The pathology of lymphoreticular and genital tissues of silvered leaf monkeys (Presbytis cristata) experimentally infected with Wuchereria bancrofti.

The discovery of the silvered leaf monkey, Presbytis cristata, as a suitable experimental host for the human filarial parasite, Wuchereria bancrofti, opened the door for major advances in our understanding of the disease caused by this parasite. To study the pathogenesis of bancroftian filariasis in this model, 15 adult P. cristata which had been experimentally infected with 250 infective third-stage larvae of the parasite were examined. After inoculation with larvae, the monkeys were maintained under study for periods of 2 to 3 years, at which time all had achieved patent infections. At necropsy, Wuchereria-induced macroscopic lesions were not detected in experimentally infected monkeys. Microscopic findings included nematodiasis, microfilariasis, lymphadenitis, lymphangiectasis, perilymphangitis, splenitis, orchitis, periorchitis, epididymitis and funiculitis. Sections of normal adult worms were most often found in lymphatic vessels near lymph nodes, or in the lymphatics of the male genital system. These worms caused microfiliariasis in some regional lymph nodes. Inflammatory responses to filariae were most prominent in proximity to degenerated and dead worms, whereas intact, normal appearing adult worms elicited only minimal cellular response.