Objective To understand the composition of main vector species in Zibo City in 2022, master its density and seasonal fluctuation, so as to provide scientific basis for vector biological control in Zibo City. Methods Four vectors of mosquitoes, flies, mice and cockroaches were monitored in Zibo City.Mosquito surveillance was carried out by the mosquito lamp trapping method and the Breteau index (BI) method. Cage trapping method was used to monitor flies. The night snap trapping method was used outdoors for rodent surveillance.The method of sticky trapping was used for cockroach surveillance. The difference of species composition in different habitats was determined by Chi-square test or Fisher’s exact probability method. Results In 2022, the average density of adult mosquitoes was 11.81 mosquitoes/light·night, and the highest density was 32.51 mosquitoes/light·night in August; the dominant species was Culex pipiens pallens; As for the larvae, BI were all>10.00 in July and August, and >20.00 in September. The average density of flies was 12.51 flies/cage, and the density reached the peak of 66.98 flies/cage in July; Musca sorbens was the dominant species. In 2022, the average density of rodents was 1.15%, with the peak of rodent activity in September, and the dominant rodent species was Rattus norvegicus. In 2022, the average density index of cockroaches in the city was 3.15 cockroaches/sheet, with the peak occurring in September, and Blattella germanica was the dominant species. The composition ratio of mosquitoes, flies and mice in different habitats was different, and the difference was statistically significant ( χ ²=3 160.149, 1 029.005, 33.394, all P<0.001). Conclusion The main disease vectors in Zibo city were Cx. pipiens pallens, M. sorbens, R. norvegicus and B. germanica. with high densities during July to September in summer. Appropriate measures should be taken to control the density of the vectors to prevent the spread of vector-borne diseases.

Objective To analyze the changes in plague host animals and vector populations in Wenzhou, Zhejiang Province, China, so as to provide data support for plague prevention and control. Methods Descriptive epidemiological methods were used to analyze the distribution of plague hosts and vectors based on the surveillance data in Wenzhou from 2013 to 2022. The rates between groups were compared using the Chi-square test. The flea index distribution between groups was compared using the Kruskal-Wallis H test. The temporal trend of the flea index was determined using the Mann-Kendall trend test. The temporal trends of the flea infestation rate and small mammals capture rate were determined using the Cochran-Armitage trend test. Results From 2013 to 2022, a total of 37 851 small mammals were captured in Wenzhou, belonging to 15 species, 11 genera, 4 families, and 3 orders. The overall capture rate was 9.44 %. Suncus murinus (48.98 %), Rattus norvegicus (29.03 %), and R. tanezumi (9.32 %) were the dominant species. From 2013 to 2022, the capture rate of S. murinus showed an upward trend ( Z=-27.408, P<0.001), while the capture rates of R. norvegicus and R. tanezumi showed a downward trend (both P<0.001). A total of 17 144 small mammals were combed, and fleas were detected in 629 small mammals (3.67 %). The total number of fleas collected was 1 962, and the flea index was 0.11. The flea infestation rate between different small mammals was significantly different ( χ ²=875.254, P<0.001). A total of 33 761 animals were dissected, and no Yersinia pestis was detected and all negative for a total of 36 958 serum samples. Conclusions Epizootic plague in Wenzhou is at a resting state, but the risk of plague spread remains existing. It is necessary to further strengthen plague surveillance and emergency preparedness and response.

Objective To investigate mutations in the voltage-gated sodium channel gene ( VGSC) responsible for knockdown resistance (kdr) in Aedes aegypti and analyze the prevalence characteristics of the VGSC gene in the key areas of Ae. aegypti distribution in Yunnan Province, China. Methods Wild adult or larval Ae. aegypti samples were collected from 7 counties/cities (Yingjiang County, Ruili City, Zhenkang County, Gengma Dai and Va Autonomous County, Menghai County, Jinghong Municipality, and Mengla County) in Yunnan Province. The gene VGSC was amplified by direct sequencing to analyze the point mutation rate and the composition of combined mutations. The Chi-square test was used to compare the differences in the kdr mutation rate of VGSC gene between different loci and between different sexes of Aedes albopictus. Results The DNA was successfully extracted and VGSC gene were sequenced for a total of 561 Ae. aegypti mosquitoes (276 females, 242 males, and 43 larvae) in 7 counties/cities. Four point mutations were found in the VGSC gene. S989P, V1016G, and F1534C mutations were present in every county/city. The S989P mutation rate ranged from 71.43% to 100%, with a mean of 92.51% (95% confidence interval [ CI]: 90.33%- 94.70%). The V1016G mutation rate was 100%. The F1534C mutation rate was 55.81%-100%, with a mean of 85.38% (95% CI: 82.45%-88.32%). The Y1527F mutation was first detected in Ruili Municipality, Gengma and Zhenkang County, and the mutation rate ranged from 0 to 35.45%, with a mean of 8.73% (95% CI: 6.39%-11.08%). There were 4 types of co-occurring mutations: S989P+V1016G, V1016G+F1534C, S989P+V1016G+F1534C, and S989P+V1016G+Y1527F+F1534C. Single point mutations were not found. There were no significant differences in the mutation rates of 989, 1016, 1527, and 1534 loci and the composition ratios of combined mutations in female and male mosquitoes in six counties/cities except Yingjiang County. Conclusions The kdr mutation in the VGSC gene of Ae. aegypti in Yunnan Province is mainly characterized by multiple-point joint mutations, and a new Y1527F mutation appears. Kdr mutations surveillance in Ae. aegypti should be carried out regularly to grasp the changes in its resistance to insecticide targets in time.

