It was the gefiltefish that did them in, we learn in one of Desowitz' first absorbing tales. Nice Jewish grandmothers in New York City used to buy their fish at local markets supplied with live fish from the midwest by immigrant Scandinavian fishermen--who brought with them a kind of intestinal tapeworm. The grandmothers who cooked by look and taste--not by thermometer--in turn became infested. Other encounters between people and diseases occur further afield: Desowitz, now a professor of tropical medicine at the University of Hawaii and a World Health Organization advisor, is an old tropical hand--revealed, now, as a writer of sparkling prose. He has a two-fold message: ""To ameliorate, if not eradicate, the debilitating diseases of the tropics will require behavioral changes not only on the part of the populations at risk but also on the part of the public-health officials."" The ""but also"" is important. Many of Desowitz's accounts are cautionary tales--of the coming of new diseases with land reform and irrigation, as well as the failure to eliminate endemic diseases because of communications barriers. Well-intentioned lectures on the germ or worm theory of disease are often doomed to fall before local beliefs, social habits, rituals and rites. Thus a noble effort to eliminate malaria in northern Nigeria failed becuase workers told the villagers to take their chloroquine first thing in the morning--two hours before the men would come in from the field for breakfast. A bitter pill on an empty stomach tended to induce nausea and vomiting; the result was noncompliance. On the other hand, the attempt to eliminate filariasis in Samoa succeeded once the aid of the women was sought; these formidable ladies (some of them six-foot, 250 pounders) became convinced and were vigilant in seeing that medication was taken on schedule. Desowitz combines some of the Roueche air of detection and suspense with a wry humor that stands him in good stead when the subject is, for instance, human defecation. A sleeper, then: good style, good content, good sense.