Surveillance on Major Species of Host Animals and Vectors of Plague in Shenzhen City

Objective To understand the situation of animal plague epidemic in the Shenzhen city. Methods Host animals were caught by cage. Flea was classified after being identified. Yersinia pestis F1 antibodies were detected by IHA and Yersinia pestis was separated by organ impression. Results 472 rat-like animals were captured from 25 surveillance sites in 4 districts, belonging to 2 orders, 3 genera, and 4 species. The capture rate was 8.25%. R.norvegicus, the dominant species in this surveillance, constituted 87.32% of the total number. R.flavipectus, S.murinus and B.indica accounted for 8.03%, 4.42% and 0.21% of the total number, respectively. Gender ratio was 1∶0.82, (famale:male). Reproduction index of R.flavipectus was 0.55, the highest among all, followed by R.norvegicus (0.41), and S.murinus (0.14), hinting that the population size of R.flavipectus might grow more rapidly than the other species in the future. Out of 472 rat-like animals, 129 were identified to be parasitized by 565 flea, all of which were Xenopslla cheopis. Total flea infection rate was 27.33% and the flea index was 1.20. R.flavipectus had the highest flea infected rate (63.16) and flea index (3.80). Flea infecting rate and flea index for R.norvegicus and S.murinus were 25.70%, 15.00%, 1.01 and 0.20, respectively. Capture rate in 5 different habitats varied from 2.61% to 5.42% and flea index of X.cheopis ranged from 0.68 to 2.59. 10 out of 25 surveillance sites X.cheopis flea index was 10. No F1 antibody was detected by IHA from 458 samples. No Yersinia pestis was culuted from 407 organs. Pathogenological and serological results were all negative. Conclusion Currently, no animal plague epidemic was found in Shenzhen city, but relatively high density of host animals and vectors were found, which would possibly facilitate animal plague epidemic if no proper measures was implemented.