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Expository Essay on AIDS

 

  Is the message getting through? We already know enough about AIDS to

prevent its spread, but ignorance, complacency, fear and bigotry continue

to stop many from taking adequate precautions.

 

  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 heeding the

AIDS message. Perhaps many simply don't like or want to believe what they

hear, preferring to think that AIDS "can't 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 agent 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. But

being a retrovirus, it has the rare capacity to copy and insert its genes

right into a human cell's 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

host's DNA. The virus becomes an integral part of the person's 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. Thus HIV 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 Kaposi's sarcoma.)

 

Cofactors may play a crucial contributory role: --------------------------

---------------------

 

  What prompts the dormant viral genes suddenly to burst into action and

start destroying the immune system is one os the central unsolved

challenges about AIDS. Some scientists speculate that HIV replication may

be set off by cofactors or transactivators that stimulate or disturb the

immune system. Such triggers may be genetically determined proteins in

someone's system, or foreign substances from other infecting organisms -

such as syphilis, chlamydia, gonorrhea, HTLV-1 (leukemia), herpes, or CMV

(cytomegalovirus) - which somehow awaken the HIV virus. The assumption is

that once HIV replication gets going, the lymphocyte destruction cripples

the entire immune system. Recent British research suggest that some people

may have a serum protein that helps them resist HIV while others may have

one that makes them genetically more prone to it by facilitating viral

penetration of T-helper cells. Perhaps, says one expert, everybody exposed

to HIV can become infected, but whether or not the infection progresses to

illness depends on multiple immunogenic factors. Some may be lucky enough

to have genes that protect them form AIDS!

 

Variable period until those infected develop antibodies: -----------------

---------------------------------------

 

  While HIV hides within human cells, the body may produce antibodies, but,

for reasons not fully understood, they don't neutralise all the viruses.

The presence of HIV antibodies thus does not confer immunity to AIDS, nor

prevent HIV transmission. Carriers may be able to infect others. The usual

time taken to test positive for HIV antibodies after exposure averages

from four to six weeks but can take over a year. Most experts agree that

within six months all but 10 per cent of HIV-infected people "seroconvert"

and have detectable antibodies.

 

  While HIV antibody tests can indicate infection, they are not foolproof.

The ELISA is a good screening test that gives a few "false positives" and

more "false negatives" indicating that someone who is infected has not yet

developed identifiable antibodies.) The more specific Western Blot test,

done to confirm a positive ELISA, is very accurate. However, absence of

antibodies doesn't guarantee freedom form HIV, as someone may be in the

"window period" when, although already infected, they do not yet have

measurable levels of HIV antibodies. A seropositive result does not mean

someone has AIDS; it means (s)he is carrying antibodies, may be infectious

and may develop AIDS at some future time. As to how long seropositive

persons remain infectious, the June 1987 Third International Conference on

AIDS was told to assume "FOR LIFE".

 

What awaits HIV-carriers who test positive?: -----------------------------

---------------

 

  On this issue of when those who test HIV positive will get AIDS, experts

think that the fast track to AIDS is about two years after HIV infection;

the slow route may be 10, 15, or more years until symptoms appear. Most

specialists agree that it takes at least two years to show AIDS symptoms

after HIV infection, and that within ten years as many as 75 per cent of

those infected may develop AIDS. A report from Atlanta's CDC based on an

analysis of blood collected in San Francisco from 1978 to 1986, showed a

steady increase with time in the rate of AIDS development among HIV-

infected persons - 4 percent within three years; 14 percent after five

years; 36 percent after seven years. The realistic, albeit doomsday view

is that 100 percent of those who test HIV-positive may eventually develop

AIDS.

 

Still spread primarily by sexual contact: --------------------------------

---------

 

  AIDS is still predominantly a sexually transmitted disease: The other

main route of HIV infection is via contaminated blood and shared IV

needles. Since the concentration of virus is highest in semen and blood,

the most common transmission route is from man to man via anal intercourse,

or man to woman via vaginal intercourse. Female HIV carriers can infect

male sex partners. Small amounts of HIV have been isolated from urine,

tears, saliva, cerebrospinal and amniotic fluid and (some claim) breast

milk. But current evidence implicates only semen, blood, vaginal

secretions and possibly breast milk in transmission. Pregnant mothers can

pass the infection to their babies. While breastfeeding is a rare and

unproven transmission route, health officials suggest that seropositive

mothers bottle feed their offspring.

 

  AIDS is not confined to male homosexuals and the high risk groups: There

are now reports of heterosexual transmission - form IV drug users,

hemophiliacs or those infected by blood transfusion to sexual partners.

There are a few reported cases of AIDS heterosexually acquired from a

single sexual encounter with a new, unknown mate. And there are three

recent reports of female-to-female (lesbian) transmissions.

