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- AIDS - What's new ?
- -------------------
-
-
- 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 chromo-
- somes (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, cereb-
- rospinal 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, hemo-
- philiacs 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 wide-
- spread, 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 inter-
- views. 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. Rely-
- ing 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 equip-
- ment 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 pro-
- tection 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 nega-
- tive" 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 them-
- selves 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 trans-
- mitted 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.
-
- Protection the only answer:
- ---------------------------
- The best way to avoid AIDS is to regard it as a highly lethal disease and
- practice commonsense prevention. Avoiding infection is IN ONE'S OWN HANDS.
- People can protect themselves. To halt its spread, people are encouraged to
- obtain and apply accurate AIDS information to their living styles and sexual
- habits in order to reduce the risk of getting or transmitting the virus.
- Sadly, health promoters claim that "reaching the many who don't want to know"
- is no easy task. Health promoters suggest that educators must learn how and
- when to communicate AIDS information - in the right way at "teachable"
- moments. Many Public Health Departments are now taking the lead in
- disseminating education about AIDS with largescale public awareness programs.
-
- What of the future?:
- --------------------
- Many virologists believe that since antibiotics became available in the
- late 1940s we have become too complacent about viral infections, no longer
- take communicable disease seriously, and have modern medical schools which
- devote few teaching hours to anti-infective strategies. In fact, we still
- know little about retroviruses such as HIV. Perhaps special virology research
- centres, like the Virus Research Institute proposed for the University of
- Toronto, will help to halt the tragic toll of AIDS and other as yet unknown
- viruses waiting in the wings.
-
-
- For more information on AIDS or aid for AIDS call: local AIDS committees,
- Public Health Departments, or AIDS Hotlines (in Toronto 392-AIDS.)
-
- =============================================================================
-
- In everyday conversations, AIDS is usually a source for humour. For anybody
- who is suffering from the disease there is very little humour. The best
- prevention is not the thought that "IT COULD NEVER HAPPEN TO ME", if that was
- so all the insurance companies would be out of business.
-
- The most reliable person to be put in-charge of preventing you for getting
- AIDS is YOURSELF!!!!
-
-
- 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 ! !
-
-
- ============================================================================
-
- Thanks to the University of Toronto Faculty of Medicine for the article.
-