Diagnosis of Eimeria species using traditional and molecular methods in field studies.

The objective of this study was to identify and characterize species of Eimeria in broiler chickens using traditional morphological and pathological plus molecular (DNA amplification) diagnostic methodologies. Using a combination of those techniques it was possible to identify the presence of multiple circulating species in the flock as well as higher frequencies for some of them, especially Eimeria praecox and Eimeria maxima, which were identified in 100% of the flocks. The frequencies of the other species were Eimeria mitis and Eimeria necatrix (93.3%), Eimeria tenella (76,7%), Eimeria acervulina (56.7%) and Eimeria brunetti (16.7%). However using the lesion score, the most common species were E. maxima (46.7%), E. acervulina (30%), E. tenella (23.3%), and E. necatrix (10%). E. brunetti and E. praecox were not identified by using lesion score. DNA amplification had detection sensitivity for Eimeria species in the field samples of at least 20 oocysts. The implementation of DNA amplification as a routine diagnostic technique in aviaries can assist Eimeria population.