Eimeria species in commercial broiler complexes in the United States

Identifying Eimeria parasites has historically been done through biological characteristicssuch as pre-patent period, morphology and site of infection. All of these methods are timeconsuming and when parasites are in low numbers, species can easily be overlooked. PCRtechnology has provided a tool for rapid and accurate idenification. Eimeria species incommercial broiler facilities in the United States were identified using PCR. Results showed sixspecies (E. acervulina, E. brunetti, E. maxima, E. mitis, E praecox and E. tenella) frequently inthe forty-three complexes tested. Drug sensitivity of these Eimeria field isolates were testedusing Anticoccidial Sensitivity Tests. Infections of isolates of E. maxima were also investigated. The reproductive indexes, patent period and pathogenicity of field isolates from the United States and from commercial vaccines. The identification methods described are important in accurately characterizing Eimeria and necessary in determining the best anticoccidial program.