Objective To investigate common pathogen infections in small mammals in Ningbo, Zhejiang Province, China, so as to provide a basis for the prevention and control of rodent-borne diseases. Methods From 2020 to 2022, small mammals were captured using the night cage-trapping method in Zhenhai District, Ninghai County, Cixi and Yuyao cities of Ningbo. The small mammals were identified by morphological method, and their livers, spleens, lungs, and kidneys samples were collected. Real-time fluorescent quantitative PCR (qPCR) or reverse transcription-qPCR (RT-qPCR) was used to detect four pathogens: Hantavirus, Dabie bandavirus (i.e., Severe fever with thrombocytopenia syndrome virus), Leptospira, and Orientia tsutsugamushi. The differences in pathogen positive rates in the small mammals between different species, sexes, habitats, districts (counties, cities), and years were compared using the χ ² test or Fisher’s exact test. Results A total of 668 small mammals were captured, of which Rattus norvegicus (24.70%) and Niviventer confucianus (23.65%) were dominant species. The overall positive rate of the four pathogens in the small mammals was 9.43%, of which Hantavirus (all Seoul virus) and Leptospira accounted for 2.84% and 6.89%, respectively. Coinfections with two viruses were found, with a coinfection rate of 0.30%. Neither Dabie bandavirus nor O. tsutsugamushi was detected. There were significant differences in the overall positive rate of pathogens in the small mammals between different species and between different habitats (all P<0.001), but not between different sexes, different years, and different districts (counties, cities) (all P>0.05). Among various small mammal species, the positive rate of Hantavirus was the highest in Mus musculus and in R. norvegicus (10.00% and 8.48%, respectively); the positive rate of Leptospira was the highest in R. losea (15.38%). In different habitats, the positive rate of Hantavirus in small mammals was the highest in key industries (10.84%); the positive rate of Leptospira was the highest in urban residential areas (11.76%). In different districts (counties, cities), the positive rate of Hantavirus in small mammals was the highest in Cixi (9.90%). The positive rates of Leptospira in small mammals in Yuyao and Ninghai were higher, at 10.00% and 9.12%, respectively. Conclusions Infections with pathogens such as Hantavirus and Leptospira in small mammals are found in Ningbo, which pose a potential threat to the health of the local population. Targeted prevention and control measures should be taken to reduce the risk of human infections.

Objective To investigate overwintering Aedes albopictus eggs and the dengue virus carried by the eggs in the former dengue epidemic focus in Ningbo, Zhejiang province, China, and to provide scientific evidence for dengue control. Methods During December 2018 to March 2019, standing water and sludge in containers were collected from the former dengue epidemic focus (including the core area, warning area, and monitoring area) of Haishu district and three non-epidemic areas (Beilun district, Cixi city, and Ninghai county) in Ningbo, for incubation of Ae. albopictus eggs under laboratory conditions. Real-time RT-PCR was used to detect the dengue virus carried by the eggs. The chi-square test and logistic regression analysis were used to determine the influencing factors of the positive rate of overwintering Ae. albopictus eggs. Results A total of 884 samples were collected, and the positive rate of overwintering Ae. albopictus eggs was 11.99%. There were significant differences in the positive rate of overwintering Ae. albopictus eggs between different dengue control areas ( χ ²=31.227, P<0.001) and between different water containers ( χ ²=38.044, P<0.001). According to multivariate analysis, the positive rates for the warning area, monitoring area, and non-epidemic area were 5.33 (95% confidence interval[ CI]:1.16-24.49), 6.26 (95% CI:1.37-28.65), and 11.56 (95% CI:2.75-48.50) times that for the core area, respectively. The positive rates for waste tires and vegetative containers were 3.59 (95% CI:1.79-7.20) and 3.77 (95% CI:1.82-7.79) times that for stationary containers, respectively. All test results for the nucleic acid of dengue virus were negative. Conclusion The warning area and monitoring area of the former dengue epidemic focus, non-epidemic areas, waste tires, and vegetative containers are the main breeding sites for overwintering Ae. albopictus eggs. It is suggested that relevant departments should take timely measures focusing on the removal of standing water to control mosquitoes in early spring.

