Sammendrag
Poultry coccidiosis caused by Eimeria spp is common globally, and the severity depend on host-associated factors and the species involved. Clinical signs include diarrhoea, poor growth, lethargy and dehydration and may cause high mortality in a flock. Coccidiosis is an important predisposing factor for the bacterial disease necrotic enteritis. Together, these intestinal diseases impair animal welfare and cause significant economic losses in the global poultry industry. The TEiCON project explores molecular tools for quantitative detection of Eimeria species in Norwegian broilers and investigate the distribution of species. Systematic sampling of droppings was performed at multiple time points in commercial flocks vaccinated with a live coccidiosis vaccine to study the dynamics of Eimeria spp. Samples of pooled fresh regular and ceacal intestinal droppings ensured representative sampling from each flock. Additional targeted samplings of case flocks diagnosed with coccidiosis, and matching control flocks, were performed. All samples were screened for selected Eimera species and Clostridium perfringens by real-time PCR. Eimeria oocysts (OPG) and C. perfringens were quantified by microscopy and bacterial counts, respectively, on fractions of the same samples. Eimeria tenella and E. acervulina were the most prevalent species identified in both case and control flocks, whereas E. maxima and E. mitis were rarely detected. These Eimeria species are all included in the vaccine the broilers received. None of the species could be associated exclusively with case flocks. Our results warrant more detailed investigations to verify if Eimeria strains present in case flocks are the same genetic variants originating from the vaccine.
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