Investigating a persistent coccidiosis problem on a commercial broiler-breeder farm utilising PCR-coupled capillary electrophoresis

In the present study, we utilised a polymerase-chain-reaction-coupled capillary electrophoresis (CE) approach to investigate the epidemiology of Eimeria species on a broiler-breeder farm in Victoria, Australia. The Eimeria populations of two flocks vaccinated against coccidiosis were followed over an 11-week period. All seven recognised Eimeria species of chickens were detected in both flocks. One flock suffered increased morbidity and mortality in its eighth week and had consistently higher Eimeria oocyst counts, species prevalences and rates of co-infections. Four Eimeria species included in the vaccine administered occurred at higher prevalences before the disease outbreak in the flock. Using the CE approach, two new, previously undescribed Eimeria genotypes were discovered in both chicken flocks, one of which dominated toward the end of the study period. The molecular approach proved versatile and capable of providing useful epidemiological data which could be used to investigate and interpret coccidiosis outbreaks.