Objective To investigate the species composition, population density distribution, and seasonal fluctuation of flies in Qingdao, China, and to provide a scientific basis for fly control. Methods Flies were monitored using the cage trap method. Fly species composition was analyzed using the chi-square test, and fly population density was analyzed using the Kruskal-Wallis H test. Results From 2017 to 2022, a total of 10 490 flies were caught, with a mean annual density of 12.14 flies/cage. The dominant fly populations were Sarcophagidae, Musca domestica, and Lucilia sericata, accounting for 22.73%, 17.58%, and 17.45%, respectively. The species composition of fly differed significantly in different years ( χ ²=4 863.573, P<0.001). The activity of flies spanned a long period from March to November. The seasonal peak of fly population density in different years all occurred in July, at 47.63, 32.13, 33.63, 23.00, 26.75, and 28.50 flies/cage, respectively, and there was a significant difference in the seasonal fluctuations of fly density between different years ( H=36.442, P<0.001). For different habitats, fly density was highest in farmers’ markets (15.27 flies/cage) and lowest in restaurant surroundings (7.26 flies/cage), with a significant difference in the density of each fly species between different habitats ( H=2.386, P=0.035). Among the dominant species, M. domestica had the highest density in residential areas (3.18 flies/cage), Sarcophagidae had higher densities in farmers’ markets (2.68 flies/cage), green belts (2.73 flies/cage), and residential areas (3.75 flies/cage), and L. sericata had the highest density in farmers’ markets (3.34 flies/cage). Conclusions Flies in Qingdao are mainly infested farmers’ markets and residential areas, peaking in July, and different fly species prefer different habitats. Fly seasonality, dominant species, and breeding characteristics should be considered in formulating targeted control measures to effectively reduce fly population density.

Objective To investigate the rodent species composition, density, and seasonality in different habitats based on the rodent surveillance program in Nanchang, China, so as to provide a basis for scientifically formulating rodent control strategies in Nanchang. Methods Three types of surveillance habitats including urban residential area, rural natural village, and special industry were chosen from 2017 to 2022. Rodent density was investigated by the night snap-trapping method. Descriptive methods were used to perform a statistical analysis of rodent species composition and seasonal variation of rodent density in three different habitats in Nanchang. With SPSS 26.0 and Excel 2021 softwares, descriptive methods were used to perform a statistical analysis of surveillance data, and the Chi-square test was used for comparison of rodent density across different years and habitats. Results A total of 104 121 effective traps were placed in Nanchang from 2017 to 2022, and 548 rodents were captured, with an average rodent density of 0.53%. The overall rodent density in the six years was statistically significant ( χ ²=34.857, P<0.001). A bimodal distribution with seasonal variation was found in the overall rodent density, the annual density of three dominant rodent species ( Rattus norvegicus, Mus musculus, and R. tanezumi), and the rodent density in residential areas and special industry habitats, while the rodent density in rural natural village habitats showed a unimodal trend, with the peak in July. The rodent density in rural natural villages (1.56%) was significantly higher than that in special industries (0.45%) and than that in urban residential areas (0.30%) ( χ ²=304.340, P<0.001). The dominant rodent species in urban residential areas and rural natural village habitats were R. norvegicus and R. tanezumi, while M. musculus predominated in special industry habitats (47.47%). The composition ratio of R. norvegicus in special industry and rural natural village habitats was decreasing year by year; the composition ratio of R. tanezumi in urban residential areas showed a decrease after increasing, while it was generally increasing in special industry and rural natural village habitats; the composition ratio of M. musculus in three different habitats showed an overall increasing trend. Conclusions The rodent density varies greatly in Nanchang from 2017 to 2022. The rodent density showed a bimodal distribution with seasonal changes and was high in rural areas. Specific control measures should be taken according to the changes in rodent species in different habitats to reduce the rodent density and the risk of rodent-borne diseases.

