Virus-like particles in an antarctic Aggregata sp.: I. Sporogonial stages

An unknown Aggregata sp. was found in the renal organ of an antarctic Benthoctopus sp., when it was inspected for the presence of dicyemid mesozoans. Merozoites invaded the renal epithelium, whereas sporogonial stages resided in the submucosal connective tissue. Interestingly, individuals of all developmental stages were found to be infected with hitherto unknown virus-like particles. These virus-like particles, spherical in shape, nonenveloped and measuring approximately 30 nm in diameter, could be observed in the nuclei as well as within the cytoplasm. Greater amounts of virus-like particles tended to be arranged in paracrystalline arrays. Although the infection was extensive, it obviously had no pathogenic effect on the parasites themselves. On the basis of the host specificity, size, morphology and histochemical analysis, which suggested the putative viral genome as RNA, a relationship with Totoviridae is assumed.