Scientists Speculate on HIV’s Ability to Facilitate New Epidemics
Continuing its coverage in observance of the 20th anniversary of the first report of AIDS, Newsday speculates on the progression of HIV and how it may shape future epidemics. Some forecasts estimate that the scope of HIV-positive individuals worldwide could "exceed 200 million," a possibility that "has some biologists worried about the insidious next pathogen that may surface, taking advantage of such an enormous pool of people with compromised immune systems." Dr. Robin Weiss of the Wohl Virion Centre at University College in London elaborated on the scenario, saying, "Where 10% or more of the population is immunocompromised due to HIV infection, just imagine how previously rare opportunistic infections could rapidly evolve to become novel human-to-human pathogens." Weiss also wrote in a recent article in the British journal Nature, "Microbes that are poorly adapted for human infection could become well adjusted," first striking immunocompromised AIDS patients and then moving to healthy humans, "provided they learn the tricks of human-to-human transmission." Newsday notes that this phenomenon already has occurred amidst the AIDS epidemic. "Unusual ailments" have struck some HIV-positive populations and spread to the communities around them, including cryptosporidiosis, an intestinal disease transmitted through contaminated water; multi-drug resistant tuberculosis; Herpes simplex virus; and Mycobacterium avium, a "bird form" of tuberculosis. Dr. David Ho, director of the Aaron Diamond AIDS Research Center, expressed particular concern for the relationship between AIDS and TB, saying, "When I went to rural areas in China, you could just go and track the HIV epidemic by TB. And that could really take off in Asia as the [AIDS] epidemic blossoms."
HIV Mutates Faster than Previously Thought
Other scientists have expressed concern over the virus' ability to rapidly mutate and its potential to resurrect "ancient" retroviruses that have become part of normal human DNA and account for about 8% of the human genome. At Cold Spring Harbor Laboratory's annual retrovirus meeting last week, Carrie Dykes and colleagues from the Rochester University Medical Center reported on findings that HIV mutates more rapidly than previously thought, "both through mutations and by combining bits of one HIV strain with bits from another." In response to this finding, Weiss said, "[O]ne nightmare scenario ... would be if HIV were to change its mode of transmission ... If Yersinia pestis can switch from flea-borne bubonic plague to the airborne pulmonary form of the disease, could HIV also sample new transmission dynamics -- adding saliva, aerosol or (insect) vectors to the sex and blood it already enjoys?" (Garrett, Newsday, 5/31).