 

Spread of AIDS among drug users alarming: --------------------------------

---------

 

  In many cities, e.g. New York and Edinburgh, where IV drug use is

widespread, IV drug users often share blood-contaminated needles. In New

York, more than 53 percent of drug users are HIV-infected and may transmit

the infection to the heterosexual population by sexual contact and

transmission from mother to child. Studies in Edinburgh, where 51 percent

of drug users are HIV-infected, show that providing clean needles isn't

enough to stem infection. Even given free disposable needles, many drug

abusers preferred the camaraderie of shared equipment. Only with added

teaching programs and free condom offers, are educational efforts likely

to pay off. In New Jersey, offering free treatment coupons plus AIDS

education brought 86 percent of local drug users to classes. A San

Francisco program issued pocket-size containers of chlorine bleach to

IVDAs with instructions on how to kill HIV viruses. The Toronto Addiction

Research Foundation notes a similar demand for AIDS information.

 

Risk of infection via blood transfusion very slight: ---------------------

-------------------------------

 

  Infection by blood transfusion is very rare in Canada today. As of

November 1985, the Red Cross, which supplies all blood and blood products

to Canadian hospitals, had routinely tested all blood donations for the

HIV antibody. In 1986, when we last discussed AIDS, the Red Cross reported

the incidence of HIV-positive blood samples as 25 in 100,000. Now, at the

start of 1988, only 10 per 100,000 blood samples are found to be infected

which, of course, are discarded. Only a tiny fraction of HIV positive

blood (from HIV-infected people who haven't yet developed detectable

antibodies) can now slip through the Red Cross screening procedure. The

minimal risk is further decreased by screening methods, medical history-

taking, questionnaires and donor interviews. Very few people at risk of

AIDS now come to give blood. The "self-elimination form", filled out in a

private booth, allows any who feel compelled by peer pressure to donate

blood, total privacy to check the box that says "Do not use my blood for

transfusion."

 

  As to banking one's own blood, or autologous donations, the Red Cross

permits a few "medically suitable" people, referred by their physician, to

store their blood if they are likely to need blood transfusion in upcoming

elective surgery. They can bank up to four units of blood, taken in the

five weeks before surgery.

 

  Finally - it can be categorically stated - IT IS ABSOLUTELY IMPOSSIBLE

TO GET AIDS BY GIVING BLOOD!!!

 

Minimal risk to health care workers: ------------------------------------

 

  While health care personnel face a slight risk of HIV infection, all

cases reported to date have been due to potentially avoidable mishaps or

failure to follow recommended precautions. Of thousands caring for AIDS

patients worldwide, only a tiny percentage has become infected, and so far

no Canadian health personnel have become HIV-infected. A survey done by

the Federal Centre for AIDS (FCA) of 50 workers occupationally exposed to

AIDS showed that none became infected. A british hospital study on staff

looking after 400 AIDS patients over several years found none who became

HIV-positive. In one U.S. survey, 7 out of 2,500 health care workers

seroconverted and developed HIV antibodies all by potentially avoidable

accidents such as needle pricks, exposure to large amounts of blood, body

fluids spattered into unprotected mouth, eyes or open sores. The reported

mishaps underscore the need for rigorous, vigilant compliance with

preventive guidelines.

 

Universal body substance precautions (BSP) urged: ------------------------

-------------------------

 

  The newest guidelines suggest that every health care worker, including

dentists, should handle all blood and body fluids as if infectious.

Testing all patients for HIV is not practical and does not confer

protection. Relying on tests that are not 100 per cent accurate would only

induce a false sense of security. Rather than trying to identify infected

persons, the CDC and Ottawa's FCA now promote a philosophy that regards

all patients as potentially infected. (At Johns Hopkins in Baltimore,

about six percent of admissions to the Traumatic Emergency Unit recently

tested HIV-positive.) Hospital and health care workers (including those

caring for patients at home) are encouraged to "think AIDS" and protect

themselves. All patients should be handled in a way that minimizes

exposure to blood and body fluids, e.g. by always wearing gloves when

touching open sores, mucous membranes, taking blood, attending emergencies,

putting in IV needles, touching blood-soiled items, with scrupulous hand-

washing between patients (and whenever gloves are removed), wearing masks,

eye protection, plastic aprons and gowns when appropriate. Taking such

precautions will not only protect against AIDS but also against more

infectious agents such as hepatitis B and some hospital acquired

infections. We are all being forced to remember stringent anti-infection

rules!

 

Absolutely no evidence of spread by casual contact: ----------------------

-----------------------------

 

  All the research to date points to the fact that AIDS is not very easy

to catch. One University of Toronto microbiologist speculates that those

with high antibody counts are probably not very infectious. The most

infectious appear to be seemingly healthy persons carrying HIV without any

sign of disease as yet.