Objective To investigate and analyze the changes in tick density by time, region, host animal, and habitat based on tick surveillance results in Shaoxing, Zhejiang Province, China from 2017 to 2019, so as to provide a basis for developing tick prevention and control measures. Methods At six surveillance sites set in Shaoxing, the parasitic ticks were monitored by animal body surface inspection, and the questing ticks were monitored using the drag-flag method. Descriptive statistical analysis method was used to analyze the data. Results For parasitic ticks, the average tick index in Shaoxing from 2017 to 2019 was 0.53; by month, the highest tick index was 0.78 in September, and the lowest was 0.03 in March; by host animal, goats had the highest tick index (0.77), followed by rural dogs (0.21); and by region, the tick index in Shangyu District was the highest (1.59), while no ticks were detected in Yuecheng District. For questing ticks, the average density was 0.90 ticks/flag·100 m; by month, the highest density was 1.63 ticks/flag·100 m in September, and the lowest density was 0.10 ticks/flag·100 m in March; by habitat, the highest density was 6.57 ticks/flag·100 m on rural sloped grassland, followed by 0.09 ticks/flag·100 m around rural natural villages; and by region, the highest densities were in Shangyu District (5.67 ticks/flag·100 m) and Shengzhou (0.02 ticks/flag·100 m). Conclusions In Shaoxing, the density of questing ticks was highest in rural sloped grassland, and the density of parasitic ticks was highest on goats. In the areas with a high incidence of tick-borne diseases, targeted tick control measures should be taken based on the results of surveillance.

Objective To investigate Hantavirus infection and genotype characteristics in small mammals in Anhui Province, China. Methods From September 2021 to December 2022, small mammal specimens were collected in Anhui Province in accordance with the National Biovector Etiology Surveillance Program ( Trial). Hantavirus nucleic acid of small mammal’s lung specimens were detected by reverse transcription real-time fluorescence quantitative PCR, and for positive samples, full-length amplification, sequencing, and sequence analysis of the S fragment were conducted. Results A total of 4 075 specimens of 8 species of samll mammals were examined in 16 cities of Anhui Province. The dominant species were Rattus norvegicus (32.15%), Mus musculus (21.87%), R. tanezumi (21.72%), and Apodemus agrarius (20.86%). The positive rate of hantaviral nucleic acids was 1.47% (60/4 075), including Hantaan virus (HNTV) and Seoul virus (SEOV). From the 60 positive samples, 19 S sequences were obtained by cross-species PCR amplification. Genetic evolution analysis showed that HNTV was H5 and SEOV was S3 subtypes, respectively. The similarity of the nucleotide sequences was 72.00% to 100% and that of amino acid sequences was 83.00% to 100%, respectively. Conclusions HNTV and SEOV infections were present in small mammals in Anhui Province. It is necessary to strengthen Hantavirus surveillance in small mammals to provide a scientific basis for the prevention and control of hemorrhagic fever with renal syndrome.

Objective To investigate the species composition, density, and seasonal fluctuation of mosquitoes in Yancheng, Jiangsu Province, China, so as to provide a scientific basis for developing effective mosquito control measures and forecasting and early warning of mosquito-borne diseases. Methods Mosquito density was monitored by using the lamp trapping method in five types of habitats (urban residential areas, parks, hospitals, farmers’ houses, and livestock sheds) in Yancheng. The species composition, population density, and seasonal fluctuation of mosquitoes were analyzed. With SPSS 20.0 software, the Chi-square test was performed on the mosquito species composition ratios of different years and different habitats, analysis of variance was performed for different years, different species, and different habitats of mosquito densities, and trend analysis was performed for different years and different species of mosquito densities. Results From 2016 to 2023, a total of 132 432 female mosquitoes were caught in Yancheng, with an average density of 13.59 mosquitoes/light·night. Culex pipiens pallens/ quinquefasciatus, Anopheles sinensis, and Cx. tritaeniorhynchus were the top three mosquito species, accounting for 68.62%, 13.95%, and 12.09% of the total catches, respectively. There was a significant difference in the composition of mosquito species between different years ( χ ²=9 026.399, P<0.001). Mosquito density and trend changes differed significantly in different mosquito species (both P<0.001). By habitat, the highest mosquito density was in livestock sheds (28.37 mosquitoes/light·night), while the lowest mosquito density was in hospitals (7.84 mosquitoes/light·night), with significant differences in the species composition ratio and density of mosquitoes between habitats (both P<0.001). Seasonal fluctuations in mosquito density showed unimodal distributions for all habitats and for all species, peaking during June and September. Conclusions Cx. pipiens pallens/ quinquefasciatus, An. sinensis, and Cx. tritaeniorhynchus are the dominant species in Yancheng. Livestock sheds and farmers’ houses are the key places and June to September is the key time for mosquito control. Specific mosquito control measures should be taken based on the population distribution, density change, and seasonal fluctuation of mosquitoes.

