Jump to navigation Jump to search

For patient information click here

Coccidia oocysts
Coccidia oocysts
Scientific classification
Kingdom: Protista
Phylum: Apicomplexa
Class: Conoidasida
Subclass: Coccidiasina
Order: Eucoccidiorida
Suborder, Family, Genera & Species


  • Adeleidae
  • Dactylosomatidae
  • Haemogregarinidae
  • Hepatozoidae
  • Karyolysidae
  • Klossiellidae
  • Legerellidae


  • Aggregatidae
    • Aggregata
    • Merocystis
    • Selysina
  • Calyptosporiidae
    • Calyptospora
  • Cryptosporidiidae
  • Eimeriidae
    • Atoxoplasma
    • Barrouxia
    • Caryospora
    • Caryotropha
    • Cyclospora
    • Diaspora
    • Dorisa
    • Dorisiella
    • Eimeria
    • Grasseella
    • Isospora
    • Mantonella
    • Ovivora
    • Pfeifferinella
    • Pseudoklossia
    • Tyzzeria
    • Wenyonella
  • Elleipsisomatidae
    • Elleipsisoma
  • Lankesterellidae
    • Lankesterella
    • Schellackia
  • Sarcocystidae
  • Selenococcidiidae
    • Selenococcidium
  • Spirocystidae
    • Spirocystis

WikiDoc Resources for Coccidia


Most recent articles on Coccidia

Most cited articles on Coccidia

Review articles on Coccidia

Articles on Coccidia in N Eng J Med, Lancet, BMJ


Powerpoint slides on Coccidia

Images of Coccidia

Photos of Coccidia

Podcasts & MP3s on Coccidia

Videos on Coccidia

Evidence Based Medicine

Cochrane Collaboration on Coccidia

Bandolier on Coccidia

TRIP on Coccidia

Clinical Trials

Ongoing Trials on Coccidia at Clinical

Trial results on Coccidia

Clinical Trials on Coccidia at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Coccidia

NICE Guidance on Coccidia


FDA on Coccidia

CDC on Coccidia


Books on Coccidia


Coccidia in the news

Be alerted to news on Coccidia

News trends on Coccidia


Blogs on Coccidia


Definitions of Coccidia

Patient Resources / Community

Patient resources on Coccidia

Discussion groups on Coccidia

Patient Handouts on Coccidia

Directions to Hospitals Treating Coccidia

Risk calculators and risk factors for Coccidia

Healthcare Provider Resources

Symptoms of Coccidia

Causes & Risk Factors for Coccidia

Diagnostic studies for Coccidia

Treatment of Coccidia

Continuing Medical Education (CME)

CME Programs on Coccidia


Coccidia en Espanol

Coccidia en Francais


Coccidia in the Marketplace

Patents on Coccidia

Experimental / Informatics

List of terms related to Coccidia

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]


Coccidia are microscopic, spore-forming, single-celled parasites belonging to the apicomplexan class Conoidasida.[1] Coccidian parasites infect the intestinal tracts of animals[2], and are the largest group of apicomplexan protozoa.

Coccidia are obligate, intracellular parasites, which means that they must live and reproduce within an animal cell.


Coccidiosis is the disease caused by coccidian infection. Coccidiosis is a parasitic disease of the intestinal tract of animals, caused by coccidian protozoa. The disease spreads from one animal to another by contact with infected feces, or ingestion of infected tissue. Diarrhea, which may become bloody in severe cases, is the primary symptom. Most animals infected with coccidia are asymptomatic; however, young or immuno-compromised animals may suffer severe symptoms, including death.

While coccidian organisms can infect a wide variety of animals, including humans and livestock, they are usually species-specific. One well-known exception is toxoplasmosis, caused by Toxoplasma gondii.

Coccidia in dogs

People often first encounter coccidia when they acquire a young puppy who is infected. The infectious organisms are canine-specific and are not contagious to humans (compare to zoonotic diseases).