Objective To investigate the population and density of flies in Ningbo, Zhejiang province, China, the resistance levels of Musca domestica to commonly used insecticides, and to provide a scientific basis for fly prevention and control. Methods The cage trapping method was used to investigate the fly population and density from April to November, 2019, and the topical application method was used to measure the resistance of the wild population of M. domestica in Ningbo to five commonly used insecticides. SPSS 22.0 software was used to perform the probit regression analysis. The median lethal dose (LD ₅₀) was calculated, and the wild population and sensitive population were compared in terms of LD ₅₀ to calculate resistance ratio. Results The total fly density in Ningbo, 2019 was 2.39 flies/cage, and M. domestica accounted for 36.00% of the total catch. Among various counties(cities, districts), Beilun district had the highest total fly density (4.73 flies/cage), and Zhenhai district had the lowest (0.42 flies/cage). Among various habitats, farmers' market had the highest fly density (3.05 flies/cage), and the lowest was found outside restaurants (1.97 flies/cage). The total fly density peaked in August. The resistance ratio of M. domestica in Ningbo to propoxur was >269.52 times, and those to deltamethrin, DDVP, beta-cypermethrin, and permethrin were 240.78, 46.89, 34.83, and 28.56 times, respectively. Conclusion As the dominant fly species in Ningbo, M. domestica has developed relatively high resistance to propoxur, deltamethrin, DDVP, beta-cypermethrin, and permethrin. It is suggested that scientific management and technical guidance for the wise use of insecticides should be strengthened in future to delay the development of resistance.

Objective To investigate the density fluctuation of the dengue vector Aedes albopictus and its resistance to commonly used insecticides in four regions of Zhejiang province, China, and to provide a basis for rational selection and use of insecticides and scientific prevention and control of dengue. Methods The density of adult Ae. albopictus was monitored by the double mosquito net method in four cities of Hangzhou, Ningbo, Quzhou, and Yiwu in Zhejiang province from April to November of 2018. The larvae were collected and reared to adults for determining resistance using the diagnostic doses of insecticides. Results The annual average net trap index was 1.33 mosquitoes/net·hour in the four prefectures of Zhejiang province, and that was 1.60 mosquitoes/net·hour in residential areas, which was the highest among three habitats. The Ae. albopictus population of Hangzhou was sensitive to three pyrethroids and malathion, and showed suspected resistance to propoxur. The mosquito population of Ningbo showed sensitive to beta-cypermethrin, suspected resistance to deltamethrin, permethrin, and propoxur, and resistance to malathion. The Ae. albopictus populations of Quzhou and Yiwu were sensitive to malathion, and exhibited suspected resistance to three pyrethroids and propoxur. Of the mosquito populations of the four cities, 5.00%, 60.00%, and 35.00% showed resistance, suspected resistance, and sensitivity to five insecticides, respectively. Conclusion In the four cities of Zhejiang province, the density of Ae. albopictus in residential areas and parks peaks in July. The mosquitoes develop varying degrees of resistance to the tested insecticides. Strengthening the surveillance of their density fluctuation and insecticide resistance contributes to slowing the development of resistance and effectively controlling dengue.

Objective To analyze the Aedes surveillance data of dengue fever outbreak in urban Ningbo, Zhejiang province, China, and compare the effects of three vector control measure packages on the density of adult Aedes mosquitoes and Breteau index (BI), and to provide a basis for formulating emergency management of dengue in the locality. Methods Three different comprehensive measure packages were used to control mosquitoes:measure package 1 included ultra-low-volume spraying, thermal fogging, slow-release agent, and environmental management; measure package 2 included ultra-low- volume spraying, residual spraying, slow-release agent, and environmental management; measure package 3 combined the 5 methods mentioned in measure package 1 and 2. The decline rate with net trap index and control effect with BI were compared between the 3 measure packages using ANOVA or rank sum test and curve fitting, respectively. Results There were no significant differences in the decline rate with net trap index between the 3 measure packages on the first day (0.24±0.41, 0.20±0.64, 0.47±0.17; F=1.659, P=0.206) and second day (0.27±0.27, 0.55±0.27, 0.47±0.39; F=2.236, P=0.123); significant difference was found on the third day (0.31±0.57, 0.44±0.46, 0.77±0.27; F=3.397, P=0.046), and measure package 3 showed the highest decline rate. Time to safety threshold of BI (decrease to less than 5) for the 3 measure packages were 3.58, 3.36, and 2.62 d, respectively, with the shortest time for measure package 3. Conclusion Combination of ultra-low-volume spraying, thermal fogging, residual spraying, slow-release agent, and environmental management works for Aedes control in the emergency response of the dengue fever outbreak.

