Objective To investigate mosquito in Yunnan province, China, as well as the population density, distribution, regional differences, and breeding habits of Aedes aegypti and Ae. albopictus in main urban areas. Methods Breteau index (BI) was used to investigate Aedes in the main urban areas of 129 counties, cities, and districts of Yunnan province, and all water containers in residential areas and special places (including park and green spaces in the urban area, recycling stations, tire collection stations, and hospitals) were checked. Water containers infested with larvae or pupae of Aedes vector were marked as positive, and the larvae in positive containers were collected and morphologically identified. Descriptive statistics was used to describe general information; the Chi-square test was used to investigate the difference in Aedes breeding sites between different areas and ecological environments, and the Chi-square test for trend was used to investigate the association between altitude and mosquito breeding density. Results Among the 129 counties, cities, and districts of Yunnan province, 71 (55.04%) were found to have Aedes vector, among which 68 (52.71%) were found to have Ae. albopictus alone and 3 (2.33%) were found to have both Ae. aegypti and Ae. albopictus. A total of 37 198 households were investigated, among which 1 068 households were positive for Aedes; a total of 167 206 water containers were found, among which 2 135 were positive, with a mean BI of 5.74, a house index of 2.87%, and a container index (CI) of 1.28%. Special places had significantly higher BI and CI than residential areas ( χ ²=4 509.220 and 128.591, both P<0.001). Tires were the most common type of water container and accounted for 44.84%, followed by other temporary containers (12.55%) and buckets (13.64%). Tires had the highest positive rate of 1.73%, followed by buckets (1.25%), other temporary containers (1.02%), waste bottles (0.95%), pool (0.59%), other permanent containers (0.56%), and vase (0.48%). In terms of water containers, Dehong Dai and Jingpo autonomous prefecture had the highest positive rate of 8.72% (583/6 689), followed by Honghe Hani and Yi autonomous prefecture (285/10 053, 2.83%), Xishuangbanna Dai autonomous prefecture (124/4 587, 2.70%), Wenshan Zhuang and Miao autonomous prefecture (271/10 662, 2.54%), and Pu'er city (308/12 691, 2.43%). Among the 2 135 positive containers, 1 849 (86.60%) were found to have Ae. albopictus, 251 (11.76%) were found to have Ae. aegypti, and 35 (1.64%) were found to have both Ae. albopictus and Ae. aegypti. The composition of Ae. aegypti was 79.66% in Mengla county, 67.03% in Ruili city, and 34.55% in Jinghong city, and there was a significant difference between them ( χ ²=28.194, P<0.001). The Chi-square test for trend showed a linear relationship between Aedes breeding rate and altitude ( χ ²=1 413.993, P<0.001), and Aedes breeding rate gradually decreased with the increase in altitude. Conclusion Ae. albopictus is widely distributed in Yunnan province and Ae. aegypti has become the dominant species in some areas. Special places have a higher breeding rate of Aedes than residential areas, and border regions tend to have a high mosquito density. The density of Aedes vector gradually decreases with the increase in altitude, and no Aedes breeding is observed in the places with an altitude above 2 000 m. Buckets, tires, and waste cans are the main contributors for Aedes breeding in residential areas, while tires and other waste containers are the main contributors for Aedes breeding in special places.

Both dengue fever (DF) and chikungunya fever (CHIKF) are important mosquito-borne viral diseases with global distribution, and these two diseases have relatively similar epidemiological and clinical features, with the main vectors of Aedes aegypti and Ae. albopictus. The local epidemic of DF occurred in China-Myanmar and China-Laos border areas of Yunnan province, China every year in 2013-2019, and it also occurred in China-Vietnam border area in 2019, while the local epidemic of CHIKF occurred in China-Myanmar border area for the first time in 2019. The imported cases of DF and CHIKF from Myanmar, Laos, Thailand, and/or Vietnam were the main cause of the local epidemic of these two diseases in Yunnan province. The special geographical location and ecological environment of Yunnan province are suitable for the breeding of the vector Aedes mosquitoes and the transmission of DF and CHIKF viruses. There are still high risks of re-epidemic or pandemic of DF and CHIKF in this region, with the possibility of endemic an severe cases of DF. At present, there is an urgent need to carry out in-depth research on the source of pathogens, the investigation of epidemic foci, clinical science, antibody level in population, and sustainable control of Aedes vectors, and meanwhile, control of cross-border spread, mosquito control, and joint prevention and control in China-Myanmar, China-Laos, and China-Vietnam border areas are the key prevention and control measures that need to be strengthened at present.