Objective To verify the field efficacy of 0.2% curcumol baits against farmland rodents and determine the optimal dose. Methods A field experiment with 0.2% curcumol baits at three doses 1 500, 3 000, and 4 500 g/hm ² was carried out in the plague foci of Lijiang, Yunnan Province, China. The changes in rodent density,uterine development status, pregnancy rate, and litter size were investigated at 30, 60, and 90 days after baiting. The bait efficacy and intake level were calculated with the use of Excel 2010 software. Results The control effects of curcumol baits at 1 500, 3 000, and 4 500 g/hm ² groups were 47.06%, 51.87%, and 57.65% at 30 days, respectively; 50.00%, 63.64%, and 60.00% at 60 days, respectively; and 54.55%, 62.81%, and 50.91% at 90 days, respectively. The number of subadults decreased substantially, and the pregnancy rate and average litter size of female adult rodents also decreased. The curcumol bait intake coefficient of rodents was 0.77. No dead rodents or non-target organisms were observed during 15 consecutive days of investigation since the first day after baiting. Conclusion 3 000 g/hm ² of 0.2% curcumol baits is recommended for controlling farmland rodents based on the control effects and the economic threshold.

Objective To investigate the distribution of mosquito vectors in Hainan Province, China from 2020 to 2022, so as to provide common mosquito ecological surveillance data for analyzing the risk of transmission of imported mosquito-borne diseases after the initiation of China (Hainan) Pilot Free Trade Zone operations. Methods In 18 cities (counties) across the province throughout the years, adult mosquitoes were monitored using the light trap method and the double-layered mosquito net method, and larval mosquitoes were monitored using the Breteau index (BI) method. With the use of R 4.3.1 software, one-way analysis of variance (ANOVA) was performed to compare the mean values of different mosquito populations in different years and regions, and if the difference was significant, the least significant difference method was used for further pairwise comparison. Results From 2020 to 2022, a total of 12 240 lamps were set across Hainan Province, and 41 087 female mosquitoes were captured. The density of mosquitoes was 3.36 mosquitoes/light·night. The annual density fluctuated between 1.59 and 4.55 mosquitoes/light·night, and was significantly different in different years ( F=4.810, P=0.015). The net trap index for Aedes was 0.90 mosquitoes/net·hour. The annual fluctuated between 0.06 and 1.74 mosquitoes/net·hour, and there was no significant difference in the mean net trap index of different years ( F=2.697, P=0.082); The BI for Aedes larvae was 4.13. The annual BI fluctuated between 2.13 and 6.60, and the mean BI showed no significant difference between different years ( F=2.969, P=0.065). The mosquito density by the light trap method showed an obvious seasonal pattern, which was higher in summer than in winter; the density of Ae. albopictus also showed obvious seasonality, which was lowest during December to next February, and then increased to high levels during June to August, followed by a downward trend after August. There were significant differences in the mean annual values of adult mosquito density ( F=7.758, P<0.001) and BI ( F=11.630, P<0.001) between different dry and wet climate zones, but the net trap index showed no significant difference ( F=1.977, P=0.113). Conclusions The annual mosquito density, net trap index and BI were all at a low level in Hainan Province from 2020 to 2022, but mosquito density were high in some areas. It is necessary to pay close attention to the mosquito vector density after the closure of the free trade port, and strengthen the surveillance of the vector mosquitoes.

