Objective To analyze the data of reported cases of vector-borne diseases (VBDs) in China in 2005-2020, and to investigate the epidemic characteristics and trend of VBDs, challenges in prevention and control, and related coping strategies. Methods The descriptive epidemiological method was used to analyze the data of reported cases of VBDs in China in 2005-2020, and the challenges in prevention and control and related coping strategies were determined based on the epidemic characteristics of VBDs, current policies, and related literature domestic and abroad. Results A total of 905 092 cases of 14 VBDs were reported in China in 2005-2020, among which malaria, scrub typhus, and hemorrhagic fever with renal syndrome (HFRS) accounted for 66.94%, the ten notifiable VBDs accounted for 76.01%. A total of 5 076 death cases were reported, among which the death cases due to Japanese encephalitis (JE), HFRS, severe fever with thrombocytopenia Syndrome (SFTS), and malaria accounted for 93.26%. The incidence of VBDs fluctuated and decreased in 2005-2020. The number of cases showed two significant peaks in 2006 and 2014-2015. The Mann-Kendall trend test showed a significant trend of reduction in JE, malaria, typhus, and leptospirosis ( P<0.01) and a significant trend of increase in SFTS and scrub typhus ( P<0.01). At the same time, the incidence of VBDs showed marked seasonality with a peak in October. About 2 165 districts/counties reported VBDs annually, mainly in the east of the Heihe-Tengchong line. The Mann-Kendall trend test showed that the number of districts/counties reporting such cases tended to increase with no significance ( P=0.367). Over the past 16 years, the number of cases of vector-borne diseases tended to decrease in northeast China, while this number tended to increase in southwest China. Different diseases had different ages of onset, and the peak age of onset of VBDs was 20-44 years. The male population tended to have a higher incidence rate than the female population. Conclusion The number of cases of VBDs tends to decrease with fluctuation in China, but it still remains at a relatively high level, and the epidemic area tends to expand, with continuous increases in the incidence rate or mortality rate of some VBDs. As for the new challenges in the control of VBDs, it is necessary to implement related strategies and measures including the integrated vector management and sustainable vector management, so as to further reduce the morbidity and mortality of VBDs and achieve the targets and goals of Health China and Global Vector Control Strategies.

Objective To test and compare the speed of death of Blattella germanica and Periplaneta americana treated with six active ingredients, and to provide theoretical basis for consumers' experience. Methods Using the open square box method, 30 test insects were starved for one day had allowed access to cockroach baits containing each of the six effective components. The number of dead insects was counted at regular time intervals, and LT ₅₀ and LT ₉₅ were calculated according to the weighted linear regression method. Results Without other feed, the LT ₅₀ for B. germanica was in the order of 0.5% dinotefuran>2.5% imidacloprid>1.5% propoxur>0.05% fipronil>0.2% chlorpyrifos>0.1% indoxacarb, and the order of the LT ₅₀ for P. americana was 2.5% imidacloprid>0.05% fipronil>0.2% chlorpyrifos>1.5% propoxur>0.1% indoxacarb. The LT ₉₅ for B. germanica was in the order of 0.5% dinotefuran>2.5% imidacloprid>0.05% fipronil>0.2% chlorpyrifos>0.1% indoxacarb>1.5% propoxur, and the LT ₉₅ for P. americana was in the order of 0.2% chlorpyrifos>0.05% fipronil>0.1% indoxacarb>1.5% propoxur>2.5% imidacloprid. Dinotefuran had almost no toxic effect on P. americana. Cockroaches fed less on the diets of dinotefuran, imidacloprid and propoxur, which had a faster death rate in the early stage, and fed more on the diets of chlorpyrifos, fipronil and indoxacarb, which had a slower death rate in the early stage. Conclusion On the whole, cockroach baits with different active ingredients had different lethal rates to different species of cockroaches. Dinotefuran, imidacloprid and propoxur were quicker to kill B. germanica, while chlorpyrifos and fipronil were quicker to kill P. americana.

