Pathogenesis of Eimeria praecox in chickens: virulence of field strains compared with laboratory strains of E. praecox and Eimeria acervulina
The pathogenesis in chickens of the apicomplexan Eimeria praecox was compared with that of Eimeria acervulina, using intestinal lesions, mucosal integrity, body weight gain (BWG) and the feed conversion ratio (FCR) as criteria. Characteristics of each species were described by combinations
of polymerase chain reaction assays and classic parasitological signs. There were considerable overlaps in lengths, breadths, shape indices and volumes of the oocysts of each species. Both species caused statistically significant reductions in BWG at the lowest inocula tested (500,000 sporulated
oocysts per bird of E. praecox and 250,000 of E. acervulina). E. praecox was observed for the first time to cause actual body weight loss and marked increases in FCR, as did E. acervulina. E. acervulina caused gross, white pathognomonic lesions, but E. praecox caused micro-lesions, visible
in fresh tissue only with a dissecting microscope. Occasionally, lesions of the Houghton strain of E. acervulina were observed to be rounded, rather than typically “ladder-like”. Both species caused villous erosion and atrophy. No mortality occurred in birds receiving up to 1 million
sporulated oocysts of either species. Using BWG and FCR as criteria, the virulence of recent field strains of E. praecox from Wales (Tynygongl) and the USA (Raleigh) was compared with English laboratory strains of E. praecox (Houghton) and E. acervulina (Houghton). E. praecox (Tynygongl) was
markedly more virulent than E. acervulina (Houghton), which was more virulent than E. praecox (Raleigh) and E. praecox (Houghton).
Document Type: Research Article
Affiliations: 1: Coxitec Consulting, Hertfordshire, UK 2: Veterinary Laboratories Agency (Weybridge), New Haw, Addlestone, Surrey, UK 3: Laboratorios Hipra, Amer, Girona, Spain 4: Department of Animal Pathology, Faculty of Veterinary Sciences, University of Zaragoza, Spain
Publication date: 01 October 2009
- Editorial Board
- Information for Authors
- Subscribe to this Title
- Ingenta Connect is not responsible for the content or availability of external websites
- Access Key
- Free content
- Partial Free content
- New content
- Open access content
- Partial Open access content
- Subscribed content
- Partial Subscribed content
- Free trial content