Objective To survey dynamically the density of vector Aedes in the core area, warning area, and observing area, to evaluate the risk of dengue transmission based on the surveillance results, and to adopt control measures against vector Aedes. Methods From late August to late October, 2018, urban residential areas, rural residential areas, and nurseries or medical institutions were selected as surveillance habitats, and the densities of Aedes larvae in the observing area were surveyed by Breteau index (BI) every ten days; in the core area and warning area, communities with dengue cases received grid management, and the densities of vector Aedes were carried out emergency surveillance by BI and double bed net trap. Results The mean BI of observing area was 23.06. The mean BI varied widely in different counties (cities or districts). Ninghai county had the highest BI of 50.42, whereas Haishu district had the lowest BI of 4.81. The mean BI of urban areas (13.57) was significantly lower than that of suburban areas (33.84). By late October, the mean BI of the whole city declined to 14.09, especially in Haishu district (1.77) and Jiangbei district (3.54) (below the safety threshold, BI<5). The mean BI and bed net trap index in the core area and warning area were 3.27 and 1.02 mosquitoes per net per hour, respectively. Both BI and bed net trap index quickly declined and then leveled off after emergency investigation and settlement, and were below the safety thresholds after 2.61 and 1.57 days. Conclusion Based on the reasonable emergency surveillance of vector, combined with powerful prevention and control measures, the densities of dengue vectors can be effectively reduced to control the risk of dengue transmission.

Objective To investigate the density and seasonal fluctuation trend of Aedes mosquitoes in Ningbo, China, and to provide a reference for the prevention and control of Aedes-borne diseases. Methods From April to November, 2017, the double-layered mosquito net (DLMN) method and the Breteau index (BI) method were used to survey the adults and larvae of Aedes mosquitoes in residential areas, parks, and waste stations in the counties (cities and districts) of Ningbo. And the seasonal fluctuation trends of Aedes mosquitoes were analyzed. Results The mean net trap index of Aedes mosquitoes in Ningbo was 1.18 mosquitoes/net·hour, and the index was highest in September. Among all the above-mentioned habitats, the parks had the highest net trap index (1.23 mosquitoes/net·hour). The mean BI in surveillance area was 15.11, and the BI was highest (23.63) in September. Conclusion The risk of transmission of Aedes-borne diseases in Ningbo is high from June to September. Regarding the Aedes vector surveillance, using both DLMN and BI methods simultaneous can better assess the risk of dengue transmission.

Dengue viruses could be transmitted vertically by vector Aedes mosquitoes, and survive a long time in diapausing eggs and then disseminate with these eggs. Therefore, vertical transmission has been suggested to be a possible mechanism for the persistence of dengue fever viruses during adverse conditions for horizontal transmission. However, it is unclear how widespread it is in nature, and its importance in the epidemiology of this disease is still debated. Here, we review the literature on the relationships of viral vertical transmission and Aedes diapause, to discuss how dengue fever viruses survive during cold winter or inter-epidemic phase and then transit to next epidemic season. This review will provide some references for the research on dengue fever monitoring and controlling.

Objective Given that an outbreak of dengue was occurring in neighboring city of Ningbo, to reduce the risk of local transmission caused by imported cases, to strengthen monitoring of Aedes albopictus and to provide a basis for the control of dengue vector in Ningbo city. Methods The densities of Ae. albopictus larvae in residential quarters of cities or countryside and nurseries in 11 counties, cities or regions of Ningbo were monitored by Breteau index(BI) method from 2017-09-11 to 2017-11-10, and the relationships between mosquito densities and meteorological factors were analyzed by Spearman correlation analysis and multiple linear regression analysis. Results Almost all the BI was above 5, the Dengue virus trasmission threshold, among the monitoring sites. During most of the monitoring period, the BI was above 20. The BI of later monitoring declined, but still above dangerous threshold. The BI of urban districts(17.88) was significantly lower than that of suburb(31.44); The BI of nurseries(40.25) was higher than that of residential quarters of cities(13.10) or countryside(29.46). Mosquito densities were significantly associated with average temperature(R=0.899, P=0.015), especially average minimum temperature(R=0.943, P=0.005). Conclusion The densities of Ae. albopictus larvae were generally higher above the Dengue virus trasmission threshold, and there were potential risks of dengue epidemic in Ningbo city. The surveillance system should be strengthened, and multi-layered technology of prevention and control should be reserved. Besides, average temperature, especially average minimum temperature, had a significant influence on mosquito densities.

