microsporidium infecting anopheles superpictus (diptera: culicidae) larvae

background: microsporidia are known to infect a wide variety of animals including mosquitoes (diptera: cu­licidae). in a recent study on the mosquito fauna of chahar mahal and bakhtiari province, at the central western part of iran, a few larvae of anopheles superpictus were infected with a microsporidium-resembled microorganism. cur­rent investigation deals with the identification of the responsible microorganism at the genus level. methods: fresh infected larvae were collected from the field. after determining the species identity they were dis­sected to extract their infective contents. wet preparations were checked for general appearance and the size of the pathogenic microorganism. fixed preparations were stained with geimsa and ryan-blue modified trichrome tech­niques to visualize further morphological characters. the obtained light microscopy data were used in the identifica­tion process. results: the infected larvae were bulged by a whitish material filling the involved segments corresponding to a microsporidium infection. bottle-shaped semioval spores ranged 4.33±0.19×2.67±0.12 and 4.18±0.43×2.45±0.33 micron in wet and fixed preparations, respectively. they were mostly arranged in globular structures comprised of 8 spores. these data was in favor of a species from the genus parathelohania in the family ambliosporidae. conclusion: this is the first report of a microsporidium infection in an. superpictus . the causative agent is diag­nosed as a member of the genus parathelohania . further identification down to the species level needs to determine its ultrastructural characteristics and the comparative analysis of ss rrna sequence data. it is also necessary to un­derstand the detail of the components of the transmission cycle.