Objective To analyze epidemiological characteristics and outbreak of dengue fever in Yunnan Province, China, so as to provide a scientific basis for formulating effective prevention and control measures. Methods Relevant data on dengue fever cases and outbreaks reported in Yunnan Province during 2013-2022 were collected from the “Infectious Disease Surveillance System” and “Public Health Emergency Management Information System” of “China Disease Control and Prevention Information System”. The concentration method was used to analyze seasonal characteristics. Excel 2007 software was used to sort out the data. MapInfo 7.8 software was used to draw the map. SPSS 26.0 was used to analyze the correlation, and the Chi-square test was used to compare the rate or composition ratio. The descriptive epidemiological method was used to analyze the epidemiological characteristics and outbreak response to dengue fever. Results A total of 16 774 cases of dengue fever were reported in Yunnan Province from 2013 to 2022, including 11 944 local cases, 4 521 overseas imported cases, and 309 domestic imported cases, with an average annual reported incidence of 3.53/100 000. The disease showed a high incidence every other year. The concentration ( M) was 0.84, showing strong seasonality. Imported cases mainly occurred from June to October, and local cases mostly from August to November. The male-to-female ratio of imported cases was slightly higher than that of local cases ( χ ²=37.596, P<0.001). The majority of local cases were 30～<40 years old (20.14%), and the majority of imported cases were 20～<30 years old (27.58%). The local cases were found in 5 border prefectures (cities). The overseas imported cases were mainly from southeast Asian countries and African countries, and Myanmar, Cambodia, and Laos were the main source countries (96.81%). The domestic imported cases were mainly from Xishuangbanna Dai Autonomous Prefecture (85.76%). The majority of cases were farmers, commercial service personnel, cadres/retirees, housekeepers, job-waiting people, and students. Commercial service personnel accounted for the highest proportion in local cases (21.89%), while farmers accounted for the highest proportion in imported cases (39.90%). There was a significant difference in occupational distribution between imported cases and local cases ( χ ²=1 535.415, P<0.001). A total of 28 dengue fever outbreaks were reported from 2013 to 2022, including 1 major event and 27 general events. The number of reported cases accounted for 83.41% of the total number of cases, and each event involved an average of 499.71 cases. The median time from the onset of the first case to the verification of event occurrence was 7 (5, 9) days, and the median duration of the outbreak was 110 (27, 140) days. Twenty-five outbreaks occurred in villages/communities. Conclusions Dengue fever in Yunnan has obvious seasonal, aggregated, and regional distribution patterns. We need to further strengthen imported case management, disease vector surveillance and control, and the prevention and control of dengue fever in key areas.

Objective To investigate changes in the density, infestation rate, and insecticide resistance of Blattella germanica in Nanjing, China, so as to provide a theoretical basis for scientific and rational use of insecticides. Methods From 2012 to 2022, the density and infestation rate of B. germanica were monitored in the 12 districts of Nanjing, and the resistance of the samples to propoxur, beta-cypermethrin, deltamethrin, acephate, and chlorpyrifos was tested by using the residual film method. The data were processed using the Probit module of SPSS 22.0 software. Spearman’s rank correlation analysis was conducted to correlate year with density, infestation rate, and resistance ratio. Results From 2012 to 2022, the densities of cockroaches were 1.01, 1.62, 2.17, 1.36, 1.21, 0.77, 0.58, 0.39, 0.39, 0.29, and 0.24 individuals/trap, respectively; and the infestation rates were 20.79%, 28.80%, 32.45%, 28.89%, 17.31%, 10.92%, 6.73%, 5.64%, 4.67%, 5.00%, and 3.36%, respectively. The density and infestation rate reached their peaks both in 2014, and decline since 2015, showing significant negative correlations between the year of investigation and the density and infestation rate ( ρ=-0.897, P<0.001; ρ=-0.909, P<0.001). Propoxur resistance commenced at a low level in 2015, and the resistance ratio peaked at 4.73 in 2020, showing a significant positive correlation between the year and the resistance ratio ( ρ=0.929, P=0.003). Beta-cypermethrin resistance increased to a medium to high level since 2015, and the resistance ratio reached the peak of 40.53 in 2020, showing a significant positive correlation between the year and the resistance ratio ( ρ=0.821, P=0.023). Deltamethrin resistance increased to medium to high or even to extremely high levels since 2015, with no significant correlation between the year and the resistance ratio ( ρ=0.714, P=0.111). The levels of resistance to chlorpyrifos and acephate were low in general, with no significant correlation between the year and the resistance ratio ( ρ=-0.003, P=0.624; ρ=-0.771, P=0.072). Conclusions From 2012 to 2022, the density and infestation rate of B. germanica in Nanjing showed a downward trend, while the resistance to propoxur and beta-cypermethrin increased. The increasing resistance of B. germanica may lead to a rebound in its density and infestation rate, which should be paid more attention to.

