''Cystoisospora'' is a genus of parasitic

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

s belonging to the

phylum In biology, a phylum (; : phyla) is a level of classification, or taxonomic rank, that is below Kingdom (biology), kingdom and above Class (biology), class. Traditionally, in botany the term division (taxonomy), division has been used instead ...

Apicomplexa The Apicomplexa (also called Apicomplexia; single: apicomplexan) are organisms of a large phylum of mainly parasitic alveolates. Most possess a unique form of organelle structure that comprises a type of non-photosynthetic plastid called an ap ...

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 ...

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 ...

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 International_Code_of_Zoological_Nomenclature, 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 spe ...

of this genus is '' Cystoisospora felis''.

Life cycle

This parasite has been isolated from

dog The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the gray wolf. Also called the domestic dog, it was selectively bred from a population of wolves during the Late Pleistocene by hunter-gatherers. ...

cat The cat (''Felis catus''), also referred to as the domestic cat or house cat, is a small domesticated carnivorous mammal. It is the only domesticated species of the family Felidae. Advances in archaeology and genetics have shown that the ...

s and

raccoon The raccoon ( or , ''Procyon lotor''), sometimes called the North American, northern or common raccoon (also spelled racoon) to distinguish it from Procyonina, other species of raccoon, is a mammal native to North America. It is the largest ...

s. ''C. belli'' has been isolated from immunosuppressed humans — particularly those with

HIV The human immunodeficiency viruses (HIV) are two species of '' Lentivirus'' (a subgroup of retrovirus) that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the im ...

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 (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...

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 (American English), also spelled diarrhoea or diarrhœa (British English), is the condition of having at least three loose, liquid, or watery bowel movements in a day. It often lasts for a few days and can result in dehydration d ...

vomiting Vomiting (also known as emesis, puking and throwing up) is the 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, gastroenteritis, pre ...

fever Fever or pyrexia in humans is a symptom of an anti-infection defense mechanism that appears with Human body temperature, body temperature exceeding the normal range caused by an increase in the body's temperature Human body temperature#Fever, s ...

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 a lincosamide 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 (mi ...

toltrazuril Toltrazuril is an antiparasitic medication used primarily to treat coccidiosis in animals. Coccidiosis is a parasitic disease caused by coccidia, which are microscopic, spore-forming, single-celled obligate intracellular parasites belonging to ...

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