Posted by Dr. Brian Dorcey on July 13 2009 11:33
What is it?
- Cryptosporidiosis (crypto), a disease affecting both animals and humans, is caused by the organism Cryptosporidium
- Not a bacteria or a virus... a protozoa
- Can affect mice, pigs, lambs, calves, dogs, cats, horses, and PEOPLE... so be careful!!!
How does it cause diarrhea?
- Invades the lining of the gut, kills the cells that absorb nutrients
- Diarrhea is caused by the lack of absorption of nutrients and subsequent loss of water into the gut leading to secondary milk fermentation. Dehydration causes severe illness and death.
Diagnosis
Organisms can be detected by a fecal sample pre-mortem, or intestinal scrapings post-mortem.
Transmission
- This disease is trasmitted by fecal-oral contamination
- Cryptosporidium can be transmitted directly in four ways: from animals to animals, form animals to humans, from humans to humans, or from humans to animals
- Livestock waste may be a source of water contamination, however, adult cows rarely, if ever, shed Cryptosporidium oocytes and are not a significant threat. This is a disease of young stock.
- Calves infected with C. parvum can shed up to 10 billion oocysts per day for 3 to 12 days
- Oocyst shedding also can occur without any clinical signs
- Heavy shedding results in a rapid increase in contamination of the calves' environment.
- Since infection is spread from calf to calf by oral ingestion of excreted oocysts, management practices to minimize contact with infected calves feces are important to help control of spread of disease.
Clinical Disease
- Calves 1-3 wk old are most suseptable
- Cryptosporidium can be the sole cause or can act in combination with other organisms such as rotavirus, coronavirus, and E. coli K99 to produce diarrhea.
- When acting in combination with other organisms, morbidity (illness) and mortality (death) rates increase
Clinical Disease
- Clinical Signs
- Anorexia, weight loss, diarrhea
- Feces may vary in consistency from loose to watery and may contain undigested milk, blood, mucus, and bile.
- Disease patterns are such that many calves often get sick, but few die
- Nutrient malabsorption and fluid loss results from damage to intestinal cells. Dehydration causes severe illness and death. Therefore, treatment is aimed primarily at maintaining hydration and nutrition in affected calves
Treatment
- Treatment is aimed primarily at maintaining hydration and nutrition in affected calves.
- Rehydration, correction of acidosis, and proper nutrition are key.
Prevention
- There is no disinfectant that can be practically used in a farm setting to inactivate Cryptosporidium.
- Minimize cross contamination between calves and environmental build-up of Cryptosporidium
Summary
- Cryptosporidium is common in dairy calves
- Young animals can be affected with Cryptosporidium parvum and shed the organism in large numbers when they have diarrhea.
- People can get Cryptosporidium by ingestion of oocysts (eggs). This is not uncommon in farm workers who care for sick animals.