''Cystoisospora'' is a genus of parasitic

alveolate The alveolates (meaning "pitted like a honeycomb") are a group of protists, considered a major clade and superphylum within Eukarya. They are currently grouped with the stramenopiles and Rhizaria among the protists with tubulocristate mitocho ...

s belonging to the

phylum In biology, a phylum (; plural: phyla) is a level of classification or taxonomic rank below kingdom and above class. Traditionally, in botany the term division has been used instead of phylum, although the International Code of Nomenclature ...

Apicomplexa The Apicomplexa (also called Apicomplexia) are a large phylum of parasitic alveolates. Most of them possess a unique form of organelle that comprises a type of non-photosynthetic plastid called an apicoplast, and an apical complex structure. Th ...

Taxonomy

This genus was originally created by J. K. Frenkel in 1977. Its use was discontinued but was resurrected in 2005. This genus currently includes species that have

oocyst Apicomplexans, a group of intracellular parasites, have life cycle stages that allow them to survive the wide variety of environments they are exposed to during their complex life cycle. Each stage in the life cycle of an apicomplexan organism is ...

s containing two sporocysts with four sporozoites in each without Stieda bodies. These species infect the

enterocyte Enterocytes, or intestinal absorptive cells, are simple columnar epithelial cells which line the inner surface of the small and large intestines. A glycocalyx surface coat contains digestive enzymes. Microvilli on the apical surface increase i ...

s of mammals and are transmitted by the orofaecal route. DNA analysis has shown that this genus belongs to the family ''

Sarcocystidae The Sarcocystidae are a family of Apicomplexa associated with a variety of diseases in humans and other animals. Taxonomy Genera in this family include: * ''Besnoitia'' * '' Cystoisospora'' * '' Frenkelia'' * '' Nephroisospora'' * ''Neospora'' ...

''. The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specim ...

of this genus is '' Cystoisospora felis''.

Life cycle

This parasite has been isolated from dogs,

cat The cat (''Felis catus'') is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members of ...

s and

raccoon The raccoon ( or , ''Procyon lotor''), sometimes called the common raccoon to distinguish it from other species, is a mammal native to North America. It is the largest of the procyonid family, having a body length of , and a body weight of ...

s. ''C. belli'' has been isolated from immunosuppressed humans — particularly those with HIV infection. These parasites normally infect the

s of the

small intestine The small intestine or small bowel is an organ (anatomy), organ in the human gastrointestinal tract, gastrointestinal tract where most of the #Absorption, absorption of nutrients from food takes place. It lies between the stomach and large intes ...

and are spread by the orofaecal route. The definitive hosts are cats but other species including various species of

rodent Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are n ...

s may be infected. No further development occurs in these paratenic hosts and the parasites remain dormant until ingested by a definitive host.

Epidemiology

This genus has been recorded worldwide. ''C. felis'' and ''C. rivolta'' occur in up to 40% of cats in some tropical countries.

Clinical

Clinical signs include watery

diarrhea Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin w ...

vomiting Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose. Vomiting can be the result of ailments like food poisoning, gastroenter ...

fever Fever, also referred to as pyrexia, is defined as having a temperature above the normal range due to an increase in the body's temperature set point. There is not a single agreed-upon upper limit for normal temperature with sources using val ...

and weight loss. The diagnosis is made by microscopic examination of the stool. Distinguishing between the species of ''Cystoisospora'' is most easily done with PCR. This method can also be used to make the diagnosis. Treatment is based on trimethoprim-sulfonamides with

clindamycin Clindamycin is an antibiotic medication used for the treatment of a number of bacterial infections, including osteomyelitis (bone) or joint infections, pelvic inflammatory disease, strep throat, pneumonia, acute otitis media (middle ear in ...

toltrazuril Toltrazuril is a coccidiostat. See also * Clazuril * Diclazuril Diclazuril (trade name Vecoxan) is a coccidiostat. See also * Clazuril * Ponazuril * Toltrazuril References Antiparasitic agents Nitriles Chlorobenzenes Triaz ...

for resistant strains.

Prevention

Hygiene on the premises is important in prevention. Good litter tray hygiene is also critical in multi-cat households. Utensils, runs, cages and other implements should be steam-cleaned or washed in boiling water. Because of the importance of paratenic hosts such as cockroaches, insect control is critical.

References

{{Taxonbar, from=Q5201274 Apicomplexa genera