Surveillance for plague in Jinghong, Yunnan,2003-2012

Objective To understand the status quo of plague epidemic in animals in Jinghong, Yunnan province and provide scientific evidence for plague prevention and control. Methods From 2003 to 2012,one fixed surveillance site for monthly surveillance and 1-2 floating surveillance sites for plague host or vector surveillance were set every year. Rodents were captured by using cages to detect flea on rodents. Ground free flea were picked up by using flea sticking paper. Hemagglutination test(IHA)was conducted to detect plague F1 antibodies in rat sera. Yersinia pestis was isolated from rat organs and flea specimens respectively. Results A total of 5657 rats in 5 species were captured during 2003-2012. The rat density ranged from 2.30% to 6.57%. The overall rat density was 4.01%. Rattus flavipectus accounted for 99.82% of the total rats captured(5647/5657). Fleas were detected in 753 rats(13.31%, ranging from 4.06% to 25.34%). A total of 1784 fleas were detected in rats and flea index in rats ranged from 0.11 to 0.80. The overall flea index in rats was 0.32. Xenopsylla cheopis accounted for 52.35%(934)and the index of Xenopsylla cheopis in Rattus flavipectus was 0.17(934/5647). A total of 45 473 flea sticking paper were placed and 7526 fleas were picked up. The ground free flea index was 0.17. The ground free Xenopsylla cheopis index ranged from 0 to 0.034. Six strains of Yersinia pestis were isolated from the organs of 5657 rats(0.11%).In IHA, 16 of 2896 serum samples were positive(0.55%). In reverse IHA, 4 of 108 serum samples were positive(3.7%). No Yersinia pestis was detected in fleas. Conclusion Plague in amimsls occasionally occurs in Jinghong. It is necessary to strengthen the surveillance, conduct regular mass deratization and depulization as well as health education to control animal plague and prevent the spread to human.