Essay About White Blood Cells And Chicken Pox

Aids – Whats New?
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AIDS – Whats new ?
Is the message getting through? We already know enough about AIDS
toprevent its spread, but ignorance, complacency, fear and bigotry
continue to stop many from taking adequate precautions to stop the
risk of getting the aids virus.
We know enough about how the infection is transmitted to protect
ourselves from it without resorting to such extremes as mandatory
testing, enforced quarantine or total celibacy. But too few people
are getting the AIDS message they just can
get the message
thought their minds. Perhaps many simply don
like or want to
believe what they hear,preferring to think that AIDS “can
happen
to them.” Experts repeatedly remind us that infective agents do not
discriminate, but can infect any and everyone. Like other communicable
diseases, AIDS can strike anyone. It is not necessarily confined to
a few high-risk groups. We must all protect ourselves from this
infection and teach our children about it in time to take effective
precautions. Given the right measures, no one need get AIDS.
The pandemic continues:
Many of us have forgotten about the virulence of widespread epidemics,
such as the 1917/18 influenza pandemic which killed over 21 million people,
including 50,000 Canadians. Having been lulled into false security by modern
antibiotics and vaccines about our ability to conquer infections, the Western
world was ill prepared to cope with the advent of AIDS in 1981. (Retro-
spective studies now put the first reported U.S. case of AIDS as far back as
1968.) The arrival of a new and lethal virus caught us off guard. Research
suggests that the agents that are responsible for AIDS probably dates from
the 1950s,with a chance infection of humans by a modified Simian virus found
in African green monkeys. Whatever its origins, scientists surmise that the
disease spread from Africa to the Caribbean and Europe, then to the U.S.
Current estimates are that 1.5 to 2 million Americans are now probably HIV
carriers,with higher numbers in Central Africa and parts of the Caribbean.
Recapping AIDS – the facts:
AIDS is an insidious, often fatal but less contagious disease than measles,
chicken pox or hepatitis B. AIDS is thought to be caused primarily by a virus
that invades white blood cells (lymphocytes) – especially T4-lymphocytes or
T-helper cells – and certain other body cells, including the brain. In 1983
and 1984, French and U.S. researchers independently identified the virus
believed to cause AIDS as an unusual type of slow-acting retrovirus now
called “human immunodeficiency virus” or HIV. Like other viruses, HIV is
basically a tiny package of genes that imfect the blood cells. But being a
retrovirus, it has the rarecapacity to copy and insert its genes right into
a human cells own chromosomes (DNA). Once inside a human host cell the
retrovirus uses its own enzyme, reverse transcriptase, to copy its genetic
code into a DNA molecule which is then incorporated into the hosts DNA.
The virus becomes an integral part of the persons body, and is subject
to control mechanisms by which it can be switched “on” or “off”. But the
viral DNA may sit hidden and inactive within human cells for years, until
some trigger stimulates it to replicate. There for the HIV virus may
not produce illness until its genes are “turned on” five, ten,
fifteen or perhaps more years after the initial infection.
During the latent period, HIV carriers who harbour the virus without any
sign of illness can unknowingly infect others. On average, the dormant virus
seems to be triggered into action three to six years after first invading
human cells. When switched on, viral replication may speed along, producing
new viruses that destroy fresh lymphocytes. As viral replication spreads, the
lymphocyte destruction virtually sabotages the entire immune system. In
essence, HIV viruses do not kill people, they merely render the immune system
defenceless against other “opportunistic: infections, e.g. yeast invasions,
toxoplasmosis, cytomegalovirus and Epstein Barr infections, massive herpes
infections, special forms of pneumonia (Pneumocystis carinii – the killer in
half of all AIDS patients), and otherwise rare malignant tumours (such as
Kaposis sarcoma.)
Cofactors