Human Immunodefiency Virus
Before descending into a welter of detail, let it be said from the start that prevention is still the only reliable way to fight the HIV monster.
AIDS, acquired immunodificiency syndrome ("syndrome" means the occurrence together of a characteristics group or pattern of symptons), has been widely called a modern Black Death. Would that this were so, because then the cure would be easy. The comparison is valid, however, when one considers the state of fear and helplessness that AIDS has engendered since it was recognized in the early 1980s. The tenth International Conference on AIDS in 1994 was notable for neither optimism nor pessimism, but lost of realism. AIDS is simply going to be around for a long, long, time. Scientists are now reemphasizing basic research over clinical advances--not exactly going back to square one, but close. After a decade of frenetic investigation at the forefront of virology, it is apparent that HIV and its effects on the immune system are not yet understood deeply enough to lead to dependable treatments.
A disease as catastrophic as AIDS takes on myriad brands of sociopolitical baggage, clouding realities that are horrid enough on their own. Thw World Health Organization estimates that 17 million people are infected with HIV and 4million have AIDS. MOre than 90 ercent of AIDS cases occur in Thirld-World countries. The largest number of cases, estimated at more than 2.5 million, is in sub-Saharan Africa, where there are more than 10 million HiV-infected adults. In the United States, AIDS is still overwhelmingly an affliction of homosexual and bisexul men(47 percent of reported cases in 1993) and injecting drug users (28 percent of reported cases in 1993). Among racial and ethnic groups, African-Americans ans Hispanics account for both the majority of reported cases (54 percent in 1993) and the greatest annual increases. Heterosexual transmission, 42 percent of which was related to contact with an injecting drug user, occurred predominantly in these groups (78 percent of men and 74 percent of women in 1993). Factoring in age reveals an even grimmer picture: in 1993 minorities account for 51 pervent of reported cases among adult and adolescent males and 75 percent of cases among such females. Among children (younger than thirteen years old), 84 percent of AIDS cases were minorities. The AIDS rate for black women was about 15 times greater than for white women and almost five times greater for black men than for white men. In 1991, AIDS was the leading cause of death among black and Hispanic males aged 25 to 44 and the third leading cause for women in the same age group (in overall American population, the ten leading causes of death, in decreasing order, are heart disease, cancer, stroke, lung disease, accidents, pneumonia, and influenza, diabetes, AIDS, suicide, and homicide).
These numbers are chronic dynamite because communal responses to epidemics are always easier to organize and sustain when the disease is perceived as being universal rather than marginal. Throughout history, diseases that disproportionately strike poor people (or people practicing what the larger society defines as vice) have been stigmatized to an extent that ultimately proves more damaging to society than the maladies themselves. Top federal officials in the United States originally opposed efforts to confront AIDS, apparently because of bigotry toward gay men and drug addicts. Former Surgeon General C. Everett Koop's comments in 1991, reported in Lederberg et al., Emerging Infections, are often cited as testimony to this scandal:"Even though the Canters for Disease Control Commissioned the first AIDS task force as early as June 1981, I, as Surgeon Reagan was not allowed . Whenever I spoke on a health issue a a press conference of a network morning TV show, the governmant public affairs people told the media in advance that i would not answer questions on AIDS, and i was not to be asked any questions on the subject. I have never understood why these peculiar restrians were placed on me. And althouh I have sought the explanation, I still don't know the answer." Despite the fact that AIDS research is now well institutionalized in the medical establishment, continued opposition to sex education , condom distribution in public schools, and cleanneedle programs shows the reach of such "peculiar restraints," which can amount to a de facto death sentence.
Unlike the Black Death, which tended to come and go, AIDS may belong in the same realm as cancer or heart disese. That is, for some but not all populations it is an endemic killer. Or it may be similar to tuberculosis in the last century. It differs from all three points of comparison because it is totally preventable, communicable but not contagious. Of course, as a disease that is largely venereal, like syphilis, AIDS is subject to the debased mentality of divine retribution.
