[Experiments in vitro with Litomosoides carinii (Nematoda: Filarioidea). I. Maintenance of adult females and microfilariae as well as release of microfilariae in different culture media (author's transl)].

Embryos of L. carinii continue intrauterine development to microfilariae and are totally released into the medium within 5--6 days when the latter (Tc 199) is changed daily and air is used as the gas phase. Oogenesis or further fertilization of eggs, however, does not occur in vitro in any of the media examined by us. One female releases 140 X 10(3) microfilaria/day on an average in vitro within 5--6 days. Mean initial numbers of 300 X 10(3) Mf/female/day are observed. Addition of equine serum inhibits microfilarial release in vitro; normal cotton rat serum prolongs survival of females while total numbers of released microfilariae or retained embryonic stages are not increased. The serum of post-patent animals does not influence the numbers of released microfilariae or their viability or survival of females. Microfilariae released in vitro in Tc 199 + 33% normal cotton rat serum survive for more than 8 days, when air is used as the gas phase and the medium is changed daily. Microfilariae isolated from the blood of patent animals survive for at most 6 days, at a 48-hourly change of medium survival does not even exceed 4 days.