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Basics ⬇

Outline

BASICS

Overview!!navigator!!

  • Cryptosporidiosis is a zoonosis affecting a variety of species of animals including humans. Cryptosporidia are now recognized to be a major waterborne parasite worldwide
  • Cryptosporidium is an apicomplexan parasite in the order Eucoccidiorida
  • Reported prevalence in nondiarrheic horses ranges from 0% to 23% with a peak reported at 5–8 weeks of age
  • Little is known about the specific pathogenicity
  • The syndrome has a range of presentations from asymptomatic shedding of oocysts in feces to severe disease
  • In foals pathogenicity is not clear and cryptosporidia-associated diarrhea in foals has mostly been described in immunodeficient foals
  • Horse infection is by ingestion of Cryptosporidium oocytes
  • In most species cryptosporidia infect ileal and proximal colonic epithelial cells, often resulting in impaired absorption and increased secretion (clinically observed mostly as diarrhea)
  • Cryptosporidia life cycle has 6 phases, which are completed within same host and may result in persistent chronic infection (auto-reinfection)
  • In a few genotyping studies in foals C. parvum was the most common strain
  • In several species cryptosporidiosis is an emerging disease, but the reason for this is unclear
  • It is not a very significant pathogen and seems to be associated with co-infections in foals with diarrhea

Signalment!!navigator!!

  • Clinically affected foals are often immunocompromised regardless of breed and sex. Common in foals with severe combined immunodeficiency
  • Malodorous diarrhea; mild depression, thin body condition, no overt clinical signs

Causes and Risk Factors!!navigator!!

  • C. parvum—horse-adapted cryptosporidium (rare); overcrowding; part of the foal diarrhea complex
  • Infection via fecal–oral route (zoonosis); incubation period not very well established in foals (in humans, variable: 1–12 days, with an average of 7 days)
  • Poor hygiene management

Diagnosis ⬆ ⬇

Outline

DIAGNOSIS

Sucrose wet mount demonstrating organisms in feces with light microscopy. Acid-fast staining. DNA of organisms in feces using PCR.

Differential Diagnosis!!navigator!!

  • Foal diarrhea associated with other organisms of the foal diarrhea complex
  • Transient lactose intolerance

CBC/Biochemistry/Urinalysis!!navigator!!

CBC unspecific or normal. Low serum albumin and total protein possible with severe cases.

Other Laboratory Tests!!navigator!!

N/A

Treatment ⬆ ⬇

TREATMENT

Supportive to correct dehydration, acid–base disorders and electrolyte imbalances, and energy demands. If animals are severely catabolic parenteral or oral nutritional support is indicated. No specific effective anti-protozoal treatment is currently available for horses.

Miscellaneous ⬆ ⬇

Outline

MISCELLANEOUS

Abbreviations!!navigator!!

PCR = polymerase chain reaction

Suggested Reading ⬆ ⬇

Burton AJ, Nydam DV, Dearen TK, et al. The prevalence of Cryptosporidium, and identification of the Cryptosporidium horse genotype in foals in New York State. Vet Parasitol 2010;174(1-2):139–144.

Slovis NM, Elam J, Estrada M, Leutenegger CM. Infectious agents associated with diarrhoea in neonatal foals in central Kentucky: a comprehensive molecular study. Equine Vet J 2014;46(3):311–316.

Author(s) ⬆

Author: Henry Stämpfli

Consulting Editors: Henry Stämpfli and Olimpo Oliver-Espinosa