The literature on AIDS is already vast and perhaps the fastest growing body of medical research. Interested lay readers cab stay abreast with the journals Science and Nature. Briefly, HIV(human immnuodeficiency virus) is the third of five human retroviruses that have been discovered since 1980 (there are undoubtedly more). Aretrovirus is one containing an enzyme, reverse transcriptase, that converts viral RNA into a DNA copy that becomes part of the host cell's DNA. Before that, this class of pathogens had been connected only with various diseases in animals. HIV which actually erfers to two closely related viruses that cause AIDS in separate geographical regions, is part of a class of retroviruses known as lentiviruses traditionally associated with chronic arthritis and anemia. (Lentiviruses are retroviruses that cause slowly progressive, often fatal diseases.) HIV's unprecedented, tragic specialty is that it likes to attach itself to the very cells that turn on and amplify our immune system--the socalled T lymphocytes, specifically those with a protein called CD4 on their surface, which is the actual hookup point for HIV. Other lentiviruses do the same thing in cows and cats.
The immune system fights a long, ferocious, but ultimately losing battle against the AIDS virus. In late stages of the infection, victims lose and replace about 2 billion CD4 lymphocyte cells a day, while new virus lose and replace about 2 billion CD4 lymphocyte cells a dat, while new virus particles appear at a rate between 100 million and 680 million a day. Other viral diseases, such as the flu or hepatitis, may also trigger warfare of such scope, but for a relatively brief time.
This is what makes the development of a single "magic bullet" vaccine so unlikey . No one knows if a vaccine made from a strain will protect against others. THirteen experimental AIDS vaccines have been given to more than 1,500 volunteers in the United States since 1988, but federal health officials have so far rejected large-scale trials due to lack of confidence in the potency. The World Health Organization nonetheless plans to test two such vaccines , probably in Thailand and Brazil, in a desperate attempt to find one that provides even a low degree of protection. If the gods had wanted to deign a perfect time bomb, it would look like HIV, which perhaps helps to explain why some people hang on to the myth that virus was created by biological warfare experts.
Where did it come from? THe short answer is that no one knows. The fact that there are similar lentiviruses in animals suggest a plausible source, but how HIV hopped into humans is unclear; monkey bite is as good a guess as any. (The earlist documented case of HIV infection was found in a 1959-vintage blood sample from a central Africa.) Epidemiological evidence suggests that it traveled along the Mombasa-Kinshasa highway in Africa and hence to the United States during the mid 1970s, where it was first transmitted via intercourse among highly promiscuos (that is, hundreds of different partners a year) gay men in San Francisco and New York. By mid-1981 the Centers for Disease Control began to notice in young gay men rare diseases--pneumocystis carinii pnuemonia and Kaposi's sercoma--that had previously occured only in people with damaged immune systems. To other industralized nations AIDS than became "the American disease." Because the virus passes easily in blood, intravenous-drug users were the next vulnerable pool, along with the much smaller number of hemophiliacs and others who received contaminated transfusions. Since the virus can also go from person to person through vaginal intercourse(the primary route in Afirica), the coterie of sexual partners of these victims was sonn infected, too.
And so on and so on. In the viscous AIDS circle, you essentially experience all of your lover;s old flames. Pathogens adapted for this kind of infection tend to become permanent parts of the human condition, regardless of whether cures exist. Thw World Health Organization has estimated that worldwide, forty million people could be infected by the year 2000. Still, the authors of the most comprehensive survey ever of Americans sexual habits, released in 1994 under the auspices of the University of Chicago, concluded that HIV infection and AIDS are unlikely to become epidemic in the general U.S. population because Americans tend to have sex with partners from similar social milieus. With few "bridges" between the marginal and the mainstream , the disease will not spread easily from those groups already hardest hit. Besides, more than 80 percent of American adults have only one sexual partner, or none at all, in a year's time, the survey found.
The risk of getting AIDS from casual, household, or workplace contact is still put at near zero, even from personal items such as toothbrushes, razors, clippers, and towels. Ditto fro blood-carrying insects like ticks or mosquitoes. In addition to blood, the virus can be found in semen, breast milk, vaginal secretions, and saliva, though there is no evidence that AIDS can be caught from an infected persons's spit , as in coughing or sneezing. Outside the body, HIV is easily killed by common disinfectants like alcohol or peroxide.
Could the extreme mutability of HIV someday result in a contagious virus, like, say polio or measles?While theoretically possible, the natural drift of evolution is toward an organism's lower virulence in a given population, not higher
So, lets end on that tiny note of optism.