title: Survival and infectivity of Brugia malayi microfilariae after cryopreservation.
abstract: Methods were studied for the cryopreservation of microfilariae of periodic Brugia malayi. RPMI-1640 tissue culture medium containing 6% dimethyl sulfoxide (DMSO) and 15% newborn calf serum was used as cryoprotectant. Samples were frozen slowly in the vapor phase of liquid nitrogen prior to emersion in liquid nitrogen (-196 degrees C). The freezing rate was -0.5 to -1.0 degrees C per minute, microfilariae remained viable for as long as, 212 and 375 days, survival rates were 94 to 98% and they were infective to Aedes togoi mosquitos. The infective larvae (L3) were obtained for 10-11 days after feeding at 28 degrees C room-temperature and the infection rate of L3 in test mosquitos was 22.4-30.6%. All DMSO should be removed from the freezing medium to restore microfilariae activity after freezing.
authors.affiliation: Guizhou Provincial Institute of Parasitic Diseases, Guiyang, People's Republic of China.
authors.forename: S H
authors.initials: SH
authors.lastname: Wang
authors.forename: H J
authors.initials: HJ
authors.lastname: Zheng
mesh_terms: D000330:Aedes / Q000469:parasitology*; D000818:Animals; D002009:Brugia / Q000502:physiology*; D016009:Chi-Square Distribution; D015925:Cryopreservation / Q000379:methods; D004121:Dimethyl Sulfoxide; D006801:Humans; D008842:Microfilariae / Q000472:pathogenicity; D009584:Nitrogen
chemical_list: D009584:Nitrogen; D004121:Dimethyl Sulfoxide