Molecular identification of Eimeria species infecting market-age meat chickens in commercial flocks in Ontario

A previously described multiplex PCR was evaluated for the identification and prevalence of Eimeria species in market-age commercial chicken flocks in Ontario. The multiplex PCR based on species-specific RAPD-SCAR markers was able to distinguish six available laboratory strains of Eimeria species (E. tenella, E. maxima, E. necatrix, E. mitis, E. acervulina, and E. brunetti) and E. tenella, E. maxima and E. acervulina in unknown field samples, including multiple infections in single reactions. No backyard (0/77) and 20/360 market-age commercial chickens were oocyst-positive using standard fecal flotation methods. PCR identified E. tenella alone (9/360, 2.5%), E. maxima alone (5/360, 1.38%), E. maxima plus E. tenella (5/360, 1.38%) and E. acervulina alone (1/360, 0.27%) in market-age commercial broilers. This is probably the first time the multiplex PCR has been evaluated in poultry establishments in Canada and illustrates the value of the tool in coccidiosis epidemiology on commercial farms.