Global climate change may have an impact on disease vectors and vector-borne diseases and seriously threaten human health. Based on the current research findings,this article summarizes the impact of climate change on vectors and vector-borne diseases in China,and it is revealed that meteorological factors,including temperature,humidity,and precipitation,have a significant impact on the number,density,and distribution of disease vectors,as well as the spatial and temporal dynamics,epidemic frequency,and intensity of vector-borne diseases,with the coexistence of spatial-temporal heterogeneity. Climate change drives the epidemic areas of vector-borne diseases,such as dengue fever,to expand significantly to the west and the north and significantly increases the epidemic frequency and intensity of such diseases,and with continuous climate warming,there will be accelerately increases in epidemic intensity and risk population in the future. The research on adaptive strategies and measures has been carried out for the new challenges of vector-borne diseases caused by climate change and has provided a solution combining "top-down" administrative intervention and "bottom-up" community-integrated vector management. The WHO Global Vector Control Response 2017-2030 on a basis of sustainable vector management strategy puts forward specific objectives and requirements for the control of vector-borne diseases. Under the guidance of this strategy in the future,China needs to increase funding,pay attention to the cultivation of high-end talents, upgrade the surveillance system for vectors and vector-borne diseases in the context of climate change,and strengthen the research on risk assessment,prediction and early warning,control strategies,and intervention measures,so as to effectively cope with the new challenges of climate-sensitive vector-borne diseases,protect the vulnerable populations and public health security,and provide continuous,innovative,and precise strategies and measures.

Objective In order to overcome the disadvantages of traditional rodent monitoring methods which were labor-intensive, time-consuming, and of low accuracy, this article used a new portable and efficient electronic monitoring system to monitor the rodents in the target areas in real time. Methods In 2016-2017, the convolutional neural network recognition technology based on deep-learning artificial intelligence was used in laboratory to recognize rodent species and analyze and record their activities, habits, and numbers in the target areas. The system box was developed after continuous adjustment and improvement. In the field application test, a categorical data analysis was performed. Results The system had over 95.00% accuracy of rodent recognition, recording, and analysis and about 90.00% counting accuracy in laboratory, which could monitor the rodent activities within 50 m in diameter in real time with clear images. In the field application, the catching rate was significantly higher than that using sticky boards. Conclusion This portable monitoring system/box realizes the intelligent real-time rodent monitoring based on the local area network, which changes the traditional rodent monitoring methods and provides a digital and smart solution of rodent surveillance information.

