Background: 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 São 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 enteritis, increased number of intraepithelial lymphocytes with bacteria adhered to the intestinal epithelium and lymphoid depletion in the spleen. E. tarda was isolated from several organs from all affected species. The phylogeny employing amplified fragment length polymorphism (AFLP) of eleven strains revealed high similarity (>90%) among the isolates regardless of the affected species or sampled organs. Ten isolates of E. tarda showed susceptibility to all tested antibiotics.

Conclusions: E. tarda was identified as the cause of death of the species examined. Further studies would be necessary to determine the virulence of these strains and the possible risks regarding public health.

背景： 爱德华氏菌感染是鱼类养殖业严重暴发的常见原因，除了代表可能的人畜共患病风险。但是，很少描述影响鱼类以外的其他物种的自然爆发。

目的：报告爆发由泰达肠杆菌（E. tarda）引起的急性死亡暴发，这种疾病影响到居住在巴西圣保罗州天然池塘的多种物种。

材料和方法：对3只成年罗非鱼，3只野鸭和1只雪鹭进行尸检，并进行进一步的微生物学测试。肉眼和显微镜下的病变都有记录。还确定了鱼和禽品系之间的抗生素敏感性和系统相似性。在E.氏菌物种是通过MALDI-TOF，局部确认SODB测序和系统进化分析。

结果：这三个物种之间的宏观发现包括肠扩张，粘膜充血和粘液至液体含量。常见的组织病理学发现包括急性肠炎，上皮内淋巴细胞增多，细菌附着在肠上皮细胞上以及脾脏淋巴样耗竭。从所有受影响物种的几个器官中分离到了塔德大肠杆菌。采用11个菌株的扩增片段长度多态性（AFLP）进行的系统发育研究表明，分离株之间的相似度很高（> 90％），而与受影响的物种或采样器官无关。十株大肠杆菌的分离株显示出对所有测试抗生素的敏感性。

结论： tar。E. tared被确定为该物种死亡的原因。有必要进行进一步的研究以确定这些菌株的毒力以及有关公共卫生的潜在风险。