Objective To evaluate the effectiveness of a device called “rodent station” for rodent monitoring and control in farmland. Methods This device was placed on the field ridge of Nanfan Breeding Base in Yazhou District, Sanya, Hainan Province, China. The feasibility of the device for rodent surveillance was determined by using the built-in snap traps to monitor rodent density at night. Its efficacy for farmland rodent control was tested through bait feeding method. The palatability of base baits for rodent control was tested by selective feeding. Results From September to December in 2023, a total of 91 small mammals were captured in the four catches, including Rattus losea, R. tanezumi, R. norvegicus, and Mus musculus (in the order of the number of catches from large to low). The capture rate of four catches were 8.75%, 8.33%, 7.50%, and 4.58%, respectively, with 47.66% of efficacy against rodent. The selective feeding results showed that rodents preferred paddy, corn grits, corn flour, and rice from most to least. Conclusion The “rodent station” can be used as a tool to monitor and control rodent density in farmland and other outdoor environments, although the operation method needs to be improved.

Objective To investigate the density, species composition, and seasonal fluctuations of mosquitoes in human settlements and surrounding environments in Liaoning Province, China from 2020 to 2022, so as to provide a basis for effective prevention and control of mosquito-borne diseases. Methods From May to October of 2020 to 2022, mosquitoes were monitored using the light trap method in residential areas, parks, hospitals, rural households, and livestock sheds in 14 cities. The surveillance data were analyzed using Excel 2016, ArcGIS 10.7, and SPSS 27.0 softwares. The Chi-square test was used to compare the composition ratio of mosquito species. The Levene's test was used to assess the homogeneity of variance of mosquito densities by year and by habitat. The Friedman test for multiple paired samples was used to compare their differences between groups. Results From 2020 to 2022, a total of 4 239 mosquito lamps were deployed in Liaoning Province, capturing 238 193 female mosquitoes. Anopheles sinensis was the dominant species, accounting for 40.22 % of the total mosquitoes, followed by Culex pipiens pallens and Aedes dorsalis, accounting for 22.11 % and 20.25 %, respectively. The total mosquito density was 56.19 mosquitoes/light·night. The mosquito densities of 2020-2022 were 45.67, 42.72, and 80.84 mosquitoes/light·night, respectively. The mosquito density of livestock sheds was the highest, reaching 206.48 mosquitoes/light·night, followed by rural households with a density of 17.04 mosquitoes/light·night, and the lowest was in residential areas with a density of 5.25 mosquitoes/light·night. The mosquito density of livestock sheds was highest for all species except for Ae. albopictus, which only appeared in residential areas, parks, and hospitals. Among the surveillance points in the province, Anshan had the highest mosquito density of 215.27 mosquitoes/light·night, followed by Yingkou with 157.28 mosquitoes/light·night, and Dalian had the lowest density of 3.11 mosquitoes/light·night. The overall seasonal fluctuation in mosquito density showed a single-peak curve, reaching the highest in early August with a density of 179.48 mosquitoes/light·night. The seasonality of mosquito density differed significantly between different years ( χ ²=36.440, P<0.001) and between different habitats ( χ ²=26.272, P<0.001). Conclusions An. sinensis, Cx. pipiens pallens, and Ae. dorsalis are the dominant species in human settlements and surrounding environments in Liaoning Province. Mosquito density in rural habitats is high, especially in livestock sheds, which are major breeding sites and need strengthened mosquito control. Comprehensive prevention and control measures should be taken before the peak period of mosquito activity from June to August, to reduce mosquito density and the risk of mosquito-borne diseases.

