Research Note: Hypervirulent arthritis-causing Salmonella Pullorum isolated from Chinese native chicken breeds significantly decreased growth performance of chicks

Pullorum disease is characterized by white diarrhea resulting from infection by S. Pullorum, but arthritis associated with S. Pullorum infection has become increasingly frequent recently, especially in Chinese native chicken flocks. In this study, we isolated and identified 4 S. Pullorum strains from the Qingjiaoma chicken breeders with arthritis symptoms. The LD50 of the isolate 20JS04 was 1.33 × 106 CFU, which was considered as a highly virulent strain in chicks. Reproducible arthritis symptoms were observed in the experimentally chickens infected with the isolate 20JS04, and the disease occurrence was 27.78% (5/18). In addition to the characteristics of high virulence and induced-arthritis, our results confirmed that the arthritis-causing isolate 20JS04 had greater negative impact on BW, ADFI, and ADG, compared with the white diarrhea-causing S. Pullorum standard strain CVCC526 (P < 0.05). These results suggest that the pathogenic diversity of S. Pullorum in China deserves more attention and stringent measures should be taken to control salmonellosis.