From Cow
Eimeria spp, the primary culprit in scours in calves
Classic soiled perineum and tail in a calf with coccidiosis

Coccidiosis is a parasitic disease which causes scours (diarrhoea) in young cattle. This disease is considered to be of considerable importance for the productivity and health of cattle worldwide[1].

It is frequently caused by Eimeria zuernii, E. bovis and E. auburnesis.

Coccidiosis is primarily a winter disease of young cattle under 1 year old, although older cattle and feedlot cattle are susceptible year round. Purebred cattle appear more prone than Zebu crossbred breeds[2].

Clinical signs

Many cases may present subclinically as intermittent diarrhoea. Acutely affected calves often show tenesmus when defecating and some may be febrile.

Severe infections are rare, and usually have bloody diarrhea that may continue for more than 1 week Dehydration is a common complication in acute cases. Calves that survive severe illness can remain permanently stunted. Calves with concurrent enteric infections (eg, Giardia spp) may be more severely affected.

Nervous signs (eg, muscular tremors, hyperesthesia, clonic-tonic convulsions with ventroflexion of the head and neck, nystagmus) and a high mortality rate (80–90%) are seen in some calves with acute clinical coccidiosis.


Diagnosis in most cases can be made by fecal analysis and identification of oocysts on fecal flotation or direct smear[3]. PCR testing on fecal samples is an additional, highly accurate test, but presence of some protozoa do not necessarily infer incrimination as causative agents[4].

Differential diagnoses include Salmonellosis, bovine viral diarrhea, malnutrition, toxins, or other intestinal parasites.


Treatment is usually symptomatic with fluid and electrolyte therapy, both oral or intravenous as required.

Antimicrobial coverage is indicated in severe cases, and includes sulfaquinoxaline, toltrazuril 5% oral suspension)[5] or amprolium. Toltrazuril appears most effective in long-term studies of its use in calves, promoting greater weight gains compared to other coccidiostats[6].

The value of frequent emptying and cleaning of water troughs in reducing the exposure of calves to Eimeria spp and thus lowering the impact of coccidiosis, both clinical and subclinical should be communicated to cattle farmers[7]. Feeding practices adopted that avoid fecal contamination of feed, calves grouped by size, and an “all-in/all-out” method of calf movement from pen to pen adopted.


  1. Koutny H et al (2012) Bovine Eimeria species in Austria. Parasitol Res 110(5):1893-1901
  2. Almeida Vdos A et al (2011) Frequency of species of the genus Eimeria in naturally infected cattle in Southern Bahia, Northeast Brazil. Rev Bras Parasitol Vet 20(1):78-81
  3. Bangoura B et al (2012) Prevalence of Eimeria bovis and Eimeria zuernii in German cattle herds and factors influencing oocyst excretion. Parasitol Res 110(2):875-881
  4. Lalonde LF & Gajadhar AA (2011) Detection and differentiation of coccidian oocysts by real-time PCR and melting curve analysis. J Parasitol 97(4):725-730
  5. Jonsson NN et al (2011) Efficacy of toltrazuril 5 % suspension against Eimeria bovis and Eimeria zuernii in calves and observations on the associated immunopathology. Parasitol Res 109(1):S113-28
  6. Veronesi F et al (2011) Long-term effect of toltrazuril on growth performances of dairy heifers and beef calves exposed to natural Eimeria zuernii and Eimeria bovis infections. Vet J 190(2):296-299
  7. Mitchell ES et al (2012) Husbandry risk factors associated with subclinical coccidiosis in young cattle. Vet J 193(1):119-123