Studies on two new species of Microsporida hyperparasitic in adult Allocreadium fasciatusi (Trematoda, Allocreadiidae)

Abstract

SummaryThe vegetative and sporogonic stages of Unikaryon allocreadii sp. nov. and Nosema gigantica sp. nov., from the parenchyma of adult flukes, Allocreadium fasciatusi in the gut of the freshwater fish Aplocheilus melastigma from India, are described and figured. U. allocreadii, which is uninucleate throughout development and is disporoblastic, differs from U. legeri in that it occurs in adult flukes from a freshwater host. N. gigantica has diplokaryon nuclei, at least in the sporogonic stages, and is much larger than all other microsporidia in platyhelminths.Hatching of the spores and patholgenicity are described and the mode of transmission to the flukes is discussed. Infected flukes, which are sluggish and opaque, are often displaced from the normal site of infection.