title: Cryopreservation of the microfilariae of Brugia malayi, Dirofilaria corynodes, and Wuchereria bancrofti.
abstract: Methods are presented for the cryopreservation of a sheathed microfilaria, Brugia malayi, and an unsheathed species, Dirofilaria corynodes. The former survived best when frozen at the rate of -0.8 degree or -0.5 degree C per minute using 9% dimethyl sulfoxide (DMSO) as the cryopreservative. Approximately 52-79% of the thawed microfilariae developed to the third stage in Aedes aegypti mosquitoes versus 79% of the unfrozen specimens. For D. corynodes the optimum freezing rate was -2 degrees or -5 degrees C per minute, and 6% DMSO combined with 0.004 M polyvinylpyrrolidone (PVP) afforded the best cryoprotective effect. The development of thawed microfilariae in mosquitoes ranged from 22-32% versus 29% for unfrozen specimens. In general, the viability of both species of microfilaria was retained best when stored in liquid nitrogen (-196 degrees C). The entire life cycle of B. malayi was completed in the laboratory using cryopreserved microfilariae as the initial source. The cryopreservation of Wuchereria bancrofti also is discussed.
mesh_terms: D000330:Aedes / Q000469:parasitology; D000818:Animals; D002009:Brugia / Q000254:growth & development; D004121:Dimethyl Sulfoxide; D004182:Dirofilaria / Q000254:growth & development; D004901:Erythrocebus patas; D005368:Filariasis / Q000469:parasitology; D005370:Filarioidea / Q000254:growth & development; D005615:Freezing; D008842:Microfilariae / Q000254:growth & development; D010274:Parasitology / Q000379:methods*; D011309:Preservation, Biological; D014957:Wuchereria / Q000254:growth & development
chemical_list: D004121:Dimethyl Sulfoxide