Objective To analyze the ecological surveillance results of Aedes vector in 12 provinces (autonomous regions or municipalities) in China in 2020-2021, and to provide a scientific basis for risk assessment, prediction, early warning, and control of Aedes-borne diseases. Methods The surveillance data of larval and adult Aedes densities at the special investigation sites of Aedes vector in 12 provinces (autonomous regions or municipalities) in China were collected and statistically analyzed by SPSS 18.0 software. Results In 2020-2021, the mean Breteau index (BI) was >10.00 in Hainan, Zhejiang, and Hunan provinces and >5.00 in Guangxi Zhuang Autonomous Region (Guangxi) and Yunnan, Henan, and Shandong provinces. The mean mosq-ovitrap index (MOI) was >5.00 in Guangxi, Guangdong, Hainan, and Shandong. The mean net trap index was ≥2.00 mosquitoes/net·hour in Henan, Hubei, and Shandong and >1.00 mosquito/net·hour in Guangxi, Guangdong, Hainan, Yunnan, Fujian, and Hunan. There were no statistical differences in BI, MOI, and net trap index between class I provinces (Guangdong, Hainan, Guangxi, Fujian, Yunnan, and Zhejiang) and other classes of provinces ( t=0.766, 1.030, and -0.745, all P>0.05). The mean BI in 2020-2021 was higher than that in 2017-2019 in Guangdong, Guangxi, Yunnan, and Shandong, but lower than that in the three years in other provinces. The Aedes vector was found to be active throughout the year at the investigation sites in Guangdong, Hainan, Guangxi and Yunnan, from March to December in Fujian, Zhejiang, and Hubei, and from April to November in Chongqing municipality, Shandong and Henan, and from April to December in Jiangxi. The results of BI and MOI were inconsistent in Yunnan, Guangxi, and Hubei. During the study period, the BI of Aedes vector was >5.00 in areas where dengue outbreaks and local cases occurred, and >10.00 in Ruili city in Yunnan, Cenxi city of Wuzhou in Guangxi, and Sanjiao town of Zhongshan in Guangdong; the net trap index in Cenxi city of Guangxi was >2.00 mosquitoes/net·hour. Conclusion In 2020-2021, the mean Aedes density in the provinces with local cases of dengue fever in China was high, with spatio-temporal heterogeneity among different regions. It is suggested that in the local transmission areas of dengue in China, it is necessary to adjust moderately annual surveillance periods, to continuously strengthen Aedes vector surveillance and risk assessment, and to systematically sort out the ecological investigation results of Aedes vector, so as to provide a scientific basis for the revision and improvement of Aedes vector surveillance scheme and the outbreak control of Aedes-borne diseases in China.

Objective To analyze the policies,strategies,techniques,actions,and achievements in the surveillance and control of vectors and vector-borne diseases in China since 2012. Methods Descriptive epidemiological methods were used to analyze and summarize the epidemiologic situation and challenges of vectors and vector-borne diseases,the surveillance of vectors,and the advances in the control of vectors and vector-borne diseases in China in the past ten years.The Mann-Kendall test was used to analyze the trend of the incidence rate of vector-borne diseases in the past decade using R 4.0.4 software. Results A series of policies,strategies,measures,and techniques were formulated and released for sustainable vector management in China in the past decade.The vector surveillance program in China had been continuously upgraded and improved,and a national vector surveillance network integrating ecology,etiology,and insecticide resistance had been established and improved.The number of national vector surveillance sites (1 097) in 2021 was increased by 54 times,and the funds input in national vector surveillance was increased by 127 times.Direct network reporting was realized for surveillance data,and there was a significant increase in the timely utilization rate of surveillance data,which provided better support for risk assessment,prediction and early warning,decision making,and control effect evaluation.The total annual incidence rate of vector-borne diseases in China in 2021(3.060/100 000) was reduced by 8.66% compared with that in 2007-2011(3.350/100 000),and the total annual mortality rate of vector-borne diseases in 2021(0.016/100 000) was reduced by 33.33% compared with that in 2007-2011(0.024/100 000).China had achieved the goal of malaria elimination and mitigated the accelerating increases in the incidence rates of dengue fever,scrub typhus,and severe fever with thrombocytopenia syndrome. Conclusion In 2012-2021,leapfrog development has been achieved for the policies,strategies,techniques,and actions for the surveillance and control of vectors and vector-borne diseases in China,and there are significant reductions in the incidence and mortality rates of vector-borne diseases.In view of the natural and social driving factors at present,the prevention and control of vectors and vector-borne diseases still face severe challenges,and therefore,it is urgent to further promote the strategies and measures for sustainable vector management,implement Global Vector Control Response 2017-2030,build proactive defense based on"reverse microbial etiology",so as to prevent and control major vector-borne diseases.

