Horizontal transmission of Amblyospora albifasciati Garcia and Becnel, 1994 (Microsporidia : Amblyosporidae), to a copepod intermediate host and the neotropical mosquito, Aedes albifasciatus (Macquart, 1837)

The life cycle of Amblyospora albifasciati is characterized by three sporul ation sequences involving the definitive mosquito host and a copepod interm ediate host. Meiospores of A albifasciati were infectious per os to adult f emales of the copepod Mesocyclops annulatus. All developmental stages in th e 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, we re large, pyriform, and measured 10.4 x 4.8 mu m. They infected Aedes albif asciatus larvae when ingested to initiate a sequence that involves schizogo ny and gametogony and ends with plasmogamy and nuclear association to form diplokaryotic meronts. Oval binucleate spores (9.3 x 3.1 mu m) are formed i n the adult mosquito and are responsible for vertical transmission to the f ilial generation. (C) 2000 Academic Press.