38th Annual Meeting of the Society for Invertebrate Pathology

Seasonal prevalence of microsporidian infections in Aedes mosquitoes reveals, that larvae with clear symptoms of infection detected from first registration of 3rd - 4th instar larvae and to the end of larvae development period, when mass pupation and imago hatching occur. As microsporidian infection resulted in retardation of development, the proportion of infected larvae increases while total number of 4th instar larvae decreases. Anopheles mosquitoes have 2 or 3 generations and infected larvae were registered in the first generation. The number of infection peaks coincides with the number of maximums of host population density. And the highest rates of infection were registered in the end of summer period because of accumulation of infection over the season. On the whole studying period several outbreaks of microsporidioses were registered. In 1976 Aedes mosquitoes larvae were almost totally infected by Amblyospora species with fatal consequences. In following years rates of infections decrease. In Anopheles populations with Parathelohania species infections in the 1980th also several epizooties were registered. However, during last years we registered approximately equal levels of infections independently of numbers of host species. In Anopheles populations with Parathelohania sp. infection rates varied from 0.1 to 1.6%, in Aedes populations with Amblyospora infections from 0.1 to 6.5 %.