Mass mortality of Eurasian Tree Sparrows (Passer montanus) from Salmonella Typhimurium dt40 in Japan, winter 2008-09.

Abstract An outbreak of salmonellosis in wild passerines caused mass mortality of Eurasian Tree Sparrows (Passer montanus) in Hokkaido, Japan, 2005–06; however, the etiology was poorly understood. In winter 2008–09, sparrow mortality again occurred in Hokkaido, and 202 deaths in 100 incidents at 94 sites were reported. We conducted a comprehensive investigation to evaluate the cause and impact on sparrow populations. We collected 26 carcasses at 13 sites, including a zoological park. In addition, Salmonella screening of zoo animals was conducted as a biosecurity measure. Salmonella Typhimurium was isolated from multiple organs in all examined sparrows; they were diagnosed with septicemic salmonellosis. Eleven sites (85%) were related to wild bird feeding and six of eight sparrow fecal samples, including from the zoo, were S. Typhimurium-positive. No infection was detected in zoo animals. Isolates belonged to three phage types: DT40 (88%), DT110 (8%), and DT120 (4%). Pulsed-field gel electrophoresis patter...