Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/2/1999
Publication Date: N/A
Interpretive Summary: Naturally occurring protozoan parasites (Microsporidia) of mosquitoes are under study by USDA/ARS scientists at the Center for Medical, Agricultural and Veterinary Entomology in Gainesville Florida to evaluate and develop these disease causing organisms as biological control agents. Microsporidian parasites are known to cause mortality in mosquitoes worldwide and recent advances on fundamental aspects of their life cycles and modes of transmission has led to renewed interest in these pathogens as microbial control agents. This article, using both the light and electron microscope, describes the complete life cycle of a new microsporidian parasite in a mosquito host and documents the involvement of a copepod intermediate host. New information obtained here contributes to our basic understanding of these parasites which we hope will assist in the evaluation and development of microsporidia as biocontrol agents.
Technical Abstract: The life cycle of Amblyospora albifasciati is characterized by three sporulation sequences involving the definitive mosquito host and a copepod intermediate host. Meiospores of A. albifasciati were infectious per os to female adults of the copepod Mesocyclops annulatus. All developmental stages in the copepod had unpaired nuclei, with sporulation involving the formation of a sporontogenic interfacial envelope and the production of a second type of uninucleate spore. These spores, formed in the ovaries of M. annulatus, were large, pyriform, and measured 10.4 x 4.8 micrometers. They infected Aedes albifasciatus larvae when ingested to initiate a sequence that involves schizogony and gametogony and ends with plasmogamy and nuclear association to form diplokaryotic meronts. Oval binucleate spores (9.3 x 3.1 micrometers) are formed in the adult mosquito and are responsible for vertical transmission to the filial generation.