A retrospective analysis of cystic enteropathy in Alabama broilers.

Runting-stunting syndrome (RSS) is an enteric disease of young chickens with complex aetiopathogenesis. It is often linked to the isolation of multiple virus species and histologically characterized by cystic enteropathy. We investigated the correlation between the detection frequency of avian reovirus, astrovirus, parvovirus, and rotavirus A and the presence of microscopic lesions consistent with cystic enteropathy in 123 broiler chicken submissions to the Alabama State Laboratory System (Auburn, AL, USA). Multi-viral detections were found to be predictive of cystic enteropathy with an increased odds of 4.6 for every additional virus species detection. These results suggest a cumulative effect of enteric viruses on the likelihood of cystic enteropathy. Avian reovirus was frequently associated with cystic enteropathy (59.0% of cases). Next-generation sequencing detected the presence of more than one reovirus strain in seven of the eight tested isolates. Classification into multiple genotypes suggested that genetically diverse avian reoviruses may cause similar clinical signs.