Surveillance results and dynamic patterns of rats in Alataw Pass areas in Xinjiang in 2008.

Objective To determine the current situation and dynamics of rats around Alataw pass areas,providing evidence for early warning,prediction,prevention and control. Methods Fifteen monitoring sites,including different habitats such as downtown,outskirts and natural fields around the Pass,were established using cages,traps and cave detectors. Exoparasites were classified and identified. Blood and organ samples were collected from captured rats for micro determination of F1 antibodies and antigens. Positive results were retested using test tubes. Results A total of 599 small mammals of 13 species belonging to 10 genera,6 families and 4 orders were captured around the Alataw pass in 2008,the annual average capture rate being 2.8% (0.5% in urban areas,2.1% in suburban areas and 4.6% in fields). The dominant species was Mus musculus in urban areas,Rhombomys opimus in outskirts and fields. A total of 6050 fleas of 17 species from 12 genera and 6 families were collected,dominated by Xenopsylla minax. 238 ticks and 23 mites were also collected. Serological assays revealed 873 positive samples of F1 antibody and 548 of F1 antigens. Four batches of rodents,one of canine bodies and three of mites were found in the aboard-passing vehicles,amounting to 338. Conclusion The rat density had reduced to the lowest level around the urban areas of Alataw pass in 2008. R. opimus were the dominant species in the suburbs and fields,mostly mediated by X. minax,indicating that epidemics among R. opimus were still present. A variety of vectors were found entrained in the aboard-passing vehicles,increasing the risk of epidemic transmission.