Enteritis (so-called runting stunting syndrome) in Georgia broiler chicks.

So-called runting stunting syndrome (RSS) afflicts chicks worldwide. The present study in Georgia chicks is the first report of unique histologic features of RSS pathology in chicks in the United States. Various combinations of avian nephritis virus, enterovirus-612, and reovirus were always isolated from chick small intestines. Ultrastructurally, only small round viruses were seen in small intestinal lesions. Although finding intralesional virus in small intestinal segments from chicks with signs and gross lesions consistent with RSS constitutes a reasonable criterion for making a diagnosis of this disease, chicks without intralesional viruses and with bacterial or protozoal enteritis may also be small and abnormally feathered. Because just what constitutes RSS remains a diagnostic dilemma, we recommend that the use of the imprecise acronym "RSS" be discontinued.