Objective To investigate the community structure, density, and seasonal variation of rodents at national-level surveillance sites in Chongqing, China, and to provide a basis for the prevention and control of rodent-borne diseases. Methods From January to November, 2018, the trap-at-night method and the route index method were used at four national-level surveillance sites in Chongqing. SPSS 25.0 software was used for statistical analysis, and the chi-square test was used for comparison of constituent ratio. Results In 2018, the density of rodents was 0.98% in urban surveillance sites and 0.73% in rural surveillance sites, with a mean density of 1.15% indoors and outdoors, and the highest density was observed in special industries (1.74%). The mean route index of rodents was 1.81/km in the external environment of various places, and the highest index was observed in waste transfer stations and public toilets (2.86/km). The dominant species was Mus musculus in both urban and rural areas, and there was a significant difference in the composition of rodent species between different habitats ( χ ²=32.814, P<0.001). Conclusion This study provides preliminary results of the rodents in Chongqing, and reasonable prevention and control measures should be adopted based on surveillance results in districts and counties.

Objective To investigate the distribution of mosquito populations in Chongqing, China, and to provide a basis for the development of mosquito control measures. Methods From August to October, 2018, eight districts/counties in Chongqing were selected according to their geographical locations for field investigation in both urban and rural areas. Mosquitoes were captured by trapping lamps, mosquito data were collected and descriptively analyzed by Excel 2010 and ArcGIS 10.60 softwares, and the rank sum test was used by SPSS 25.0 software for different mosquito species density in urban and rural areas. Results A total of 5 species of mosquitoes in 4 genera were collected, and the total mosquito density was 14.83 only/(lamp·hour). The urban mosquito density was 0.67 only/(lamp·hour), and the dominant species were Culex pipiens quinquefasciatus and Aedes albopictus; the rural mosquito density was 18.69 only/(lamp·hour), and the dominant species were Cx. tritaeniorhynchus and Armigeres subalbatus. Rongchang area had the highest total mosquito density, and the density of Cx. tritaeniorhynchus in rural areas was higher than that in urban areas (Z=-3.019, P=0.003). Conclusion The total mosquito density is relatively high in Chongqing, and appropriate mosquito control measures should be taken according to local conditions to prevent and control the occurrence of mosquito-borne diseases.

Objective To investigate the susceptibility of Blattella germanica to commonly used insecticides and optimize future application of insecticides. Methods The surface contact method was used, calculating the medium knock-down time(KT ₅₀) and obtaining resistance ratios by comparing with susceptible strain from 2015 to 2016. Results The resistance index of field-collected strains of B. germanica to beta-cypermethrin, deltamethrin, cypermethrin, acephate, DDVP, ehlorpyrifos, and propoxur were 13.76-32.93, 5.26-15.25, 4.81-21.02, 1.01-2.11, 1.05-7.38, 1.00-1.20, and 1.02-2.12. The average mortality of B. germanica in different areas of Chongqing after 72 h of contacting to acephate, ehlorpyrifos, DDVP, deltamethrin, cypermethrin, propoxur, and beta-cypermethrin were 100%, 100%, 94.0%, 92.0%, 81.0%, 79.0% and 78.0%. Conclusion Field collected strains of B. germanica in Chongqing have already developed different resistance to seven kinds of insecticides. Insecticides should be applied strategically to manage the insecticide resistance of B. germanica effectively.

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.

【Abstract】 Objective To learn the infestation situation of indoor cockroach in Chongqing, and control effectively its density to accumulate experience for its large scale control. Methods The residual spraying and toxic baits were used to kill cockroach, and the  control efficacy was evaluated by chemicals simulating method and visual method. Results The infestation rate reached 27.75% before treatment, and there was significant difference among the infestation situation of cockroach at six different places（χ2＝91.272, P＜0.01）.After treatment, it decreased to 6.46% and the killing rate was 76.72%. The control efficacy in the school was the best, and the killing rate reached 91.95%. The second was in the farm product trade market with the value of 86.19%. It was the worst in five small shops, and its killing rate to cockroach was only 60.79%. There was also significant difference among the control efficacy at six places（χ2＝55.235, P＜0.01）. Conclusion The control efficacy to cockroach was very distinct, which effectively reduced the density of cockroach. The results also showed many factors such as environment, work force and concern degree would affect the control effect. The environmental condition was better, the control of cockroaches was easier. The work force was bigger and the degree of concern was higher, the killing effect was more remarkable.