A comparison of two laboratory strains of Eimeria tenella

Abstract

Two strains of E. tenella (Weybridge and Houghton), which have been maintained by laboratory passage for at least 20 years without exposure to drugs, were compared.Oocyst dimensions and morphology were similar and cross-protection experiments showed that the strains could not be distinguished immunologically.One strain (Weybridge) caused greater caecal haemorrhage than the other when small doses of oocysts were given and was less completely controlled by some quinoline and pyridine drugs.Acknowledgements are due to Dr M. E. Rose of the Houghton Poultry Research Station who kindly made the Houghton strain of E. tenella available to us with details of its maintenance.The statistical calculations were made by Miss C. N. Hebert.