 

  AIDS CANNOT BE PICKED UP CASUALLY via doorknobs, public washrooms,

shared school books, communion coups, cutlery or even by food handlers

with open cuts. A relatively weak virus, HIV is easily killed by a dilute

1 in 10 solution of Javex/bleach, rubbing alcohol and other disinfectants.

Even where parents or caregivers have cleaned up HIV-infected blood, vomit

or feces, HIV has not been transmitted. It is perfectly safe to share a

kitchen, bathroom, schoolroom or workbench with HIV-infected individuals.

But it is inadvisable to share toothbrushes, razors, acupuncture needles,

enema equipment or sharp gadgets, which could carry infected blood through

the skin.

 

  ORDINARY, NONSEXUAL WORKPLACE AND CHILDHOOD ACTIVITIES DON'T TRANSMIT

AIDS. The rare exception might be direct blood-to-blood contact via cuts

or wounds if infected blood (in considerable amounts) spills onto an open

sore. Even in such cases a swab with dilute bleach can kill HIV viruses.

 

Not spread by mosquitoes and other insects: ------------------------------

-------------

 

  There's no evidence of HIV transmission by insects. Researchers report

that the AIDS virus cannot multiply or survive inside a mosquito. The

infection pattern in Africa - where children who are not sexually active

might be expected to have AIDS if mosquito bites were a real threat -

shows no sign of insect transmission.

 

Vaccines still a way off: -------------------------

 

  Scientists caution that a safe, effective vaccine against HIV may be at

least a decade away, mainly because, like the influenza virus, HIV mutates

(changes structure) quickly, producing different strains. (Several

different HIV strains have already been isolated.) An ideal vaccine must

be able to stimulate neutralization of both "free" viruses and those

hidden within lymphocytes, such as T-helper cells. Researchers in various

countries have developed and are testing a few preliminary vaccines. One

sub-unit vaccine, made from virus coat material (a glycoprotein)

genetically cloned in an insect virus (the baculovirus, which attacks

moths and butterflies but no humans) has been shown to stimulate an immune

response in experimental animals. Another preliminary vaccine, produced by

cloning modified Vaccinia viruses, containing a portion of HIV envelope,

is about to enter clinical trials in New York. (It would be applies, like

the old smallpox vaccine, into a small scratch.) But to date no vaccine

tried in animals or humans has been shown to prevent AIDS.

 

Testing no solution: --------------------

 

  Large scale, screening of the public for HIV antibodies offers little

protection because today's apparent negatives can become infected tomorrow

or test seropositive when antibodies develop in those already harboring

HIV.  Reliance on tests could lull people into false complacency. A "false

negative" result may fool someone into risky sexual behaviour. Curiously,

despite a widespread demand for tests, especially among high-risk groups,

a study in Pittsburgh showed that 46 percent of a group of

homosexual/bisexual men tested did not return for or want their antibody

test results. Many health experts therefore believe that mandatory testing

would be useless as HIV antibody tests only indicate exposure, not

necessarily infectivity. As one University of Toronto virologist puts it:

"Widescale compulsory screening for HIV antibodies is not necessarily

useful and will do nothing to promote prevention or cure. What's needed

perhaps is more accurate knowledge about the disease and more responsible

behaviour rather than testing."

 

  Those who should consider testing might include people known to be at

high risk and any who think they may have been HIV-infected or who wish to

be tested and have discussed it with their physician. What's needed, as

with any infectious disease, is not more testing buy more precautions

against infection.

 

Message clear but still largely unheeded: --------------------------------

---------

 

  Despite a veritable blitz of AIDS information, experts claim that too

few people are changing their lifestyles or behaviour sufficiently to

protect themselves from AIDS. A recent Canadian poll revealed widespread

ignorance of the fact that AIDS is primarily a sexually acquired infection,

not caught by casual touch. The survey showed that although sexual

intercourse among adolescents has risen steeply in the past 10 years, less

than 25 percent of those aged 18 to 34 have altered their sexual

behaviour to protect themselves against AIDS, i.e. by consistent use of

condoms and spermicide.

 

  THE CENTRAL MESSAGE IS CLEAR: UNLESS ABSOLUTELY SURE (and monogamy is no

guarantee) THAT YOUR SEX PARTNER IS HIV-FREE, USE A CONDOM (latex, not

made of animal material) plus a reliable spermicide (e.g. one containing

nonoxyl-9). Studies with infected haemophiliacs show that condom use by a

regular sex partner reduces infection risks, compared to unprotected sex.

And regular condom use may bring the added reward of preventing other

sexually transmitted diseases such as gonorrhea and chlamydia or unwanted

pregnancy.

 

  Many educators say that, by whatever means, AIDS information must get

out to young people at an early enough age for them to absorb it before

becoming sexually active. Only by acting upon accurate AIDS information

can people protect themselves, their sex partners, families and ultimately

society from this disease.

 

     T A K E   P R E V E N T I V E   P R E C A U T I O N S !

 

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