Edwardsiella tarda outbreak affecting fishes and aquatic birds in Brazil

AbstractBackground: Edwardsiella tarda infections are frequent causes of severe outbreaks in the fish farming industry besides representing possible zoonotic risks. However, naturally occurring outbreaks that affect various species besides fishes are seldom described.Aim: To report an outbreak of acute mortality caused by E. tarda affecting multiple species that inhabited a natural pond in the state of Sao Paulo, Brazil.Materials and methods: Three adult tilapias, three Mallard ducks and one Snow egret were necropsied and subjected to further microbiological tests. Gross and microscopic lesions were documented. The antibiotic susceptibility and phylogenetic similarities among fish and avian strains were also determined. The E. tarda species was confirmed through MALDI-TOF, partial sodB sequencing and phylogenetic analysis.Results: Macroscopical findings between the three species included intestinal dilatation, mucosal hyperaemia and mucous to liquid contents. Common histopathology findings included acute ...