THE BIOLOGY OF EXPERIMENTAL DIPETALONEMA RECONDITUM INFECTIONS IN BEAGLES

Methods of laboratory maintenance of experimental Dipetalonema reconditum infections in dogs were studied. Patent infections were produced in eight of eleven dogs inoculated with 20-123 infective larvae. Prepatent periods varied between 66-101 days and maximum microfilaremias ranged from 10-1160 microfilariae (mf) per ml. Duration of patency varied between 138 and >555 days. Patent infections were not established in two cats and six Mongolian jirds each inoculated with 22-25 infective larvae.;Mean microfilaremias of orally-inoculated dogs were significantly greater than those of subcutaneously-inoculated dogs 18-28 wk PI. No microfilariae were detected at any time in dogs treated with diethylcarbamazine and ivermectin as a preventative. Ivermectin as a microfilaricide was 96.2-99.8% effective against D. reconditum microfilariae on days 1, 2, 3 and 6 post treatment.;Occult dipetalonemiasis was suspected in eight dogs. Therefore, four of these dogs were treated with prednisone in order to induce microfilaremias, and four dogs served as untreated controls. Microfilaremias did not increase in treated dogs even though steroid-induced effects of neutrophilia, lymphopenia and eosinopenia were evident when compared to untreated dogs.;Four of five dogs with chronic infections had eosinophilia and one had lymphocytosis. Three of four dogs examined had proteinuria.;Clinical pathology, oral transmission and chemotherapy of experimental dipetalonemiasis were studied in 39 Beagles. Mean total leukocyte counts were significantly (P < 0.05) greater in inoculated than in uninoculated control dogs at 4, 5 and 7-12 wk PI, and mean eosinophil counts were significantly greater 3-11, 13-15, 20 and 23-24 wk PI. Mean values for the remaining hematologic tests, weights, serum biochemistries and urinalyses were not significantly different between inoculated and uninoculated dogs during the study. A total of one male worm was recovered at necropsy.;These results warrant further investigation into the potential significance of canine dipetalonemiasis in veterinary medicine.