In 2021, the national surveillance of rodent-borne pathogens of disease vectors had been started up, and a total of 123 prefectures were selected as national surveillance sites. Sampling was completed at 95 surveillance sites. A total of 17 910 rodent specimens were collected, and 16 891 of them were tested. The completion rate of pathogen detection was 94.31%. The overall infection rate of eight monitored rodent-borne pathogens around China was 2.43% (407/16 716) for Hantavirus, 0.02% (4/16 154) for Dabie bandavirus (i.e., severe fever with thrombocytopenia syndrome virus), 5.75% (624/10 850) for Leptospira interrogans, 0.11% (5/4 470) for Rickettsia mooseri, 0.05% (5/10 790) for Orientia tsutsugamushi, 2.39% (75/3 136) for Bartonella, and 0.04% (2/5 075) for Anaplasma phagocytophilum. Francisella tularensis was not detected. More than ten species of rodents were found to be infected with different pathogens in 18 provinces across China. The infection rates of pathogens in rodents in southern regions were relatively high, and the positive rates of pathogens carried by various rodents differed. Rattus norvegicus and Apodemus agrarius were the species in which the most pathogens were detected.

Objective To formulate a catalogue of alien vectors and pathogenic organisms for early warning and effective prevention of alien species invasion. Methods The authors searched literature, online databases, and published catalogues for alien vectors and pathogens that can seriously threaten the health of human and animals and agricultural and ecological security. They were evaluated for the risk of invasion to China by using a suitable habitat prediction model and a comprehensive evaluation system of multiple indicators. Candidate species with the potential of invasion were included in this catalogue. Results A total of 304 alien species were screened out and listed in this catalogue for China, including 69 vectors and 235 pathogenic organisms. Among them, 275 species (47 vectors and 228 pathogens) had high probability of invading China. Conclusion This catalogue can be used as an early warning directory to prevent alien vectors and pathogenic organisms from invading China, which provides a reference for relevant departments to formulate preventive management strategies and measures.

Dengue fever is a mosquito-borne viral infectious disease that is widely distributed in urban or peri-urban areas in the tropical, subtropical, and warm temperate zones worldwide and threatens the health of populations in more than 100 countries and regions. Global climate change, urbanization, and urban population growth have created favorable conditions for the spread of dengue fever virus. At present, due to a lack of vaccines applicable for mass vaccination, Aedes vector control is the main measure for the prevention and control of dengue fever, and accurate and timely risk prediction for dengue fever can provide an important basis for precise prevention and control, and decision-making. In recent years, the development of geospatial big data promotes the identification of the driving factors for dengue fever at different spatial and temporal scales, and the advances in artificial intelligence, especially the emergence of various deep learning networks, provide new techniques for the risk prediction of dengue fever. Through a comprehensive analysis of the various types of driving factors for dengue fever and their mechanism of action, geospatial big data, and artificial intelligence techniques, this article elaborates on the application of geospatial big data in identifying the driving factors for dengue fever from the aspects of urban land use, climate and environment conditions, and population movement, as well as the current status of the application of artificial intelligence algorithms in predicting the risk of dengue fever transmission. Based on the current research status of geospatial big data and artificial intelligence, it is proposed that future research should develop spatiotemporal risk predictive models at different spatial and temporal scales and the performance of such models should be evaluated in terms of the difference between predicted and true values, the spatiotemporal aggregation patterns of dengue fever, and the actual needs of dengue fever prevention and control.

