Cryptosporidium in Calves (C. parvum)

What is Cryptosporidium parvum?

Cryptosporidia are single-celled parasites and are highly infectious. The oocysts represent the inactive, infectious, persistent form of the parasite. They are excreted in the feces of infected animals and are highly resistant in the external environment. In the intestine, cryptosporidia multiply in the intestinal epithelial cells of the brush border. In adult animals, cryptosporidia cause subclinical infections that resolve completely.

Symptoms of Cryptosporidium in Calves

In calves, severe infection of enterocytes by Cryptosporidium can lead to absorption disorders and, consequently, to malabsorption syndrome with weight loss. Calves under 4 weeks of age are particularly affected. Fatalities occur only rarely. However, Cryptosporidium, often as co-infections with rotaviruses, coronaviruses, and E. coli K99, is responsible for calf diarrhea in the first weeks of life.

Cryptosporidium parvum adheres apically to the enterocytes of the distal small intestine and the large intestine without penetrating the cell. This leads to a loss of microvilli, villous atrophy and fusion—resulting in a reduced absorption surface area—as well as inflammatory changes. The pathogen exhibits low host specificity.

Transmission and Hygiene on the Farm

The environmentally resistant oocysts are excreted in feces and transmitted via the fecal-oral route. Cryptosporidium parvum is one of the most common causes of diarrhea in calves and frequently occurs in combination with rotaviruses, coronaviruses, and E. coli K99. The pathogen has zoonotic potential: C. parvum can cause disease in humans, which must be taken into account in immunocompromised individuals and in farm hygiene practices.

Diagnosis of Cryptosporidium

Cryptosporidium-induced diarrhea alone is often mild and self-limiting; however, when combined with other pathogens, it can be persistent and lead to weight loss. Since a clinical etiological diagnosis is not possible, the detection of antigen in feces is used to classify the condition within the spectrum of diarrhea.

The Fassisi® BoDia test family (BoDia, BoDia Plus, Fassisi BoDia + Gia, Fassisi BoDia MPX, Fassisi BoDia Advanced MPX) detects Cryptosporidium parvum (cryptosporidia) in calf feces, along with other diarrhea-causing pathogens.

Sources for the information provided.