Objective To investigate the epidemiological characteristics of dengue fever (DF) and the distribution characteristics of Aedes vector mosquitoes in Dehong Dai and Jingpo Autonomous Prefecture (Dehong prefecture) of Yunnan province, China in 2013-2019. Methods The descriptive epidemiological method was used to analyze the data of DF cases. Breteau index (BI) was used to monitor the density of Aedes larvae, and species identification was performed for the mosquitoes collected. Results A total of 4 974 confirmed DF cases were reported in Dehong prefecture in 2013-2019, with 2 504 (50.34%) imported cases and 2 470 (49.66%) indigenous cases. The mean annual incidence rate was 56.23/100 000, with the highest incidence rate of 112.61/100 000 in 2019. The prevalence of DF was observed in Ruili, Mangshi, Longchuan, Yingjiang, and Lianghe counties/cities of Dehong prefecture; the cases in Ruili accounted for 88.18% (4 386/4 974) of all cases in Dehong prefecture, with a mean annual incidence rate of 320.93/100 000 and an annual incidence rate as high as 661.45/100 000 in 2019; the cases in the other 4 counties/cities accounted for 11.82% (588/4 974). Imported cases from Myanmar were reported in each month, mainly from July to December, while indigenous cases only occurred from June to November, with a peak in September and October. The age of patients ranged from 5 months to 92 years, mainly 20-49 years, and the male/female ratio was 1.06:1. As for occupation, 41.86% were business service providers, 17.01% were engaged in housework or were unemployed, 11.58% were students, and 9.28% were farmers. Family clusters were observed in 403 households involving 992 cases in Ruili. As for mosquito density in Ruili in 2013-2019, BI was 10-45 from June to November and <5 in the other months. Among the 39 469 larvae collected in 2019, Ae. aegypti accounted for 47.80%, Ae. albopictus accounted for 29.25%, and other mosquito species accounted for 22.95%. Ae. aegypti was mainly distributed in Ruili city, Zhangfeng town of Longchuan county, Labang town of Yingjiang county, and Manghai and Zhefang towns of Mangshi city, and Ae. albopictus was widely distributed in Dehong prefecture. Conclusion Both imported and indigenous DF cases are reported in Dehong prefecture in 2013-2019, and imported cases from Myanmar are the main cause of local prevalence of DF in Dehong prefecture. The epidemic areas of DF in Dehong prefecture are consistent with the distribution of Ae. aegypti, and the seasonal distribution of DF cases is closely associated with the increase in mosquito density. Strengthening the surveillance and management of the cross-border transmission of DF along the Sino-Myanmar border and conducting regular mosquito control are the key measures to control DF in this region.

Objective To analyze the epizootic trend of animal plague in the natural plague foci of Hebei province, China, and to provide evidence for formulating the strategies for the prevention and control of plague in Hebei province. Methods The monitoring data of animal plague in the natural plague foci of Hebei province from 1950 to 2019 were analyzed using Excel 2007 and SPSS 19.0 softwares. The number of Yersinia pestis positive animals was described as constituent ratio. The distribution of different groups was compared by the χ ² test. The seasonal distribution of animal plague was analyzed by concentration degree. Results The median interval of plague epizootics in the natural plague foci of Hebei province was 9.5 years. The epizootics had certain seasonality ( M=0.387), with a high frequency during October to November and then during April to May. Kangbao pasture (constituent ratio 73.13%) and Zhaoyanghe town (constituent ratio 26.12%) were the main epizootic areas. Meriones unguiculatus (constituent ratio 87.31%) was the main animal involved in the epizootics. The main vectors were Nosopsyllus laeviceps kuzenkovi (constituent ratio 1.49%) and Citellophilus tesquorum mongolicus (constituent ratio 1.49%). Among positive rodents, 92.25% were naturally dead rodents. The number of Y. pestis strains isolated from M. unguiculatus was significantly different between five rounds of plague epizootics ( χ ²=20.026, P<0.001). The average density of M. unguiculatus was 1.98/hm ², the average flea index of body fleas was 1.12, and the average flea index of nest fleas was 3.19. Conclusion Plague epizootics in the natural plague foci of Hebei province show intermittent and relatively stable characteristics. In order to reduce the risk of animal plague, close attention should be paid to the density and parasitic flea index of M. unguiculatus, and measures should be taken timely to kill rodents and fleas in spring and autumn. At the same time, the searching for naturally dead rodents in historical epizootic areas should be strengthened to discover plague epizootics in time and prevent the spread of plague.

