Coelomomyces infection of the adult female mosquito Aedes trivittatus (Coquillett) in Manitoba

Adult females of Aedes trivittatus collected near Winnipeg, Manitoba, were found to be infected with a Coelomomyces sp. The level of infection, as expressed by the formation of sporangia within the haemocoel of the adult, was as high as 56% in blood-fed female mosquitoes. No sporangia were found in females or males that were fed only carbohydrates. Mature sporangia were visible through the abdominal wall of the infected adult at time of death. None of the infected females was able to reproduce. Coelomomyces infection was found to be initiated during the fourth larval instar and (or) pupal stage in artificial pools. Two species of copepods were present in the pools; however, the role of these organisms in the life cycle of the Coelomomyces sp. is not known at this time.