The Suppression ofPlasmodium bergheiinAnopheles coluzziiinfected later withVavraia culicis

Abstract

AbstractThe suppression of malaria parasites in the presence of an existing microsporidian infection ofVavraia culicis, was examined using fluorescentPlasmodium berghei. Younger hosts infected withV. culicishad a greater suppressive effect on the subsequent development ofP. bergheithan older infected hosts. This effect was density dependant on the numbers of microsporidian spores present, consequently it was also dependant on the age at which mosquitoes were infected with microsporidia, as larvae infected later harboured comparatively fewerV. culicisspores. The timing of primary and secondary infections of larval and adult mosquitoes (host age) with different parasites affects parasite development and hence disease outcomes. The use of green fluorescentP. bergheienabled easier and rapid visualisation and separation of malaria oocysts fromV. culicisspores. Different degrees of melanisation ofV. culicisspores was seen in a number of hosts and merits further investigation.