Objective To investigate the epidemiological characteristics and infection sources of human brucellosis in Qinghai province, China, 2017-2019, and to provide a scientific basis for the prevention and control of brucellosis. Methods The data of brucellosis cases in Qinghai province from 2017 to 2019 were collected, as reported by the China Information System for Disease Control and Prevention. The descriptive epidemiological method was used to analyze the epidemiological characteristics. The isolated bacteria were cultured and identified to analyze the etiological characteristics. Results From 2017 to 2019, a total of 301 brucellosis cases were reported in Qinghai province, with an incidence of 0.45/100 000 in 2017, 1.81/100 000 in 2018, and 2.72/100 000 in 2019, with a significant difference between different years (t=16.421, P<0.05). The 301 cases were distributed in 26 counties (cities, districts), among which the top three counties (cities, districts) were Menyuan county (137/301, 45.51%), Dulan county (30/301, 9.97%), and Haiyan county (25/301, 8.31%). The age of onset ranged from 14 to 78 years, and the ratio of males to females was 3.63:1. Among the 301 cases, the top three occupations were farmers (31.89%), herdsmen (25.58%), and animal epidemic prevention personnel (20.27%); the mode of infection included livestock fattening and selling (108/301, 35.88%), rearing (97/301, 32.23%), animal epidemic prevention (61/301, 20.27%), processing (26/301, 8.64%), and food-borne infection (9/301, 2.99%). From 2018 to 2019, 37 whole blood samples with positive Rose Bengal plate agglutination test, colloidal gold immunochromatographic assay, and serum agglutination test were cultured, and 8 suspected strains were obtained, with a culture rate of 21.62%. The 8 strains of Brucella were identified as B. melitensis (cluster Ⅲ). Conclusion Currently B. melitensis (cluster Ⅲ) is the main epidemic strain causing human brucellosis in Qinghai province. And the prevalence of brucellosis in Qinghai province is on the rise. It is suggested that relevant departments should strengthen the control of sources of infection and take health promotion and other prevention and control measures among the high-risk population to control the occurrence and epidemic of brucellosis.

Objective To investigate the mosquito species and the distribution of mosquito-borne viruses in some regions of Guizhou province, China, and to provide a basis for the prevention and control of mosquito-borne diseases in this area. Methods Mosquitoes collected with trapping lamps were identified, mosquito-borne viruses were identified by molecular biological methods, and a phylogenetic tree of virus strains was constructed using bioinformatics software. Results A total of 27 169 mosquitoes (9 species, 3 genera) were collected in Zhongchao town of Liping county and Yangchang town of Wudang district (Guiyang city) of Guizhou province in June 2019. The dominant species was Anopheles sinensis (13 712/27 169,50.47%), followed by Culex tritaeniorhynchus (12 444/27 169,45.80%) and other species (70/27 169,0.26%). A virus strain isolated from a mosquito sample (LK6110) from Zhongchao town was identified as Japanese encephalitis virus genotype Ⅲ (JEV Ⅲ). Conclusion In this investigation, Yangchang town was dominated by An. sinensis and Zhongchao town was dominated by Cx. tritaeniorhynchus, and JEV Ⅲ was isolated from Cx. tritaeniorhynchus in Zhongchao town.

Objective To analyze the epidemiological characteristics of Japanese encephalitis (JE) in eight provinces and municipalities of northern China (Gansu, Ningxia Hui Autonomous Region, Shaanxi, Shanxi, Hebei, Beijing, Tianjin, and Liaoning) from 2005 to 2019, to investigate the pattern of the development of JE, and to provide a scientific basis for effective prevention and control of JE. Methods A descriptive epidemiological analysis was performed for JE cases in the above eight northern provinces and municipalities from 2005 to 2019, which were collected through the China Information System for Disease Control and Prevention and JE Surveillance Information Reporting and Management System. Results From 2005 to 2019, the mean annual incidence rate of JE was 0.14/100 000 and there were 390 deaths, with a case fatality rate of 7.25%. The distribution of JE expanded from 157 counties/districts in 2005 to 254 counties/districts in 2018. The number of cases from August to September accounted for 81.26% of all cases, and August and September were the peak periods for the onset of JE. The proportion of patients aged 0-14 years decreased from 54.55% in 2005 to 3.96% in 2019, and the proportion of patients aged ≥ 15 years increased from 45.18% in 2005 to 96.03% in 2019 ( χ ² _trend=998.524, P<0.001). Farmers, preschool and scattered children, and students accounted for 58.76%, 14.81%, and 12.38%, respectively. The proportion of farmers increased from 37.19% in 2005 to 79.21% in 2019. Conclusion The distribution of JE has expanded in the eight provinces and municipalities of northern China, and age distribution tilts toward high age. As for occupational composition, there is an increase in the proportion of farmers.

