Studies on Microfilaremia in Dogs

Abstract

SummaryExperiments were designed to search for mechanisms responsible for the maintenance of stable populations of microfilariae. Brugia pahangi and Dirofilaria immitis infections in dogs were chosen for the study. Results of experiments showed that: (1) Microfilariae transfused into uninfected dogs circulated for several weeks. The rate of recovery was greatest in a splenectomized recipient and least in a dog to which a transplanted adult worm had been given. (2) Splenectomy had no effect on the levels of microfilaremia in dogs infected with D. immitis. (3) Neither the addition of microfilariae (by transfusion) nor the removal of microfilariae (by withdrawal of large quantities of blood) caused any permanent alteration of the original levels of microfilaremia. Though the exact controlling mechanism(s) remains obscure, this study supports the view that the maintenance of stable populations of microfilariae is a manifestation of successful inter-adaptation between the filarial parasite and its host.