ISSN 1003-8280 CN 10-1522/R 中国疾病预防控制中心 主办
Objective To investigate the community structure of gamasid mites in a plague area of Dingbian county for further revelation of the role of these species in transmitting and preserving the plague bacillus. Methods The mites were collected from rodent bodies and nests, fixed in Hoyer’s medium and identified under the microscope. Results A total of 463 gamasid mites under 6 species, 5 genera and 3 families were collected. The dominant species included Haemogamasus kitanoi, Haemolaelaps glasgowi and Eulaelaps cricetuli, accounting for 40.6%, 33.0% and 24.8%, respectively, followed by a small amount of Macrocheles matrius, Macrocheles decoloratus and Laelaps algericus. Eight hundred fifty-nine rodents were captured and 135 nests were investigated. The dominant host mammal was Meriones unguiculatus, accounting for 90.9% of the total captives. The mite-carrying rate was 7.3% in M. unguiculatus and 23.7% of all nests. Most of the collected mites were female. Conclusion The community structure of gamasid mites is simple in this area with only a few species parasitic on the dominant host rodents. The dominant gamasid mites found on M. unguiculatus included H. kitanoi, H. glasgowi and E. cricetuli.
【Abstract】 Objective To study dividing line and influence factor of Aedes albopictus in Shaanxi province. Methods Adult mosquitoes were captured by mosquito?net trap, light trap and mosq?ovitrap method. Results Ae.albopictus distributed widely in Baoji and Hancheng city, and mainly at the special places such as worn type deposit places and junk recycle bin in Longxian and Tongchuan city. There was no Ae.albopictus in Yijun, Huangling and Yichuan. The peak of Ae.albopictus was in August in Baoji city and in September in Hancheng city. Temperature was possible the decisive factor that affected dividing line of Ae.albopictus. Conclusion The western boundary of Ae.albopictus was in Baoji city, the northern ones in Longxian, Tongchuan and Hancheng. Compared to light trap, mosquito?net trap and mosq?ovitrap method were best for the surveillance of Ae.albopictus, which would provide the ecological evidence for the control of mosquitoes.
【Abstract】 Objective To investigate the resistance of Culex tritaeniorhynchus to insecticides used frequently in high incidence areas of Japanese encephalitis in Shaanxi province. Methods The density of mosquitoes was calculated by labor hour method. Larva death rate of five insecticides and LC50 of eight insecticides were determined by distinguishing dosage method and median lethal dose method respectively. Results The average density of Cx.tritaeniorhynchus in breeding farm was 194.91/man· hour. The mortality of mosquitoes in Nanzheng, Hanyin, Hanbin and Pingli county was 1.84%-13.65% and 10.86%-31.25% after treatment by DDVP and deltamethrin for 24 h. Maximum LC50 of the same insecticide in different areas was1.27-8.00 times of the minimum. Conclusion Cx.tritaeniorhynchus developed different resistance to tested insecticides in four investigation sites, except that it was susceptible to cypermethrin in Hanbin, Nanzheng county and to DDT in Pingli, Nanzheng county. Cx.tritaeniorhynchus populations had developed high resistance to DDVP and deltamethrin, moderate resistance to permethrin. Rotational or mixed use of insecticides with different action mechanisms should be adopted to postpone the development of insecticide resistance.