Objective To analyze the surveillance results of small mammals and their body surface flea vectors in the Chongqing section of the Three Gorges Reservoir Region, China, ao as to provide basic data and scientific guidance for the prevention and control of rodent-borne diseases. Methods The surveillance data of small mammals and their body surface flea vectors in the Chongqing section of the Three Gorges Reservoir Region from 2019 to 2021 were collected to analyze the changes in the species composition, density, flea infestation rate, and flea index of small mammals. The Chi-squared test was performed for analysis of data using SPSS 25.0. Results A total of 2 860 small mammals of 10 species were found in the Chongqing section of the Three Gorges Reservoir Region, with a mean density of small mammals of 1.67%. In residential areas, the mean small mammal density was 2.74%; the density showed a decreasing trend over the years ( χ ²=22.493, P<0.001); and the dominant species were Rattus tanezumi, R. norvegicus, and Mus musculus. In cropland, the mean density of small mammals was 0.60%; the density of small mammals fluctuated at relatively low levels, with a statistical difference between the years ( χ ²=41.953, P<0.001); and the dominant species were R. tanezumi, Anourosorex squamipes, and Leopoldamys edwardsi. There was a statistical difference in the composition ratio of small mammals between residential areas and cropland areas ( χ ²=1 003.754, P<0.001). The flea infestation rate of the small mammals was 18.67%, and the total flea index was 0.70. The dominant flea species was Leptopsylla segnis. Serum antibody against plague was not detected. Conclusions The species and density of small mammals in the Chongqing section of the Three Gorges Reservoir Region during 2019 to 2021 have changed significantly as compared with the completion of the Three Gorges Reservoir. R. tanezumi is the dominant rodent species, and its indoor density is much higher than the national plague control standard limit. The flea species include L. segnis and Xenopsylla cheopis. Great attention should be paid to strengthening plague monitoring and timely rodent and flea control.

Objective To monitor five common pathogens carried by small mammals in key areas of Chongqing, China, so as to provide a scientific basis for the prevention and control of local rodent-borne diseases. Methods From 2021 to 2022, small mammals were collected using cage traps at night at three surveillance sites in the central urban area, Wanzhou District, and Fuling District of Chongqing. The liver, spleen, lung, and kidney tissues were collected to extract nucleic acids for detection of Leptospira interrogans, Rickettsia mooseri, and Bartonella by quantitative real-time PCR (qPCR) as well as Hantavirus and Dabie bandavirus by reverse transcription qPCR. Excel 2010 was used to sort and arrange the data. The SPSS 22.0 software performed statistical analysis on the experimental data. The species composition ratio and pathogen infection rate of rodents were compared by the Chi-squared test. Results A total of 1 188 small mammals were collected, among which Rattus norvegicus accounted for 33.50%, R. tanezumi accounted for 26.77%, Anourosorex squamipes accounted for 26.01%, and Mus musculus accounted for 9.85%, in addition to Leopoldamys edwardsi, R. nitidus, N. confucianus, Apodemus agrarius, and Crocidura attenuata, with a total of nine species. There was a significant difference in the species composition of small mammals between different surveillance sites ( χ ²=714.786, P<0.001). Four samples were positive for Seoul Hantavirus, 24 for L. interrogans, and 8 for Bartonella; the remaining samples were negative. A total of 33 small mammals were found positive, including 2 R. tanezumi and 1 R. norvegicus carrying both L. interrogns and Seoul Hantavirus. The overall infection rate was 2.78% for all pathogens, 0.34% for Hantavirus, 2.02% for L. interrogans, and 0.67% for Bartonella. There was a significant difference in the infection rates of the three pathogens ( χ ²=18.857, P<0.001). Conclusions L. interrogans, Bartonella, and Hantavirus were detected in small mammals in Chongqing. These pathogens were most frequently found in R. norvegicus, R tanezumi, and A. squamipes, which were mainly distributed in the key industries of urban Chongqing and the rural residential areas of Wanzhou District, and the authorities of these places should pay more attention to the spread and control of rodent-borne diseases.

Cockroaches are of common hygiene pest worldwide that seriously threatens human health. Because they like to hide in the dark environment, placing baits has become an important way to kill cockroaches indoors. However, the long-term use of conventional chemical insecticides is harmful to the human body and the indoor environment, and also leads to the development of insecticide resistance in cockroaches. Therefore, it is particularly important to develop safe and effective cockroach-killing baits. This article summarized the current advances in the research and application of cockroach-killing baits, in order to facilitate the exploration of new methods to prevent and control cockroaches in the future.