Genera and species that cause coccidiosis

  • Genus Isospora is the most common cause of intestinal coccidiosis in dogs and cats and is usually what is meant by coccidiosis. Species of Isospora are species specific, meaning they only infects one type of species. Species that infect dogs include I. canis, I. ohioensis, I. burrowsi, and I. neorivolta. Species that infect cats include I. felis and I. rivolta. The most common symptom is diarrhea. Sulfonamides are the most common treatment. [3]
  • Genus Cryptosporidium contains two species known to cause cryptosporidiosis, C. parvum and C. muris. Cattle are most commonly affected by Cryptosporidium, and their feces are often assumed to be a source of infection for other mammals including humans. Recent genetic analyses of Cryptosporidium in humans have identified Cryptosporidium hominis as a new species specific for humans. Infection occurs most commonly in individuals that are immunocompromised, e.g. dogs with canine distemper, cats with feline leukemia virus infection, and humans with AIDS. Very young puppies and kittens can also become infected with Cryptosporidium, but the infection is usually eliminated without treatment.[3]
  • Genus Hammondia is transmitted by ingestion of cysts found in the tissue of grazing animals and rodents. Dogs and cats are the definitive hosts, with the species H. heydorni infecting dogs and the species H. hammondi and H. pardalis infecting cats. Hammondia usually does not cause disease.[3]
  • Genus Besnoitia infect cats that ingest cysts found in the tissue of rodents and opossum, but usually does not cause disease.[3]
  • Genus Sarcocystis infect carnivores that ingest cysts from various intermediate hosts. It is possible for Sarcocystis to cause disease in dogs and cats.[3]
  • Genus Toxoplasma has one important species, Toxoplasma gondii. Cats are the definitive host, but all mammals and some fish, reptiles, and amphibians can be intermediate hosts. Therefore, only cat feces will hold infective oocysts, but infection through ingestion of cysts can occur with the tissue of any intermediate host. Toxoplasmosis occurs in humans usually as low-grade fever or muscle pain for a few days. A normal immune system will suppress the infection but the tissue cysts will persist in that animal or human for years or the rest of its life. In immunocompromised individuals, those dormant cysts can be reactivated and cause many lesions in the brain, heart, lungs, eyes, etc. Without a competent immune system, the animal or human will most likely die from the infection. For pregnant women, the fetus is at risk if the pregnant woman becomes infected for the first time during pregnancy. If the woman had been infected during childhood or adolescence, she will have an immunity that will protect her developing fetus during pregnancy. The most important misconception about the transmission of toxoplasmosis comes from statements like 'ingestion of raw or undercooked meat, or cat feces.' Kitchen hygiene is much more important because people do tend to taste marinades or sauces before being cooked, or chop meat then vegetables without properly cleaning the knife and cutting board. Many physicians mistakenly put panic in their pregnant clients and advise them to get rid of their cat without really warning them of the likely sources of infection. Adult cats are very unlikely to shed infective oocysts. Symptoms in cats include fever, weight loss, diarrhea, vomiting, uveitis, and central nervous system signs. Disease in dogs includes a rapidly progressive form seen in dogs also infected with distemper, and a neurological form causing paralysis, tremors, and seizures. Dogs and cats are usually treated with clindamycin.[3]
  • Genus Neospora has one important species, Neospora caninum, that affects dogs in a manner similar to toxoplasmosis. Neosporosis is difficult to treat.[3]
  • Genus Hepatozoon contains one species that causes hepatozoonosis in dogs and cats, Hepatozoon canis. Animals become infected by ingesting an infected Rhipicephalus sanguineus, also known as the brown dog tick. Symptoms include fever, weight loss, and pain of the spine and limbs.

The most common medications used to treat coccidian infections are in the sulphonamide family. Although unusual, sulphonamides can damage the tear glands in some dogs, causing keratoconjunctivitis sicca, or "dry eye", which may have a life-long impact. Some veterinarians recommend measuring tear production prior to sulphonamide administration, and at various intervals after administration. Other veterinarians will simply avoid using sulphonamides, instead choosing another product effective against coccidia.

Left untreated, the infection may clear of its own accord, or in some cases may continue to ravage an animal and cause permanent damage or, occasionally, death.


  1. "The Taxonomicon & Systema Naturae" (Website database). Taxon: Genus Cryptosporidium. Universal Taxonomic Services, Amsterdam, The Netherlands. 2000. Unknown parameter |coauthors= ignored (help)
  2. "Biodiversity explorer: Apicomplexa (apicomplexans, sporozoans)". Iziko Museums of Cape Town.
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Ettinger, Stephen J.;Feldman, Edward C. (1995). Textbook of Veterinary Internal Medicine (4th ed. ed.). W.B. Saunders Company. ISBN 0-7216-6795-3.

See also

External links

cs:Kokcidie de:Kokzidien no:Koksidiose wa:Coccidiôze

Template:WikiDoc Sources