Objective To investigate the changes in species composition and number of small rodents in natural plague foci of Hebei province, China, from 1990 to 2020, and to provide a basis for the prediction and early warning of animal epidemics in the plague foci. Methods Excel 2010 software was used to summarize and count the monthly and annual surveillance data on small rodents, and the concentration degree method was used to analyze the seasonal distribution of small rodents. Results From 1990 to 2020, a total of 112 205 clamps were placed and 1 322 rodents were caught, with a mean capture rate of 1.18%. The highest capture rate (2.30%) occurred in the year 2019, followed by the year 2004 (2.20%), and the lowest capture rate (0.41%) occurred in the year 2000. There were 9 years (1990, 1999, 2004, 2012-2016, and 2019) when the capture rate was higher than the mean value. A total of 11 species of rodents were captured, belonging to 8 genera and 4 families, among which Cricetulus barabensis (63.31%) was the dominant species. The highest number of small rodent species (8 species) was observed in 2014, and the fewest (1 species) in 1991. The number of small rodents were distributed evenly throughout the year ( M=0.13), and the months with relative high numbers were June (247/1 322, 18.68%), July (259/1 322, 19.59%), and October (250/1 322, 18.91%). The interannual distribution of the number of the dominant species, C. barabensis, had been consistent with that of small rodents, with the highest number seen in 2019. The number distribution of C. barabensis showed seasonality ( M=0.30) and the number was relatively high in summer and autumn, with the highest number in October (0.98%), followed by July (0.82%), June (0.71%), and November (0.71%). Conclusion The species number of small rodents has a rising tendency, with rich species composition. The significant influence of the changing trend in the small rodent species on rodent epidemic outbreaks and spread should be highlighted.

Objective To investigate the changes in population number and structure of parasitic fleas of Meriones unguiculatus in the natural plague focus Kangbao pasture in Hebei province, China from 1981 to 2020, and to provide a basis for early warning of epizootics in this focus. Methods Excel 2010 software was used to perform year-by-year and month-by-month analyses on the data of rat body fleas, burrow fleas, and nest fleas of M. unguiculatus. The concentration degree method was used to analyze the seasonal distribution of parasitic fleas. Randomized block analysis of variance was used to analyze the flea index of different types of parasitic fleas of M. unguiculatus. Results From 1981 to 2020, a total of 4 046 fleas were collected, belonging to 17 species of 11 genera under 3 families. A total of 122 Xenopsylla conformis conformis fleas were collected from M. unguiculatus bodies from 2018 to 2020, accounting for 7.24% (122/1 684). There was no significant regularity in the infestation rate changes of body fleas, burrow fleas, and nest fleas, but the infestation rates of body fleas and nest fleas were higher than the average level in 1995, 2002-2003, 2005, and 2017-2018 when epizootics occurred. The concentration degree method found that both body fleas ( M=0.3) and nest fleas ( M=0.3) of M. unguiculatus had certain seasonality, and they tended to change inversely-one rose as another fell; M. unguiculatus burrow fleas had strong seasonality ( M=0.7), with flea density higher in summer and autumn and lower in winter and spring. The randomized block analysis of variance showed a significant difference in the flea index between different types of parasitic fleas of M. unguiculatus ( F=3.515, P=0.023), and multiple comparison showed significant differences in the flea index between any two types of body fleas, burrow fleas, and nest fleas (all P<0.05). Conclusion Plague epizootics were associated with the parasitic flea infestation rate of M. unguiculatus in the natural plague focus Kangbao pasture of Hebei province from 1981 to 2020, which provides a theoretical basis for targeted flea control measures to prevent plague.