Objective To evaluate and compare the efficacy of polydimethylsiloxane liquid film against the larvae and pupae of Culex pipiens quinquefasciatus, Aedes albopictus, and Ae. aegypti at different instars under laboratory conditions. Methods Thirty samples each of larvae of different instars and pupae were selected and placed in water containing the liquid film (1 ml/m ²). The growth,development,and death of the larvae or pupae were observed in a laboratory environment or in an artificial incubator at different temperatures. The data were organized and analyzed using Excel 2016 and SPSS 27.0 softwares. The survival curves of larvae or pupae exposed to the liquid film between different groups were compared using the log-rank test. The length of larvae was compared using the independent samples t-test. Results After exposure to the 1 ml/m ² liquid film,the median lethal times for the larvae at Ⅰ-Ⅱinstars of Cx. pipiens quinquefasciatus, Ae. albopictus, and Ae. aegypti were 2.67, 7.04, and 6.45 d, respectively; for the larvae at Ⅲ-Ⅳ instars, the values were 0.53,1.64, and 1.71 d, respectively; and for the pupae, the values were 96.68,115.54, and 109.77 min, respectively. After 7 days of rearing, the mean larval lengths for Cx. pipiens quinquefasciatus, Ae. albopictus, and Ae. aegypti exposed to the liquid film were (3.28±0.40), (3.17±0.61), and (3.21±0.47) mm, respectively, which were significantly shorter than their respective control groups (all P<0.001). Across the temperatures of 20, 25, 30, and 35 ℃, the mortality rates of larvae in the liquid film groups increased with rising temperatures:the mortality rates on the first day were 66.67 %, 71.11 %, 91.11 %, and 100 % for Cx. pipiens quinquefasciatus, respectively; 8.89 %, 30.00 %, 55.56 %, and 81.11 % for Ae. albopictus, respectively; and 14.44 %, 25.56 %, 56.67 %, and 75.56 % for Ae. aegypti, respectively. Conclusions The polydimethylsiloxane liquid film can well control the larvae and pupae of the three mosquito species and impede larval growth and development, and high temperatures can enhance the effectiveness. The polydimethylsiloxane liquid film is suitable for controlling various types of mosquitoes.

Objective To select palatable rodenticide baits, so as to provide support for reducing time invested and improving rodent control quality in large-scale rodent control activities. Methods Wax block baits, rice baits, corn baits, wheat baits, and peanut baits containing 0.005% brodifacoum were each paired up with a type of bait base (naturally dried peanuts) in a 1∶1 ratio. The baits were placed in a saturated manner. Bait consumption was monitored and recorded consecutively for seven consecutive days. Analysis of variance and bivariate correlation analysis were performed. Results The 7-day cumulative feeding coefficient (FC) was 0.57 for the peanut baits, indicating good palatability; 0.18 for the rice baits, 0.18 for the wax blocks, and 0.17 for the corn baits, indicating moderate palatability; and 0.10 for the wheat baits, indicating poor palatability. There were significant differences in the 7-day cumulative FC of different baits in paddy field ( F=25.340, P<0.001), residential area ( F=5.667, P=0.002) and forest habitat ( F=3.190, P=0.022), and the 7-day cumulative FC of peanut bait was the highest in the three habitats, which was 0.69, 0.54 and 0.49, respectively. The corn baits also showed good palatability in residential areas with a 7-day cumulative FC of 0.41. Conclusion Before starting construction at construction sites in the eastern coastal area of Shanghai, China, peanut baits containing brodifacoum can be used for large-scale rodent control work, which can improve the efficiency of rodent control.

Objective To investigate the current situation of vector control capacities of municipal and county-level centers for disease control and prevention (CDCs) in Shandong Province, China, so as to provide a basis for actively responding to the new situation of the prevention and control of vector-borne infectious diseases and improving vector control capacities of Shandong Province. Methods Through on-site interviews and questionnaire surveys, the information was collected on the vector control professionals and laboratory equipment of CDCs at the municipal and county levels in Shandong Province. Data were analyzed using WPS 2010 and SPSS 19.0 softwares. The t test or Wilcoxon’s rank-sum test was used for comparison of continuous data between groups, and the χ ² test was used for comparison of count data between groups. Results In Shandong Province, the average numbers of full-time personnel engaging in vector surveillance and control at municipal and county-level CDCs were 4.10 and 1.94, respectively. Among the professionals, junior and intermediate titles were more common, accounting for 34.43% and 36.79%, respectively; 46.70%(99/212) majored in preventive medicine (public health); and the majority had 1-5 years of work experience, accounting for 58.49%. The work mainly focused on carrying out ecological surveillance of disease vectors, and the vast vector laboratories were only able to carry out classification and identification disease vectors; The county-level CDCs undertook 59.38% of the training, and the average annual number of academic papers and scientific research achievements was 5.2 and 0.8, respectively. Conclusions In order to cope with the new challenges facing vector biological control, it is necessary to increase financial investment, strengthen talent and technical reserves, and strengthen scientific research and training. Professional and technical personnel should be based on the existing surveillance projects to strengthen data analysis and utilization, take more action in publicizing the knowledge of vector biological control, and continuously improve the level of social services.

