title: Cryopreservation of Dirofilaria immitis microfilariae and third-stage larvae.
abstract: Microfilariae of Dirofilaria immitis retained their infectivity for susceptible mosquitoes after cooling to -196 degrees C in the presence of 5% dimethylsulphoxide (Me2SO) using a two-step cooling sequence. Motility and in vitro development of cryopreserved microfilariae also compared favourably with unfrozen controls. Third-stage larvae frozen by the same cooling sequence in the presence of either 5% Me2SO or 16% hydroxyethyl starch were motile upon thawing. Thawed larvae completed the third- to fourth-stage moult in vitro at a frequency approximately 5 to 10% of that seen in unfrozen controls.
mesh_terms: D000330:Aedes / Q000469:parasitology; D000818:Animals; D004183:Dirofilaria immitis / Q000254:growth & development / Q000472:pathogenicity / Q000502:physiology*; D005260:Female; D005370:Filarioidea / Q000502:physiology*; D005615:Freezing; D008842:Microfilariae / Q000254:growth & development / Q000472:pathogenicity / Q000502:physiology; D009068:Movement; D011309:Preservation, Biological