Objective To analyze the historical development and future hot spots of dengue fever research in China, and to provide a basis and reference for research, prevention and control of dengue fever in China. Methods Data were obtained from China National Knowledge Infrastructure database; "dengue fever" and "dengue virus" were used as subject terms for the search of dengue fever-related references collected (from January 1, 2011 to April 10, 2021) in the database; a total of 1 738 references were retrieved and 1 394 references were included. Excel 2019 and CiteSpace 5.6.R5 softwares were used for analysis of the 1 394 references by authors, journals, and institutions; meanwhile, visual analysis and evolution were performed on the key words, burst terms, and timelines for the development of dengue fever-related research in China. Results During 2011-2021, the number of publications on dengue fever in China could be divided into three phases with an overall upward trend (2011-2013, 2014-2016, and 2017-2021); main publication institutions were centers for disease control and prevention, universities, and research institutes; hot spots in the field of dengue fever were dengue virus, Aedes albopictus, epidemiology, and surveillance. Conclusion In recent years, there is a growing trend of performing dengue fever-related research in China, while many challenges still exist. Governments and health authorities in high-risk areas should arouse the awareness of dengue fever among common populations; research personnel should focus on the treatment, prevention and control strategies, and risk assessment of the disease, and perform in-depth studies on the surveillance, early warning, and the cost-effectiveness in prevention and control of dengue fever.

Objective To investigate the resistance of Aedes albopictus to commonly used insecticides, after control of a dengue fever outbreak in Chongqing, China, 2019, and to provide a basis for controlling mosquito-borne diseases including dengue fever and Aedes vector. Methods From May to October, 2020, Ae. albopictus mosquitoes were collected from parks or waste tire piles in 6 districts (counties) of Chongqing and were reared for 1-2 generations in laboratory, and the larval dipping method and the adult exposure tube method were used for insecticide resistance surveillance. Results Ae. albopictus larvae from each investigation site of Chongqing had varying degrees of sensitivity to commonly used insecticides, with a resistance ratio of 0.46-7.32. The resistance ratio was 0.46-4.92 for temephos and 0.82-7.32 for propoxur. Adult Ae. albopictus mosquitoes from each investigation site of Chongqing developed varying degrees of resistance to deltamethrin, permethrin, beta-cypermethrin, and lambda-cyhalothrin, with a 24-hour death rate of 5.88%-78.22%. The adult Ae. albopictus mosquitoes in the field of Wanzhou district developed suspected resistance to bendiocarb and fenitrothion, and those in the field of Dazu district developed suspected resistance to chlorpyrifos; the adult Ae. albopictus mosquitoes in the field of the remaining investigation sites were sensitive to propoxur, bendiocarb, malathion, fenitrothion, and chlorpyrifos. Conclusion Ae. albopictus adult mosquitoes from each investigation site of Chongqing develop resistance to pyrethroids, and Ae. albopictus larvae from some investigation sites develop a low level of resistance to temephos and propoxur. It is recommended to regularly monitor the resistance level and changing trend of Ae. albopictus and to select corresponding insecticide use strategies according to the insecticide resistance of Ae. albopictus at different developmental stages.

Objective To investigate the basic concept of "rodent-borne diseases" suitable for national vector surveillance and the list of "rodent-borne diseases" in China. Methods Related keywords were used to search for the articles on "rodent-borne diseases" in the databases and websites of SinoMed,CNKI,Wanfang Data,Super Star Digital Library,PubMed,and Web of Science,and the definition of "rodent-borne diseases" was summarized to determine its concept and coverage. A total of 27 diseases were selected to form the list of major "rodent-borne diseases" in China for expert consultation. Results A total of 178 references were used to formulate the basic concept of "rodent-borne diseases" and its inclusion criteria,and 18 experts consulted all agreed to the concept of "rodent-borne diseases". The information table of "rodent-borne diseases" in China was developed, including 5 viral diseases,12 bacterial diseases, and 8 parasitic diseases. Conclusion "Rodent-borne diseases" are a group of infectious diseases that seriously affect human health,and its basic concept and inclusion conditions are proposed to provide a reference for the comprehensive surveillance of disease-related pathogens carried by rodents and promote the establishment of more perfect control strategies.

Objective To investigate the species composition and distribution of ticks and the pathogens carried by the ticks in Shanghai, China, and to provide a scientific basis for developing local prevention and treatment measures for ticks and tick-borne diseases. Methods The four commonly used English and Chinese databases of CNKI, Wanfang Data, VIP, and PubMed were used to collect the articles on tick in Shanghai in the past twenty years (2000-2020), and related information was extracted to analyze the species and distribution of ticks and the pathogens carried by them at different investigation sites in Shanghai. Results The tick species reported in Shanghai were Rhipicephalus sanguineus, Haemaphysalis longicornis, H. campanulata, H. flava, and Amblyomma varanense, among which R. sanguineus was the most common and widely distributed tick species in Shanghai, followed by H. longicornis. The host animals for tick mainly included dogs, sheep, and rodents. Pathogens including Ehrlichia, Babesia, Coxiella, spirochete, and Brucella were detected in the tick species distributed in Shanghai. Conclusion Various tick species are observed in Shanghai, and multiple pathogens are detected, suggesting that there is a potential risk of the transmission of tick-borne diseases.