Objective To investigate the density and seasonality of the dengue vector Aedes populations in Henan Province, China, so as to provide a scientific basis for the risk assessment, monitoring, early-warning, and control of dengue fever. Methods From May to October of 2019 to 2022, Aedes vectors were monitored using the Breteau index (BI) method at 14 surveillance sites of Henan Province. Excel 2010 software was used to pool data, determine risk levels, and calculate the seasonal index. SPSS 25.0 software was used to perform the t-test and analysis of variance to compare the BI of different years and regions. Results The BI of Aedes mosquitoes from 2019 to 2022 were 15.31, 14.27, 11.34, and 12.32, respectively. The peaks occurred in July and August. Among 330 monitoring tasks over the four years, a regional spread risk was indicated in 85 (25.76%), an outbreak risk indicated in 70 (21.21%), a transmission risk indicated in 77 (23.33%), and no risk indicated in 98 (29.70%). The proportion of areas reaching a regional spread risk in southern Henan Province was higher than that in the northern part and along the Yellow River. The BI results of 2020, 2021, and 2022 were not significantly different from that of 2019 (all P>0.05). The BI showed no significant difference between regions (all P>0.05). Conclusions The density of Aedes mosquitoes is high in Henan Province, and there is a potential risk of dengue transmission in the peak season of Aedes for most surveillance sites. The number of imported dengue cases is expected to increase substantially in the future, highlighting the need for close attention to domestic and international dengue changes and emergency response and preparedness.

Objective By analyzing the surveillance data of host animals of hemorrhagic fever with renal syndrome (HFRS) in Guyuan, Ningxia Hui Autonomous Region (Ningxia), China from 2015 to 2021, to investigate the distribution of host animals of HFRS in Guyuan and their infection with viruses, so as to provide a basis for prevention and control, early warning and prediction of human epidemic in this region. Methods Small mammal trapping in field and residential areas in spring and autumn was carried out annually in accordance with the National Hemorrhagic Fever with Renal Syndrome Monitoring Program in the Jingyuan, Pengyang, Xiji, and Longde Counties and Yuanzhou District of Guyuan from 2015 to 2021. The density, distribution, and species composition were monitored by the night trapping method and analyzed, and the lung and blood specimens of small mammals were collected for antigen and antibody detection. The SPSS 23.0 software was used for statistical analysis, counting data were expressed as rates, and were compared with the Chi-square test ( P<0.05 indicates a statistically significant difference). Results From 2015 to 2021, a total of 5 515 small mammals were captured in Guyuan, with a mean density of 2.00%. The density of small mammals in the field areas (2.18%) was statistically higher than that in the residential areas (1.71%)( χ ²=55.920, P<0.001). The density of small mammals was statistically different across years and between different counties (districts) in the field areas ( χ ²=991.300, 1 202.179, both P<0.001); the dominant rodent species in Jingyuan County, Yuanzhou District, and Longde County were Apodemus agrarius, the dominant rodent species changed from A. agrarius to Rattus norvegicus in Longde county, and the dominant rodent species in Xiji County and Pengyang County were Cricetulus longicaudatus and Mus musculus, respectively. The density of small mammals was statistically different across years and between different counties (districts) in the residential areas ( χ ²=326.600, 430.500, both P<0.001), and the density of small mammals was generally below 5%. The dominant rodent species in Jingyuan, Xiji, Longde, and Pengyang were all M. musculus, and the dominant rodent species in Yuanzhou was R. norvegicus, with the proportion increased year by year. From 2018 to 2020, the density of small mammals showed a downward trend in the field and residential areas of Jingyuan and Longde, the field areas of Yuanzhou and Xiji, and the residential areas of Pengyang. The density of small animals increased statistically from 2020 to 2021 in the field and residential areas of Yuanzhou and Longde and in the field areas of Pengyang (all P<0.05). The infection rate (antibody positivity rate) of small mammals was 5.48 times the virus-carrying rate (antigen positivity rate) in the 7-year period; the virus-carrying rate of small animals was highest in Jingyuan County (1.05%), and the infection rate of small mammals was highest in Longde County (10.61%). The infection rate of small mammals in residential areas was statistically higher than that in field areas ( χ ²=12.675, P=0.008), while Hantavirus carrying of small mammals was only detected in the field areas. The virus-carrying rate of A. agrarius (2.94%) was higher than its infection rate (1.96%), and the infection rate of R. norvegicus (3.20%) was higher than its virus-carrying rate (0). Conclusions In recent years, the density of small mammals in Guyuan of Ningxia was generally low, but showed a slight increasing trend in the past two years; the density in the field areas was higher than that in the residential areas. The dominant rodent species were mostly A. agrarius in the field areas and M. musculus in the residential areas. The virus-carrying rate and infection rate of rodents increased significantly in 2021, suggesting that although the density, distribution, and composition of host animals of HFRS in Guyuan of Ningxia have not changed significantly, we still need to be vigilant for outbreaks of human epidemics.