EFFECTS OF REPEATED EXPOSURES OF HYPERSENSITIVE HUMANS AND LABORATORY RABBITS TO MOSQUITO ANTIGENS

Two methods of altering reactivity to mosquito bites were studied, viz., repeated exposures of hypersensitive human volunteers to mosquito bites, and injections of bite-sensitive rabbits with mosquito extracts.In one of the seven participating human volunteers, the delayed reaction was eliminated entirely while in three others certain aspects of this reaction were altered. Although pruritus was reduced in all subjects, no other feature of the immediate reaction became altered.The level of hypersensitivity in rabbits remained unchanged following use of graded doses of mosquito extract as a desensitization procedure. However, a single intravenous injection completely desensitized rabbits temporarily. Extracts of Aedes atropalpus, A. pionips, and Culex pipiens were as effective in this procedure as was A. aegypti extract in desensitizing aegypti-sensitive animals.