Objective To investigate the density, species composition, dynamic variation, and changing trend of four major vectors in Liaoning province of China, i.e., rodents, mosquitoes, flies, and cockroaches, and to provide a scientific basis for the prevention and control of vectors and vector borne infectious diseases. Methods From January to December in 2020, the night trapping method and the sticky trap method were used for the surveillance of rodents and cockroaches in odd months, and the light trapping method and the cage trapping method were used for the surveillance of mosquitoes and flies from May to October, respectively. Vector surveillance data were collected from the surveillance sites in 14 prefectures of Liaoning province, and Excel 2010 and SPSS 23.0 softwares were used for statistical analysis. Results In 2020, the density of rodents in Liaoning province was 0.91 rodents/100 traps and reached the peak of 1.14 rodents/100 traps in September; as for habitats, rural natural villages had the highest rodent density of 1.28 rodents/100 traps, and there was a statistical difference in the seasonal variation of rodent density between different habitats ( χ ²=25.986, P<0.05); the dominant species was Rattus norvegicus, accounting for 77.69% of the total rodents captured. The density of mosquitoes was 45.67 mosquitoes/lamp·night and reached the peak of 112.20 mosquitoes/lamp·night in late July; as for habitats, livestock shed had the highest mosquito density of 160.07 mosquitoes/lamp·night, and there was a statistical difference in the seasonal variation of mosquito density between different habitats ( χ ²=33.115, P<0.05); the dominant species was Culex pipiens pallens, accounting for 27.99%. The density of flies was 6.97 flies/cage·hour and reached the peak of 11.56 flies/cage·hour in July; as for habitats, farmers’ market had the highest fly density of 11.12 flies/cage·hour, and there was a significant difference in the seasonal variation of fly density between different habitats ( χ ²=12.783, P<0.05); the dominant species was Lucilia sericata with a composition ratio of 44.77%. Cockroaches had a density of 0.62 cockroaches/paper and an infestation rate of 7.45%, and the density and infestation rate of cockroaches reached the peaked in September; serious infestation and a high density of cockroaches were observed in the key places such as farmer’ market and supermarket, and there was a statistical difference in the seasonal variation of cockroach density between different habitats ( χ ²=26.104, P<0.05); the absolute dominant species was Blattella germanica, accounting for 99.16%. Conclusion This study helps to gain a better understanding of the density, species composition, and dynamic variation of the main vectors in Liaoning province in 2020, and it is suggested that all cities adopt targeted and integrated control measures according to the results of vector surveillance in Liaoning province, so as to reduce the density of vectors and control related diseases.

Objective To establish a duplex droplet digital polymerase chain reaction (ddPCR) detection method for Japanese encephalitis virus (JEV) and West Nile virus (WNV). Methods Based on the designed primers and probes of JEV and WNV, a duplex ddPCR detection system for JEV and WNV was established. Its sensitivity, specificity, and repeatability were explored. The sensitivity was compared with the number of cycles required for the fluorescent signal to cross the threshold in each reaction tube of dual quantitative PCR. Results The detection sensitivity of the duplex ddPCR detection system could reach 10 ² copies/μl for both JEV and WNV, with good specificity and repeatability. No cross-reactivity was observed with the Dengue virus, Chikungunya virus, Zika virus, Tick-borne encephalitis virus, and human genome. Conclusion The established duplex ddPCR method shows high sensitivity and specificity for JEV and WNV detection, which provides a solution for detection for the two viruses in different scenarios.