Objective To evaluate the effects of the Metarhizium anisopliae CQMa421 bait in controlling Blattella germanica in both laboratory and field settings, and to provide a reference for the application of fungal insecticides in the control of hygiene pests. Methods The M. anisopliae CQMa421 baits at different concentrations were prepared, and their effects on the population density of B. germanica were measured in the laboratory and field settings. SPSS 25.0 software was used to analyze mortality, median lethal time (LT ₅₀), median lethal concentration (LC ₅₀), and 90% lethal concentration (LC ₉₀) to evaluate the cockroach-killing effects of the M. anisopliae CQMa421 baits. The chi-square test was used to compare mortality between groups. Results The laboratory test showed that after feeding B. germanica for 12 days with the M. anisopliae CQMa421 bait at 1×10 ⁸ spores/g, LT ₅₀was (6.85±0.24) days. In the field test, after placing the M. anisopliae CQMa421 bait at 1×10 ⁸ spores/g (1 box/per 2.5 m ²) for 30 days, the relative density of B. germanica decreased by 93.22%. Conclusion The M. anisopliae CQMa421 bait at 1×10 ⁸ spores/g can effectively control the population density of B. germanica.

Objective To investigate the population distribution and density changes of mouse-like rodents in the Chongqing section of the Three Gorges Reservoir Area, China, and analyze the ecological influence of the Three Gorges Project on rodents, for an understanding of the potential spreading risk of rodent-borne diseases. Methods The surveillance data of mouse-like rodents in the Chongqing section of the Three Gorges Reservoir Area from 2005 to 2018 were collected for descriptive and linear regression analyses by Excel 2010 and SPSS 25.0 softwares, respectively. Results Thirteen species of mouse-like rodents were found in the Chongqing section of the Three Gorges Reservoir Area, with a total density of 1.68%. In residential areas, the density was 2.01%, and the dominant species were Rattus tanezumi,R. norvegicus, and Mus musculus. In cropland, the density was 1.37%, and the dominant species were Insectivora, R. tanezumi, and R. norvegicus. The density of mouse-like rodents in cropland showed a decreasing trend along the flow of the Yangtze river. The total density tended to increase with years, and reached its peak in March throughout the year. The density of R. tanezumi increased significantly with years, especially in residential areas. Conclusion The population distribution and density of mouse-like rodents have changed significantly after the completion of the Three Gorges Reservoir, and there is a risk of occurrence and spread of rodent-borne diseases. Surveillance and control of mouse-like rodents should be strengthened.

Objective To investigate the results of emergency surveillance of Aedes vector before mosquito control after the occurrence of the index case of dengue fever in the epidemic areas of Chongqing, China, and to provide a basis for future surveillance of Aedes vector and early warning research on the risk of local transmission of dengue fever. Methods The surveillance data of Aedes vector were collected after the first cases of dengue fever were reported and before the mosquito control measures were adopted in each epidemic area of Chongqing, including Breteau index (BI) and double mosquito net index (DMNI), and SPSS 25.0 software was used for data description and linear regression analysis. Results The average BI for the first-time emergency surveillance in all epidemic areas was 11.01, and the average was 5.10 mosquitoes/net·hour, with a positive correlation between the two indices ( r=0.517, P<0.05). The bivariate linear regression analysis was used to establish the regression equation of BI and DMNI: y (BI)=7.07+0.82 x ( F=61.232, P<0.005), and the early warning of dengue fever risk in Chongqing was stratified into four levels based on this equation. Conclusion Graded assessment of BI and DMNI acts as an indicator for the early warning of dengue fever risk. For Chongqing, BI controlled below 7 and DMNI controlled below 3 mosquitoes/net·hour may reduce the risk of local outbreak of dengue fever.

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 populations and carried pathogens of plague-related host animals and vector fleas in Yunyang county of the Three Gorges Reservoir Area, and to understand the potential risk of plague occurrence in this region. Methods In April 2018, an investigation was conducted in the cultivated land and residential areas of Yunyang county, Chongqing. Rodents were captured by cage trapping method. Rodents and parasitic fleas collected by comb inspection were identified. Rodent blood was collected for serological testing. Results A total of 8 species of rodents were captured, the total rodent density was 2.52%, capture rate. The indoor and outdoor dominant species were Rattus tanezumi and Apodemus agrarius, respectively. The flea-carrying rate was 50.46% and the total flea index was 4.24, with the dominant flea species Leptopsylla segnis. The free flea index was 0.001. The plague serum antibody was not detected. Conclusion There might be a risk of local epizootic risk with imported plague in Yunyang county of the Three Gorges Reservoir Area, since there exists plague host animal and vector fleas. It implies the need for epizootic plague surveillance program in the county.

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.