''Cystoisospora canis'', previously known as ''Isospora canis'', is a microscopic,

coccidia Coccidia (Coccidiasina) are a subclass of microscopic, spore-forming, single-celled obligate intracellular parasites belonging to the apicomplexan class Conoidasida. As obligate intracellular parasites, they must live and reproduce within an a ...

parasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...

that causes an intestinal tract infection in dogs. The intestinal tract infection is

coccidiosis 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 ...

caused by a

protozoa Protozoa (singular: protozoan or protozoon; alternative plural: protozoans) are a group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic tissues and debris. Histo ...

(one-celled organisms) called ''coccidia''.

Background

Cystoisospora ''Cystoisospora'' is a genus of parasitic alveolates belonging to the phylum 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 sp ...

'', previously known ''

Isospora ''Isospora'' is a genus of internal parasites in the subclass Coccidia. It is responsible for the condition isosporiasis, which causes acute, non-bloody diarrhoea in immunocompromised individuals. Taxonomy At least 248 species were originally ...

'', is a genus that causes coccidiosis in humans, dogs and cats. Coccidiosis is multiple gastrointestinal infections caused by members of the sporozoan parasite coccidium which includes ''Cystoisospora''. Species that can infect dogs are ''Cystoisospora canis'', ''Cystoisospora ohioensis'', ''Cystoisospora neorivolta'', and ''Cystoisospora burrowsi''. ''C. Canis''

oocysts Apicomplexans, a group of intracellular parasites, have Biological life cycle, 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 a ...

are larger in size compared to the other three and the other three are structurally similar to each other but not with ''C. Canis'', making it easy to identify. ''C. ohioensis'', ''C. burrowsi'', and ''C. neorivolta'' oocysts are similar in structure so they cannot be distinguished from each other until further diagnosis.

Life cycle and transmission

For a dog to become infected, the dog has to have ingested

that can be found in fecal material or another host animal. When a dog is infected, the parasite can be found in the small intestinal epithelium which are the cells that line the cavity of the small intestine. It can also be found in tissues such as spleen, liver, and mesenteric lymph nodes (located in the walls of the intestines). Sporulated oocyst then releases 8

sporozoite 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. These sporozoites attack the

intestinal epithelial cells The intestinal epithelium is the single cell layer that form the luminal surface (lining) of both the small and large intestine (colon) of the gastrointestinal tract. Composed of simple columnar epithelial cells, it serves two main functi ...

where they develop into a

schizont 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 ...

. Schizonts are part of the asexual stages where there are three generations of schizonts. After the last part of the multiplication process, gametes are formed.

Gametes A gamete (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. In species that produce t ...

are part of the sexual stages, and they can invade other cells. Male gametes divide and break out to the host cell, then go invade cells containing the female gamete. Once the male gametes and the female gamete are in the same host cell, they will fuse creating a

zygote A zygote (, ) is a eukaryotic cell formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information of a new individual organism. In multicellula ...

. The

develops into an oocyst. The oocyst then breaks out of the host cell and leaves the host through its feces. The oocyst are noninfectious in the feces but will sporulate in 4 days becoming infectious for the next host and for the cycle to begin again.Nolan. 2004, January 1). Adult Parasite:. Retrieved December 7, 2014, from The clinical signs associated with ''Cystoisospora canis'' are severe when the oocysts ingested are sporulated instead of being ingested unsporulated.

Clinical signs

Coccidiosis is not usually a great threat to the dog’s health unless the dog is weak or has a low immune system.Isospora spp., Isospora canis, Isospora felis. (n.d.). Retrieved December 4, 2014, from In some cases infection is

asymptomatic In medicine, any disease is classified asymptomatic if a patient tests as carrier for a disease or infection but experiences no symptoms. Whenever a medical condition fails to show noticeable symptoms after a diagnosis it might be considered asy ...

this is generally the case for adult dogs. In other cases mostly found in puppies and older dogs the coccidial parasite can cause anemia, weight loss, abdominal pain, vomiting, anorexia, watery diarrhea, fever, dehydration, and mental depression. If left untreated it can lead to the death of the infected dog.

Diagnosis

The time between infection and when the parasite can be detected (the prepatent period) is about 9–11 days. To detect the parasite, a

fecal flotation Feces ( or faeces), known colloquially and in slang as poo and poop, are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the large intestine. Feces contain a relat ...

examination is performed. This examination is where a sample of stool is examined under a microscope to see if there are parasites present.

Treatments

Antibiotics An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention o ...

can decrease the presence of the parasites and restores the dog’s health. The antibiotics should be taken for 10 to 14 days. Some of the antibiotics include

sulfadimethoxine Sulfadimethoxine (or sulphadimethoxine, trade names Di-Methox or Albon) is a long-lasting sulfonamide antimicrobial medication used in veterinary medicine. It is used to treat many infections, including respiratory, urinary tract, enteric, and so ...

and

amprolium Amprolium is the organic compound sold as a coccidiostat used in poultry. It has many International Nonproprietary Names. __TOC__ Uses in coccidiosis treatment in poultry The drug is a thiamine analogue and blocks the thiamine transporter of ''E ...

Prevalence

Coccidia Coccidia (Coccidiasina) are a subclass of microscopic, spore-forming, single-celled obligate intracellular parasites belonging to the apicomplexan class Conoidasida. As obligate intracellular parasites, they must live and reproduce within an a ...

is found in 3% to 38% of dogs in North America.CAPC. (2014, January 1). Coccidia Prevalence. Retrieved December 7, 2014, from http://www.capcvet.org/capc-recommendations/coccidia-prevalence

Control and prevention

To prevent coccidia, sanitation is key to make sure the environment is free of feces. Rapid removal of feces is important because ''C. Canis'' can develop quickly into the infectious stages of its life cycle. Mature oocysts are resistant to most cleaning products and can live for long periods of time. Using stronger cleaning products that contain ammonia or steam cleaning will kill the infectious oocysts. Another way to prevent infection is to not let the dog ingest rodents which could be carrying the parasites.

References

{{Taxonbar, from=Q20686398 Conoidasida