THE LOGIC OF VISCERAL LEISHMANIASIS CONTROL

Mathematical models are used to compare the effectiveness of various u ntested, unused, and undeveloped methods for controlling canine and hu man zoonotic visceral leishmaniasis (ZVL), including insecticides, vac cines, killing serologically positive and sick dogs, and drugs. For gi ven percentage changes in control parameters, insecticides are the mos t effective control method. Where transmission occurs peridomestically and vectors are accessible to treatment, as in parts of tropical Amer ica, insecticides are expected to reduce the incidence of human ZVL ev en more effectively than they reduce the prevalence of canine leishman iasis, a result that should encourage properly designed vector control trials. The second best strategy is to reduce susceptibility to leish maniasis by vaccinating people or dogs, or by eliminating childhood ma lnutrition where it is common. Both killing vectors and reducing susce ptibility (by whatever means) are more effective than killing dogs or treating them with drugs. In Europe, where vector control is less like ly to be successful and canine leishmaniasis is a major veterinary pro blem, a dog vaccine is highly desirable. Better drugs for dogs will he lp case management but, with regard to bringing down the incidence in the dog population, immunization is the ultimate goal.