''Cystoisospora'' is a genus of parasitic

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

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 f ...

Apicomplexa.

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 i ...

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 its ...

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

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 wolf. Also called the domestic dog, it is derived from the extinct Pleistocene wolf, and the modern wolf is the dog's nearest living relative. Do ...

s, cats and raccoons. ''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 immune ...

infection. These parasites normally infect the

s of the

small intestine The small intestine or small bowel is an organ in the gastrointestinal tract where most of the absorption of nutrients from food takes place. It lies between the stomach and large intestine, and receives bile and pancreatic juice through the p ...

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 na ...

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 wi ...

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 Human nose, nose. Vomiting can be the result of ailments like Food-poisoning, foo ...

fever Fever, also referred to as pyrexia, is defined as having a body temperature, temperature above the human body temperature, normal range due to an increase in the body's temperature Human body temperature#Fever, set point. There is not a single ...

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 PCR or pcr may refer to: Science * Phosphocreatine, a phosphorylated creatine molecule * Principal component regression, a statistical technique Medicine * Polymerase chain reaction ** COVID-19 testing, often performed using the polymerase chain r ...

. 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 infec ...

toltrazuril Toltrazuril is a coccidiostat. See also * Clazuril * Diclazuril * Ponazuril Ponazuril ( INN), sold by Merial, Inc., now part of Boehringer Ingelheim, under the trade name Marquis® (15% w/w ponazuril), is a drug currently approved for the tre ...

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