Pathological aspects of a septicemic salmonellosis outbreak caused by Salmonella serotype Typhimurium in captive blue-fronted Amazon parrots (Amazona aestiva)

Abstract

There are reports of septicemic salmonellosis in exotic birds caused by Salmonella enterica serotype Typhimurium, although they are scarce and do not address the anatomopathological and immunohistochemical aspects of this condition in blue-fronted Amazon parrots (Amazona aestiva). This study aims to report an outbreak of salmonellosis by S. Typhimurium in 15 blue-fronted parrots introduced to a rehabilitation center in the state of Mato Grosso do Sul, Brazil. Hepatomegaly and splenomegaly, accompanied by flat white areas in the capsule and parenchyma, were the most frequent gross changes, histologically represented by necrotic and heterophilic hepatitis and splenitis and associated with bacteria in the cytoplasm of macrophages and free in the affected tissue. S. Typhimurium was identified from bacterial culture, PCR, and DNA sequencing. Along with immunohistochemistry samples of liver, spleen, kidney, small intestine, pancreas, thyroid, heart, and lung, immunostaining was used for Salmonella spp. without previous bacterial isolation. The lethality of this outbreak demonstrates the relevance of salmonellosis in blue-fronted parrots, which are known to be carriers of this bacteria.