Mortality in Captive Rhesus Monkeys ( Macaca mulatta ) in China Due to Infection with Yersinia pseudotuberculosis Serotype O:1a

The most common serotypes of Yersinia pseudotuberculosis infecting non-human primates are serotypes O:1b, O:3, O:4, and O:7. The O:1a serotype has never been reported in non-human primates. The present study describes an outbreak of serotype O:1a with high fatality (6/18) in captive rhesus monkeys in China. Bacteria were isolated from different organs of the carcasses using standard microbiological procedures. The strain was identified using conventional and molecular techniques such as morphological and biochemical identification, serotype determination, PCR-sequence analysis based on the 16S rRNA gene, detection of virulence genes, and antimicrobial susceptibility testing. The pathogenicity was determined after experimental infection in mice. Taken together, the obtained data indicate that Y. pseudotuberculosis O:1a is a pathogen of concern and represents a potential threat to monkey conservation efforts.