Objective To investigate the role of blood-eating insects in the family Tabanidae in the spread of African swine fever virus (ASFV) in the Dabie Mountain region of Jinzhai county, Anhui province, China, and to provide evidence for the prevention and control of Africian swine fever in the region. Methods The insect trap method was used to collect wild horsefly in the Dabie Mountain region of Jinzhai county, Anhui province in September 2019. The collected horseflies were observed with a stereo microscope to preliminarily identify their species based on their morphological characteristics. The collected horseflies were separately ground and DNA was extracted using a tissue nucleic acid extraction kit and a virus nucleic acid extraction kit. Cytochrome c oxidase subunit Ⅰ (COⅠ) gene amplification and sequencing were performed on the tissue genome to identify the species of the horseflies. With the ASFV p72 gene primers published by World Organisation for Animal Health, the ASFV nucleic acid was amplified by PCR, followed by sequencing to detect the DNA of ASFV in the horsefly samples. Results A total of 24 horseflies were collected from three different locations. Through morphological observations and COⅠgene amplification and sequencing, the horseflies were identified as Tabanus hypomacros. Amplification with the ASFV p72 gene primers was positive for part of viral nucleic acid extraction samples, with an overall positive detection rate of ASFV of 45.83%. The product of the positive amplification with ASFV p72 primers was sequenced to be a 278 nt sequence. The phylogenetic analysis showed that the ASFV in the horsefly specimens and the epidemic ASFV strains in China were in the same evolutionary branch. Conclusion ASFV is found in wild horseflies in the Dabie Mountain region of Jinzhai county, Anhui province, and is highly homologous to the epidemic ASFV strains in China, indicating that T. hypomacros can be a potential mechanical transmission vector of ASFV.

Objective To investigate the epidemiological characteristics of transborder imported dengue fever cases in Yunnan province, China, and to provide guidance for the prevention and control of transborder imported dengue fever cases in Yunnan province. Methods Data of imported dengue fever cases in Yunnan province were obtained from the Infectious Disease Report Information Management System of China Information System for Disease Control and Prevention; Excel 2016 software was used for data collation and plotting; SPSS 19.0 software was used for statistical analysis and processing of the data; ArcGIS 10.5 software was used to plot the geographical distribution of imported dengue fever cases. Results From 2005 to 2019, there were 4 660 transborder imported dengue fever cases in Yunnan province, of which Southeast Asia cases accounted for 98.99% (4 613/4 660) and Myanmar’s cases accounted for 86.06% (3 970/4 613) of the total number of imported cases from Southeast Asia. Among the imported cases from Myanmar, the number of dengue fever cases imported into Dehong Dai and Jingpo Autonomous Prefecture accounted for 62.04% (2 463/3 970), and the cases imported in October as the peak month accounted for 35.49% (1 409/3 970). Among the imported cases from Myanmar, there were slightly more males than females, with a male-to-female sex ratio of 1.19:1; 21-30-year-old cases had the largest proportion among all age groups, accounting for 27.71% (1 100/3 970); farmers and business service providers were the main occupations, accounting for 42.95% (1 705/3 970) and 21.49% (853/3 970), respectively. Conclusion The risk of imported dengue fever in the border areas of Yunnan province is relatively high. It is recommended to reinforce joint prevention and control, strengthen the education on prevention and control of dengue fever for key groups of local residents and enhance the surveillance of imported dengue fever cases as well as the surveillance and control of Aedes vectors in key areas.

Objective To investigate the resistance of Musca domestica populations to commonly used insecticides in different regions of Zhejiang province, China, in 2021, and to provide a scientific basis for rational insecticide use of fly control. Methods Different field populations of M. domestica were collected from 12 monitoring sites in Hangzhou, Ningbo, Wenzhou, Shaoxing, Huzhou, Jiaxing, Jinhua, Quzhou, Taizhou, Lishui, Zhoushan, and Yiwu, Zhejiang province from April to November 2021. The topical application method was used to determine the resistance of M. domestica to seven commonly used insecticides of pyrethroids, organophosphorus and carbamates. Results The resistance ratios of M. domestica populations to beta-cypermethrin, deltamethrin, permethrin, beta-cyfluthrin, dichlorvos, chlorpyrifos, and propoxur were 0.83-255.00, 4.44-158.78, 6.11-64.81, 1.76-53.57, 2.45-130.11, 3.37-10.39, and 2.52-1 149.63 in 11 prefecture-level cities and Yiwu, Zhejiang province. Conclusion Some field populations of M. domestica in different regions of Zhejiang province have developed varying degrees of resistance to many of the seven commonly used insecticides. In the future fly control, measures should be taken to standardize the use of chemical insecticides based on the results of resistance monitoring in order to effectively reduce the density of flies and delay the development of resistance.

