Nosema is a genus of microsporidian parasites. Vairimorpha is a genus of microsporidian parasites. Loma is a genus of microsporidian parasites, infecting fish. Glugea is a genus of microsporidian parasites, predominantly infecting fish. "B. bimaculatus" can be infected with "Nosema bombi", a microsporidian. It was originally used against microsporidian parasites "Nosema apis" infections in honey bees. "E. nucleophila" is a microsporidian, a group of intracellular parasites related to fungi. This outcome is due to the microsporidian parasite proliferating inside the host cell. Microsporidian infections of humans sometimes cause a disease called microsporidiosis. The genus name "Orthosoma" was also previously used for a microsporidian genus. Microsporidian xenomas that develop in fish can also occur in crustaceans. Compared to smaller microsporidian genome, Gene density is rather low in "H. tvaerminnensis" but variable. It is suggested that "H. tvaerminnensis" genome is the largest known microsporidian genome. Enterospora nucleophila is a microsporidian infecting the gilt-head bream ("Sparus aurata"). At least 14 microsporidian species, spread across eight genera, have been recognized as human pathogens.