ISSN 1003-8280 CN 10-1522/R 中国疾病预防控制中心 主办
Objective To investigate the susceptibility of Aedes albopictus larvae to four insecticides in some areas of Chongqing. Methods To determine the median lethal concentration (LC50) of the field population of Ae. albopictus larvae of Yuzhong district and Wanzhou district located in the hinterland of the Three Gorges Reservoir, by immersing them with pesticide in 2014-2015. Results In comparison with the susceptible strain, the resistance ratios of Ae. albopictus larvae to beta-cypermethrin, deltamethrin, permethrin, and temephos were 7.59-, 4.50-, 9.88-, and 3.18-fold respectively in Yuzhong district, and 12.82-, 7.50-, 13.29-, and 2.00-fold respectively in Wanzhou. Conclusion Aedes albopictus larvae of Yuzhong had a low level resistance to beta-cypermethrin, deltamethrin, permethrin, and temephos; that of Wanzhou had a moderate resistance to beta-cypermethrin and permethrin, but a low level resistance to deltamethrin. Therefore, it is important to rotate pesticides and choose appropriate doses in mosquito control.
Objective To provide the basis for early detection and control of plague in the Three Gorges Reservoir through monitoring of the host animals, insects and plagues in this region. Methods Night traps were used to measure the rat density. Live rodents were captured using cage traps to collect serum samples for detection of plague F1 antibody and determination of parasitic fleas on the rodent body. Animals which died of unknown causes were recorded, and plague monitoring was carried out. Results The average rodent density was 1.49% in Chongqing area of the Three Gorges Reservoir from 2007 to 2008. The indoor density was 1.50%, the outdoor 1.48%. Rattus norvegicus, Mus musculus, R. tanezumi and Anourosorex squamipes were the dominant species. The average flea-carrying rate was 4.03%, and the total flea index was 0.13. The parasitic fleas found on those rats included Monopsyllus anisus (0.12%), Leptopsylla segnis (77.88%), Palaeopsylla remota (14.39%) and Xenopsylla cheopis (7.61%). For the 6549 surveyed live rats, the serological test was all negative for plague. There was neither a large number of dead animals of unexplained causes nor plague cases. Conclusion Plague was not found in Chongqing area of the Three Gorges Reservoir, though the vectors and host animals exist.
【Abstract】 Objective To investigate the breeding situation of mosquitoes in various plashes in urban areas of Chongqing and provide scientific evidence for mosquitoes control. Methods Direct observational method was used to investigate the breeding of mosquitoes in small?sized containers such as miniascape, crock, kettle and tyre, but direct observational method and scoop sampling method used in the large and medium?sized waters like water pool and lake. The proportion of breeding was recorded. Some larvae were collected and taken back to the laboratory to be classified. Results Mosquito larvae were found in all kinds of plashes except for fishing pond and lake. The average positive rate in small container was 10.65% (1.45%-91.11%), while it was 18.42% in the large and medium?sized waters. The dominant species were Aedes albopictus and Culex pipiens quinquefasciatus, accounting for 58.18% and 29.56% respectively. Conclusion The management of plashes mosquito should not be neglected in the mosquito control.