become
infected annually, and about 3 million people die each year from AIDS. Some 20
million people have died of the disease since 1981.
People living in sub-Saharan Africa
account for some 70 percent of all infections, and in some countries of the
region the prevalence of HIV infection of inhabitants exceeded 10 percent of
the population. Rates of infection are lower in other parts of the world, but
the epidemic is spreading rapidly in Eastern Europe ,
India , South and Southeast
Asia, Latin America, and the Caribbean . Rates
of infection are also on the rise in the United
States and Western Europe .
In the United States China , Indonesia , and Vietnam
Transmission
HIV is transmitted by the direct transfer of bodily fluids, such as blood
and blood products, semen
and other genital secretions, or breast milk, from an infected person to an
uninfected person. The primary means of transmission worldwide is heterosexual intercourse
with an infected individual; the virus can enter the body through the lining of
the vagina,
penis,
rectum,
or mouth.
HIV frequently is spread among intravenous drug users who share needles
or syringes. Prior to the development of screening procedures and heat-treating
techniques that destroy HIV in blood products, transmission also occurred
through contaminated blood products; many people with haemophilia
contracted HIV in this way. Today the risk of contracting HIV from a blood
transfusion is extremely small.
In rare cases transmission to health care workers may occur by an
accidental stick with a needle used to obtain blood from an infected person.
The virus also can be transmitted across the placenta
or through the breast milk from mother to infant; administration of
antiretroviral medications to both the mother and infant around the time of
birth reduces the chance that the child will be infected with HIV.
HIV is not spread by coughing, sneezing or casual contact (e.g., shaking
hands). HIV is fragile and cannot survive long outside of the body. Therefore,
direct transfer of bodily fluids is required for transmission. Other sexually
transmitted diseases, such as syphilis,
genital
herpes, gonorrhoea,
and chlamydia,
increase the risk of contracting HIV through
sexual contact, probably through the genital lesions that they cause.
AIDS is a zoonosis,
an infection that is shared by humans and lower vertebrate animals. A virus
that is genetically similar to HIV has been found in chimpanzees
in western equatorial Africa . Interestingly,
this virus, known as simian immunodeficiency virus
(SIV), does not readily cause disease in chimpanzees. The practice of
hunting and butchering chimpanzees for meat may have allowed transmission of
the virus to humans, probably in the first half of the 20th century. A
different form of SIV that infects African green monkeys may have given rise to
the virus called HIV-2. HIV-2 can cause AIDS, but it
does so more slowly than HIV-1. Worldwide, the most common human immunodeficiency virus is
HIV-1 found in Europe and the Americas Western Africa .
Now that we have read the different entries from the same
source, is it any wonder that there is now a concealed politics about the
origins and spread of the virus. One account states unequivocally that it
emanated from homosexuals in america Africa and to complete the falsehood they
now manufacture type 1 & type 2.
See how the cunning British Author rephrased the
origin "HIV/AIDS spread to epidemic proportions in the 1980s,
particularly in Africa, where the disease may have originated. Spread was likely
facilitated by several factors, including increasing urbanization and
long-distance travel in Africa , international
travel, changing sexual mores, and intravenous drug use. …..People living in sub-Saharan Africa account for some 70 percent of all infections, and
in some countries of the region the prevalence of HIV infection of inhabitants
exceeded 10 percent of the population. Rates of infection are lower in other
parts of the world, but the epidemic is spreading rapidly in Eastern
Europe , India ,
South and Southeast Asia, Latin America, and the Caribbean .
WHEN WILL
SCIENTISTS FROM THE WEST BE SINCERE AND REFRAIN FROM DEGRADING THE NEGROID
RACE, PAINTING IT BLACKER THAN IT REALLY IS? CAN'T YOU SEE THERE IS NOW A
POLITICISATION OF HIV-AIDS!
This is merely a
preamble.
I WILL DEBUNK THE
DECEIT LATER.
KEEP YOUR FINGERS
CROSSED FOR NOW.
EBOLA VIRUS WAS AND
STILL IS A POTENTIATION OF ROBERT GALLO'S ORIGINAL TEN-YEAR CREATION OF HIV
VIRUS WHICH HE LATER CONFESSED HE WAS COMMISSIONED TO DELIBERATELY DEPOPULATE
THE WORLD
Monday, 09 November
2015 @ 14:06:33hrs
DR JIDEOFO KENECHUKWU DANMBAEZUE IS STATING IN UNAMBIGUOUS TERMS THAT
BOTH HI-VIRUS AND EBOLA VIRUS WERE MANUFACTURED BY A TEAM OF WHITE SCIENTISTS
LED BY DR ROBERT GALLOOF USA
Can someone explain to me, Dr Jideofo Kenechukwu
Danmbaezue, why the entries in the 1988 version of Microsoft Encarta
encyclopaedia on Acquired Immunodeficiency Syndrome and that of the 2004
version are very different? Why was the detailed history of the development of
the virus absent in the latter version? If there is no ulterior motive for this
discrepancy, then let someone interpret the etymological meanings of the words:
‘isolated', ‘discovered' and ‘invented' in common day usage of the words! What
does each imply, especially the word, ISOLATE ?
THIS IS THE EVIDENCE CLEARLY & UNAMBIGUOUSLY
STATED IN THE FIRST 1988 EDITION OF MICROSOFT ENCARTA ENCYCLOPEDIA
In the early 1980s deaths by
opportunistic infections, previously observed mainly in organ transplant recipients receiving therapy to suppress
their immune responses, were recognized in otherwise healthy homosexual men. In 1983 French cancer specialist
Luc Montagnier and scientists at the Pasteur Institute in Paris
QUOD
ERAT DEMONSTRADUM
Dr Jideofo Kenechukwu Danmbaezue, D.Sc.
[1] "Acquired Immune
Deficiency Syndrome," Microsoft®
Encarta® 98 Encyclopedia. © 1993-1997 Microsoft Corporation. All rights
reserved.
