Dirofilaria aethiops Webber, 1955, a filarial parasite of monkeys II. Maintenance in the laboratory

Abstract

1. An account is given of the stages of the life history of Dirofilaria aethiops which take place in the monkey and of the transmission of the infection in the laboratory.2. The microfilariae exhibit nocturnal periodicity in the blood; the number of microfilariae at midday was usually less than 1% of the number at midnight.3. Aëdes aegypti mosquitoes were fed on monkeys during the evening when there were many microfilariae in the blood. Larvae developed in these mosquitoes and they were ultimately transferred to fresh monkeys by injection of a saline suspension of mosquitoes and infective larvae. In this way six Cercopithecus aethiops and one Macaca mulatto, monkey were successfully infected; seven other Cercopithecus aethiops, one Cebus apella, and one Cercocebus monkey were inoculated, but the worms failed to establish themselves.4. In the infected monkeys microfilariae appeared in the blood 11 months after the injection of infective larvae. The number of microfilariae then increased for 8–12 months. Subsequently, it decreased to one-tenth of the maximum in 2 years from the first appearance.5. Post-mortem examination showed that the adult worms live in the fascial tissues on or between the muscle bundles, especially those of the thighs. Tissue reaction to the worms is slight and in these monkeys there was no other pathogenic effect of the infection.6. Adult worms from three of the monkeys were transplanted to two normal monkeys. Microfilariae were found in the blood of one of these and persisted for over 2 years.