An outbreak of duck viral enteritis (duck plague) in domestic Muscovy ducks (Cairina moschata domesticus) in Illinois.

Duck viral enteritis (DVE) was diagnosed in an outbreak of the disease in a resident population of Muscovy ducks (Cairina moschata domesticus) on a privately owned multispecies game bird production facility in Illinois, where it claimed 625 ducks. This disease condition had not been reported previously in domestic ducks in Illinois. Although other varieties and age groups of domestic waterfowl (i.e., black ducks, rhumen ducks, Pekin ducks, ducklings, and geese) were present on the game bird farm, the morbidity and mortality (100%) in this epornitic was solely limited to adult ducks of the Muscovy lineage. The clinical signs in the affected ducks were lethargy, diarrhea, dehydration, and death within 2-3 hr of onset of symptoms. Gross pathologic changes were nonspecific and included ecchymotic hemorrhage, effusion of fluid and blood within body cavities reflective of an acute systemic infectious disease. Light microscopic findings were necrosis of primarily digestive lining epithelium and variable lymphohistiocytic infiltration within mucosal and serosal connective tissues. Intranuclear inclusions resembling characteristic herpetic (i.e., Cowdry type A) inclusions were observed primarily in the digestive, respiratory, and reproductive tracts; liver; and spleen. Esophageal candidiasis, bacteriosis, and systemic Pasteurella anatipestifer infections, thought to be concurrent or opportunistic infections, were present in several ducks. DVE virus was demonstrated in infected Muscovy duck embryo fibroblast cells by direct DVE virus-specific fluorescent antibody staining.