AN IN VIVO METHOD FOR THE SCREENING OF ANTIFILARIAL AGENTS USING SETARIA CERVI AS TEST ORGANISM

[摘要] References(12)Cited-By(12)Setaria cervi (1, 2), a cosmopolitan nematode parasite of cattle, lives in the peritoneal cavity. 85% of cattle are found infected with Setaria cervi. The maximum number of worms (60 to 70 in each head) is found between mid June to August after which the number declines and from December to January incidence is as low as 10 to 20 Setaria cervi per head. From February onwards the number starts increasing. The ratio of male and female Setaria cervi in cattles has been found to be 1 : 1.21, but incidence of infection in these animals is very low. Setaria cervi has been found to be more common in goats and sheep and Setaria cervi in horses. No report is however available regarding the incidence of infection by Setaria cervi in neighbouring countries. Little is known about the life history and mode of transmission, but a blood sucking arthopod vector is presumed to be involved in the completion of the life cycle. Williams (3) succeeded in transplanting these worms from freshly slaughtered cattle to rabbits and showed the presence of microfilariae in the peripheral circulation of the rabbits. Although Williams (3) did not succeed in finding an arthopod vector, his results indicated the possibility of keeping the nematodes alive in an experimental host. Later, Nelson (4) succeeded in transplanting both adult worms and microfilariae to rabbits and monkeys. The morphology of the adult worm and microfilaria is described by Ansari (5). Adult worms measure 10.0±2.5 cm (male) and 15.0±2.0 cm (female) in length. The microfilariae are microscopic structures 277±14.0 μ long and 7.5±1.5 μ wide. Ansari (6) successfully implanted the adult worms intraperitoneally in rats and studied microfilariae periods in the peripheral circulation. Maximum density of the microfilariae in the peripheral blood occurred between 6-8 a.m. and 6-8 p.m. Singhal et al. (7) also successfully transplanted the adult worms of Setaria cervi intraperitoneally in rats and reported disappearance of microfilariae from the peripheral circulation after oral administration of diethylcarbamazine. In the present study an attempt has been made to extend these observations and to establish the value of Setaria cervi as a test organism for the screening of antifilarial agents.

[学科分类] 药理学