Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 26, 1997
Publication Date: N/A
Interpretive Summary: Infectious agents, known as microsporidia, are being evaluated for use in the biological control of insects. One microsporidium that is being investigated is a potential biological control agent of the Yellow Fever Mosquito Aedes aegypti. Although this microsporidium is undergoing extensive evaluation, its complete life cycle is not completely understood. This investigation examines the early development of the parasite in its host mosquito. As a result of this study, a previously undescribed sporulation sequence was discovered, thereby completing the life cycle of E. aedis. New information obtained by scientists at the Center for Medical, Agricultural and Veterinary Entomology contributes to our basic understanding of the biology of microsporidia and will contribute to the fundamental knowledge of this, and other microsporidia. At this point, the primary user of this knowledge will be other researchers working on microsporidia as biological control agents of insects that vector human disease.
Technical Abstract: The presence of a previously unrecognized sporulation sequence during the early development of the microsporidium Edhazardia aedis is described from the mosquito, Aedes aegypti. This new information, together with the previous data on this species, has established that the developmental cycle of E. aedis is characterized by 4 sporulation sequences; two in the parental host and two in the filial generation. This is the first report of a microsporidium exhibiting 4 sporulation sequences. The events of gametogony, plasmogamy, nuclear association, and merogony occur almost exclusively in the gastric caeca following the initial infection and culminates with the formation of a first binucleate spore. This spore is morphologically, ultrastructurally, temporally and functionally different from the second binucleate (transovarial) spore. Our findings suggest that the first binucleate spore is responsible for autoinfection and its descendants lead to the formation of the second binucleate spore.