Salmonella enteritidis isolated from an eared grebe (Podiceps nigricollis).

The reported prevalence of salmonellosis its wild birds is relatively low, though the numl)er of species of birds reported as having the disease or being carriers of the organism is increasilig (Faddoul et al., 1966, Avian Dis. 10: 8994). The course of the disease in binds ralsges from acute to chronic. Affected birds essay recover, become carriers of the organism alsd periodically shed it into the envinonnsent. This paper reports a case of chronic, fatal salmolsellosis in an eared grebe. A moribund eared gnebe was collected at the north end of Salton Sea National Wildlife Refuge, near Calipatnia, California, during an investigation of an avian cholera epizootic in February 1979. The carcass was frozels until examined at necropsy. Numerous caseous nodules (2= 10 mm in diameter) were found in the pectoral muscles, mvocandium, lungs, spleen, liver, and the serosal surfaces of the abdominal cavity, and the tlsonacic air sac. The walls of the cecum alsd colon were thickened and the lumen contained a caseonecnotic cone. Pectoral muscle atrophy and reduction of subcutaneous fat were also observed. Tissues were fixed in 10% formalin, embeddecl in paraffin, sectioned at 6 tm and staiised with harris hemotoxylin and eosin, the ZiehlNeelsen acid fast method, and Brown and Brenn’s method of the Gram-stain. Focal granulomas with macnophages containing small rodshaped gram negative bacteria were observed in the liver, lung, pectoral muscle, aIi(l Spleeli. Focal nonencapsulated caseonecrotic lesions containirsg dense aggregates of 1)acteria were present in both the m ocardium and tlse i ec toral muscles. A severe fibrilsohemorrhagic entenitis was also observed in tissue sections of the small intestine. Fibnin thrombi were present in many hepatic vessels. A gerseralized vacuolar clsange ‘as note(I in the hepatocvtes. Large