Objective Investigating the quantity and variation of Culex pipiens pallens larvae to weather condition, and water quality in an outdoor water treatment testing system in Shanghai, China. Methods Collecting mosquito larvae and pupae during May 10 ^th to November 27 ^th in 2015 and April 4 ^th to August 31 ^th in 2016, and recording the daily temperature, precipitation, weather, analyzing the TN, TP, TOC, BOD ₅ of water samples at the same time. Results The density of larvae started to increase when the daily minimum temperature reached 13.0℃, peaked when the daily temperature ranging 19.0 to 28.0℃, and collapsed after the daily maximum temperature higher than 31.0℃. The rapid increasing of density was accompanied with wet or cloudy weather, while the decreasing period was accompanied with sunny day or heavy rainfall. The correlation of Cx. pipiens pallens larvae density and TN, TP, TOC, BOD ₅, comprehensive pollution index of water quality was relatively positive. Conclusion Water quality, daily minimum and maximum temperatures and weather have impact on the breeding of Cx. pipiens pallens, especially daily maximum temperature.

【Abstract】 Objective To further explore the action mechanism of lambda?cyhalothrin by researching the effect of it to Superoxide dismutase (SOD) and Glutathione peroxidase (GPX) of Blattella germanica, and to provide theoretical basis and useful methods for the control and prevention of B.germanica. Methods Lambda?cyhalothrin with different concentrations was sprayed on B.germanica according to the method of GB 13917.1-13917.8－92, and the activities of SOD and GPX were determined by kits.  Results The induction of lambda?cyhalothrin with different concentrations to SOD and GPX varied with time, and the induction effect had a positive relationship with the concentrations of lambda?cyhalothrin. The relative activities of SOD and GPX appeared the trend of “rise?decrease?rise” within 144 h. Conclusion The lower concentration of lambda?cyhalothrin has obvious induction to SOD and GPX, and the increase of SOD and GPX activity has the relationship to the resistance and tolerance of cockroach to lambda?cyhalothrin.

Objective By studying the biochemistry indexs in Blattella germanica resistant monitoring,to know the resistance of B.germanica.Methods Field populations of B.germanica were captured from Jinan,Qingdao and Dongying.Beta cypermethrin at different concentration was sprayed based on the method of GB 13917.1,13917.8-92 for insecticide registered testing indoor effect.The enzymes activities were tested using kits.Results There were significant differant activities of AChE,SOD and GPx compared with cypermethrin treated population and susceptible strain,while the activities of Na-K-ATP _ase and Ca-ATP _ase weren't significantly different between them.Conclusion The activities of AChE,SOD and GPx may be effective indexes of resistant monitoring to beta-cypermethrin and Na-K-ATP _ase and Ca-ATP _ase activities can only be reference indexes.

Objective To more perfectly understand the operational mechanisms of α-cypermethrin and provide theoretical basis and useful methods by researching dosage effect and time effect between α-cypermethrin and acetylcholinesterase(AChE) activities in Blattella germanica.Methods Quantitative α-cypermethrin at different rate was sprayed based on the method of GB13917.1-GB13917.8-92 for insecticide registered testing indoor effect.The activities of AChE were determined by using Acetylcholinesterase(AChE) Kit.Results Inhibition of α-cypermethrin on AChE activities of Blattella germanica showed concentration gradient effect in 48 hours.The results showed the correlation of concentration of α-cypermethrin and inhibiting time effect on AChE activities of Blattella germanica in 144 hours and death rate of Blattella germanica in 72 hours was positive relationship.Conclusion AChE is one target of α-cypermethrin in Blattella germanica.Because of sensitivity decrease of AChE,target resistance is one of the important resistant mechanisms to α-cypermethrin.The activity of AChE in Blattella germanica may be one of the indices for determining resistant level to pyrethroid insecticides.