The microsporidians are another recent addition to the Kingdom Fungi. They are all intracellular parasites of animals or protists, mainly affecting invertebrates. They do not have mitochondria, but they do have mitosomes. The presence of mitosomes, along with other fungal characteristics, distinguishes this group. Microsporidians have no means of locomotion and are able to form spores that can live outside of the host cell for long periods of time.
Human microsporidiosis is an emergent human disease that usually only affects people with compromised immune systems. People with conditions like AIDS are susceptible to microsporidiosis.
More commonly, microsporidians infect invertebrate animals such as insects. For example, the microsporidian Nosema ceranae is linked to the population declines of honeybees. However, we might be able to use the parasitic abilities of microsporidians to our advantage - there is currently research under way to see if a mosquito-specific microsporidian could be used as a way to control the spread of malaria.