Coccidia

Coccidia, or Coccidiasina, are parasitic protozoans, a subclass of microscopic, spore forming, single celled obligate intracellular parasites belonging to the apicomplexan class Conoidasida, and they represent the largest group of apicomplexan protozoa. As obligate intracellular parasites they must live and reproduce inside animal cells, and they infect the intestinal tracts of a wide range of hosts, including all mammals and some birds, fish, reptiles and amphibians. Infection with coccidia is called coccidiosis, and most coccidian species infect only one type of host, with the notable exception of Toxoplasma gondii, which can infect all mammals though it reproduces sexually only in cats. Depending on the species, coccidiosis can cause fever, vomiting, diarrhea, muscle pain and nervous system effects and can be fatal, and while healthy adult animals may recover without treatment, immunocompromised individuals and young animals usually need medication to survive, and humans are generally infected by eating undercooked meat, though Toxoplasma gondii can also spread through poor hygiene around infected cat feces.