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Did
You Say, AIDS?
By Dr. Vivek Jain
The lady on the phone sounded really
frantic. It was the principal of a well-reputed English medium school.
Ever since a series of articles on AIDS had been run in the local newspapers,
she and the biology teacher of the school had been inundated with questions
from the students. And they found to their horror that most of the facts
about the subject were unclear to them too. Hence the phone call - a request
to deliver a talk on AIDS for the benefit of the teachers and the senior
students of the school. A simple one-hour affair explaining the basics
of the condition so that all confusion was clear, once and for all. She
also wanted a question and answer session following the deliberations.
Well, AIDS being my favourite topic,
I just could not resist the invitation. The talk was fixed for the following
week.
Here’s a summary of the topics discussed
that day [The questions that followed my talk, stretched the session to
almost 2 hours - so much so that a subsequent talk had to be scheduled
just for the questions].
The condition of AIDS could not
have been more aptly named.
Acquired - opposed to congenital,
Immune Deficiency -
ndicating the weakened immune system of the patient,
Syndrome - conglomerate of
numerous signs and symptoms involving a multitude of organ systems.
AIDS is caused by a virus now called
the HIV (Human Immunodeficiency Virus). Three strains have been confirmed,
HIV-I, HIV-II, HIV-III. Viruses basically are extremely small (20 - 300
nanometers) parasites, which multiply inside the cells of human beings
who act as their hosts. Structurally they consist of a nucleic acid core
(which carries the virus genetic information) surrounded by a coat of protein.
[When the virus was discovered way back in 1982 by two independent groups
of researchers, it was known by other names HTLV-III and LAV - terminology
which has now been rejected].
The HIV is made up of two concentric
glycoprotein spheres with a RNA (Ribonucleic Acid) core. The outer surface
of the outer sphere has certain special proteins that help the virus to
attach itself to the body’s immune defence cells - the T4 cells. After
the virus enters the blood stream, it attaches itself to the said defence
cells and its outer surface fuses with that of the cell. The RNA core then
enters the cell and commandeers the reproductive machinery of the cell
to replicate itself many times, These new viruses burst out of the host
cell - killing it in the process - and go on to infect fresh T4 Cells.
All such infected T4 cells are useless for the body and thus the human
defences get crippled, leaving it open to even minor infections.
Though the HIV is present in all
the body fluids, namely - blood, semen, saliva, tears, breast milk, urine
and vaginal secretions, evidence available till now has implicated only
blood, semen and vaginal secretions in transmission. (See Box - I for infectivity
risk). There still is no conclusive proof as regarding breast milk / saliva
transmitting AIDS.
After the virus enters the blood
stream (known as ‘exposure’ in medical parlance), in almost all cases a
fixed sequence of events occurs (see Box-II). A virus coming in contact
/ or deposited on intact skin / mucous membrane - poses no danger. But
even if there is a micro abrasion (often unseen by the naked eye), the
risk increases dramatically.
Unlike many medical conditions where
certain typical features characterise a particular disease, AIDS is completely
different. AIDS by itself doesn’t have any peculiar symptoms - but depending
on the organ system involved it can present itself in numerous garbs. (Hence
the question “ what are the symptoms of AIDS?” is technically a wrong question).
However as a rough guide, one should
keep this disease in mind (even the term AIDS is now no longer in vogue
- more preferred is the term HIV) as one of the probable diagnosis if a
patient presents with any of the following symptoms. Unexplained weight
loss (more than 10 % of body weight), persistent fever (more
than 1 month), diarrhoea (more than 1 month), recurrent apthous (oral)
ulcers, unexplained night sweats and recurrent herpes (A viral infection).
All these just make a loose framework for one to suspect HIV positivity.
You must remember that the presence of these need not always indicate AIDS,
and neither are these symptoms mandatory in confirmed positive HIV patients.
The diagnosis of HIV, just clinically,
both in adults and children is difficult under normal circumstances because
the usual signs and symptoms are non - specific and resemble many common
illnesses.
Apart from the general diseases
that affect any normal individual, HIV patients often are susceptible to
a group of infections called Opportunistic infections.
Organ systems most frequently afflicted
by opportunistic infections include the respiratory, gastrointestinal,
the skin and the nervous system (See Box - III). The reason that such infections
are called opportunistic infections is that, in an HIV positive case, because
of lowered immunity, certain rare and specific organisms get an opportunity
to cause infection not usually available in a healthy person. As a rough
benchmark, if any commonly occurring disease state presents in a widespread,
flared up and rapidly progressive form in addition to it, being resistant
to conventional treatment, one should suspect HIV infection.
Despite universal similarities, there
are certain geographical differences, in which AIDS has been presenting
itself in different parts of the world.
Especially in India, it’s usually
a drug resistant and widespread TB and severe diarrhoea, which have been
most frequently seen, in HIV positive cases. In the US, it is pneumonia
(a rare variety of it), which is the most common clinical presentation.
And finally in Africa severe diarrhoea is the most common symptom, which
is also known as the “Slim disease” because of the acute weight loss it
causes. Though certain findings mentioned earlier can lead one to suspect
HIV infection, some tests are necessary to confirm the diagnosis.
Specific tests like the ELIZA include
the detection of antibodies (or chemical agents with a fixed structure,
which are formed in the body against any foreign agent - in this case the
HIV is called the antigen. The foreign agent can also be a bacteria or
an organ) against the HIV. There are also some other rapid fluorescence
tests, which are routinely done in laboratories. And finally there is the
confirmatory test - the Western blot test. However a HIV test, done with
three different antigens is confirmatory enough. It is extremely important
to remember here, that the tests become positive only 6-12 weeks after
exposure. The latest reports say that this period might be as long as 6
months also. Before that (window period) practically nothing can help us
to diagnose or suspect the condition.
The present status
Of treatment
Specific drugs are now available
for the individual opportunistic infections that occur in HIV positive
patients. For HIV itself only a few drugs have been cleared by the FDA
(Food and Drug Administration - USA) namely AZT (Azidothymidine) and DDI
(didanosine). But there are promising signs from numerous others too. What
is now being promoted is a cocktail - A combination of 2-3 drugs (from
2 different groups) administered simultaneously. Then there are of course
the various vaccines on which hectic research is going on. It is to be
clearly noted that drugs only delay the onset of symptoms, they do not
cure AIDS.
Keeping all this in mind would be
worthwhile especially for AIDS, to heed the aphorism that “ PREVENTION
IS NOT BETTER THAN CURE. IT IS THE ONLY CURE”
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