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16. Treatment plan

Later in the week, Dr. Karl stops by the farm to see Chuck and to share the diagnostic laboratory results.
“Chuck, I am fairly confident that we are dealing with a Cryptosporidium problem on your farm, which is complicated by an occasional Salmonella infection,” Dr. Karl explains. Since both of these agents are zoonotic, Dr. Karl cautions Chuck to use personal protection (e.g. gloves) and good hygiene (e.g. hand washing) when working with the calves.

Dr. Karl continues, “The Salmonella strain isolated from your calves is multi-drug resistant. This means that one or more of our antibiotics will not be effective. The resistance of this bacterium may be due, in part, to the previous use of antibiotics. This secondary Salmonella infection was probably the cause of the first calf's death.”

“All right,” Chuck responds, “so what do we do to treat these calves and make them feel better?”

Regretfully, Dr. Karl replies, “The underlying cause of the scours in your calves is Cryptosporidia.  Unfortunately, no specific treatment will eliminate this protozoa.  Therefore, the only treatment is supportive therapy, including fluids and oral electrolyte solutions.  Furthermore, to control Cryptosporidium and prevent its spread to other calves, management changes are essential such as isolating sick calves, cleaning the environment, and using an all-in-all-out system for raising calves.

            Facts about Cryptosporidia and Cryptosporidiosis

*Caused by protozoan
*Can infect most domestic mammals

  • Outbreaks occur among veterinary caregivers

*Found commonly in calves less than 4 weeks of age
*Clinical signs in calves:

  • Diarrhea (loose to watery)
  • Blood in stool
  • Mucus in stool
  • Bile color in stool
  • Tenesmus

*High morbidity (>30%), low mortality (<5%)


  • Invade enterocytes in distal small intestines and large intestines
  • Live just under cell membrane
  • Destroy villi, which can lead to villi fusion
  • Oocyst excystion begins with the first signs of diarrhea, therefore infected animals should be isolated as soon as possible to hinder transmission and prevent shedding and contamination of the environment

*Typically disease of dairy and veal calves
*Typically causes infection in calves less than 4 weeks of age
*Can be subtyped by serotyping: Common serotypes of cattle include Typhimurium, Newport, and Dublin
*Clinical signs:

  • Depressed
  • Fever
  • Profuse diarrhea
  • Swollen joint(s)

*Low morbidity (<10%), high mortality (>50%)
*Commonly resistant to several antimicrobial agents

  • Colonize distal small intestine or colon
  • Fimbriae attach to enterocytes
  • Invade and destroy cells
  • Carrier state is possible



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