Calculating The Odds

AIDS is not easy to catch, even from an infected sex partner. But researchers at last week's 27th Interscience Conference on Antimicrobial Agents and Chemotherapy, in Manhattan, presented further evidence that the odds are not equal for all players in today's sexual roulette. Drawing on a study of 357 men at a venereal-disease clinic in Nairobi, Microbiologist William Cameron reported that uncircumcised men are 9 1/2 times as likely as circumcised males to become infected after exposure. According to Cameron, "The mucosal membrane underneath the foreskin may trap the virus, making it more likely to enter the bloodstream."

Cameron and others at the conference also reported that men with genital ulcers -- caused by such infections as herpes simplex 2, syphilis or chancroid -- were three times as vulnerable to the AIDS virus as those who were lesion free. "An ulcer breaks the integrity of the skin and allows infected blood to come into contact with a sexual partner," says Cameron. Thus, he adds, controlling treatable diseases like herpes and educating uncircumcised men about their risk could make a slight dent in the so far incurable scourge.