Objective To investigate the resistance level of Aedes albopictus against some commonly used insecticides in dengue endemic provinces of China, and to provide guidance for the proper usage of insecticides and epidemic prevention and control. Methods Excel 2016 software was used to collect and sum up the bioassay data of Ae. albopictus resistance to commonly used insecticides from 80 surveillance sites in 13 provinces in China. The WHO tube method was used to monitor the resistance of adult mosquitoes against 9 insecticides, and larval dip method was used to monitor the resistance of larvae mosquitoes against 3 insecticides. According to the Implementation Plan for National Vector Surveillance (2016), the resistance level was statistically analyzed and mapped using ArcGIS 10.3 software. Results The resistance of Ae. albopictus was monitored at 80 surveillance sites in China in 2020. For pyrethroid insecticides, Ae. albopictus adults developed resistance to deltamethrin, permethrin, beta-cypermethrin and beta-cyhalothrin at 83.08% (54/65), 77.97% (46/59), 87.30% (55/63),and 79.31% (46/58) of the surveillance sites, respectively. For carbamate insecticides, Ae. albopictus adults developed resistance to propoxur in 1.49% (1/67) sites, while none of the 61 sites showed resistance to bendiocarb. For organophosphorus insecticides, the Ae. albopictus adults at the 6.45% (4/62) surveillance sites developed resistance to malathion, while the 52 and 59 sites did not develop resistance to fenitrothion and chlorpyrifos. Ae. albopictus larvae at 93.48% (43/46), 28.30% (15/53), and 25.45% (14/55) of the sites showed medium or high resistance to pyriproxyfen, propoxur and temephos, respectively. Conclusion The resistance level of adult Ae. albopictus to pyrethroid insecticides and larva to pyriproxyfen were serious in dengue endemic and risk areas in China. However, both adult and larva were more susceptible to carbamate and organophosphorus insecticides at most of surveillance sites. Local authorities and program managers should adjust their insecticide use planning for Aedes mosquito control and dengue prevention and control according to the current insecticide resistance status.

Objective To analyze the results of tick ecological surveillance in Zhejiang province, China, 2017-2020, to understand species composition, density and seasonal fluctuation of ticks in Zhejiang province, and to provide a basis for the development of control measures. Methods Twelve surveillance sites for ticks were set up in Zhejiang province. Parasitic ticks were monitored by tick inspection on the body surface of animal and the questing ticks were monitored using drag-flag method. Ticks collected from the same sampling sites or animals were numbered uniformly or placed in the same tube and brought back to the laboratory for classification, identification, and counting. The monitoring data were processed and analyzed using Excel 2010 software. Results The parasitic tick index was 2.25 and the questing tick density was 0.48 ticks/flag·100 m in Zhejiang province, 2017-2020. Haemaphysalis longicornis was the dominant parasitic and questing tick. Among host animals, sheep had the highest tick index (4.29), followed by cattle (1.33). The dominant tick species were H. longicornis on sheep, Rhipicephalus microplus on cattle, H. longicornis on rural dogs, and R. sanguineus on urban dogs. The questing tick density was 0.94 ticks/flag·100 m in rural environment and 0.04 ticks/flag·100 m in scenic area. The tick density in Zhejiang province showed no obvious seasonal fluctuation. Conclusion In 2017-2020, the dominant tick species in Zhejiang province was H. longicornis. The dominant parasitic tick species varied across host animals, and sheep had the highest tick infestation rate. The questing tick density in rural environment was significantly higher than that in scenic area. The results can provide a reference for the public health institutions of Zhejiang province to formulate targeted tick and tick control measures.