Coccidiosis - Cattle

Eimeria sp. of ruminants - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona

Coccidia oocyst from ruminant faeces - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona

• Many species affect cattle

• Cattle under a year old are usually infected sporadically

• 2-3 week prepatent period

• Eimeria bovis
  • Endogenous stages in central lacteal of villi and epithelial cells of caecum and colon
  • Causes diarrhoea and enteritis
  • Oocysts are 28x20μm
  • Moderately pathogenic

• Eimeria zuernii
  • Endogenous stages in connective tissue of lamina propria of the lower small intestine and in the epithelial cells of the caecum and colon
  • More pathogenic than Eimeria bovis
  • Causes blood stained dysentery, tenesmus and sloughed mucosa
  • Oocysts are spherical and measure 16μm

• Mainly occurs in calves in poor conditions and bought-in calves
  • Also occurs in suckler calves turned out in spring

• Eimeria alabamensis associated with diarrhoea in calves after spring turnout

• Passive immunity is sufficient during the neonatal period

• Can be concurrent with cryptosporidium, viral and bacterial agents

Diagnosis

• History, clinical signs, diarrhoea (often with blood) and a decrease in weight gain

• Post-mortem
  • Diffuse inflammation and thickening of caecal mucosa (and sometimes ileal and colonic mucosa)
  • Masses of gamonts and oocysts in scrapings

• High faecal oocyst count
  • However, healthy animals can pass millions of oocysts from mixed species infections which have no pathogenic significance
  • Animals may die before oocysts are shed

Control

• Improve husbandry
  • Improve sanitation
  • Increase bedding
  • Raise food and water troughs to avoid faecal contamination

• Preventative in-feed medication
  • E.g. Decoquinate

• Injectable antiprotozoals may limit oocyst production but animals should still be moved to a clean environment
  • E.g. Sulphamethoxypyridazine