Objective To investigate mosquito population variation in Jiangsu province, China from 2008 to 2018, and to provide a basis for mosquito control in Jiangsu province. Methods We collected adult mosquito surveillance data obtained using the lamp trapping method at provincial surveillance sites in Jiangsu from 2008 to 2018 to analyze mosquito population variation in urban and rural areas in Jiangsu. The pairwise Kruskal-Wallis test was used for statistical analysis. Results The mosquito density in urban areas, rural areas, and the whole province in Jiangsu from 2008 to 2018 was 7.53, 61.26, and 28.26 mosquitoes/light·night, respectively; in general, the annual mosquito density showed an increasing trend in urban areas, but a decreasing trend in rural areas and the whole province. In the three types of habitats in urban areas, i.e., residential areas, parks, and hospitals, parks were dominant habitats; in the two types of habitats in rural areas, i.e., civilian residences and livestock sheds, livestock sheds were dominant habitats, which were also absolutely dominant habitats among the five types of habitats mentioned above, with a mosquito density over seven times that in other four types of habitats. In the 11 years, the pooled mosquito density by month showed a single-peak variation in urban areas, rural areas, and the whole province, with a peak density in July (17.81, 235.23, and 101.95 mosquitoes/light·night, respectively, for the above three areas); in mosquito seasons, the mosquito density by month in rural areas was 1.50-13.20 times that in urban areas. The composition of mosquito populations in Jiangsu province was mainly Culex pipiens pallens, Cx. tritaeniorhynchus, Aedes albopictus, Anopheles sinensis, An. lesteri, and Armigeres subalbatus; Cx. pipiens pallens was the absolutely dominant species in urban areas; in rural areas and the whole province, the dominant species was Cx. tritaeniorhynchus in most of the 11 years and was Cx. pipiens pallens in the other few years. In most of the 11 years, the density of Cx. pipiens pallens in rural areas was about 2 times that in urban areas, with a significant difference between the two (χ²=15.783, P<0.01); in each of the 11 years, the density of Cx. tritaeniorhynchus in rural areas was over 10 times that in urban areas, with a significant difference between the two (χ²=15.783, P <0.01); the density of the two dominant species showed a single-peak seasonal variation, with a peak density in July. Except for the dominant species, the pooled density by month of other four species was higher in rural areas than in urban areas. Conclusion Remarkable achievements have been made in mosquito control in rural areas in Jiangsu province, while more efforts are needed in urban areas. The focus of mosquito control in rural areas should be livestock sheds and dominant mosquito species; effective surveillance of Ae. albopictus and Ar. subalbatus remains to be pushed forward. The pooled mosquito densities by year and month over the 11 years can provide a preliminary reference for the initiation of mosquito control in Jiangsu province.

Phototaxis, chromatics tropism, and chemotaxis are the main behavioral characteristics of disease vectors and play important roles in the life activities of vectors. At present, induced killing and repelling techniques based on tropism have been widely used in vector monitoring and control. With in-depth studies on tropism in recent years, various technologies are gradually improved and optimized and are developing along the direction of high efficiency, strong specificity, and environmental protection. This article reviews the data on the research and application of vector tropism published in the recent 20 years, summarizes the research advances in common tropisms of vectors and their application in the control of vectors such as mosquitoes, flies, rodents, and cockroaches, and points out current problems and shortcomings and the future prospects and directions of tropism research, in order to provide a reference for better application of vector tropism in prevention and control.

Objective To establish a RT-hemi-nested PCR assay for laboratory detection of mosquito-borne alphaviruses based on the universal primers of mosquito-borne alphaviruses. Methods Three universal primers of mosquito-borne alphaviruses were designed in the conserved regions based on the whole genome sequence of alphaviruses in GenBank. The RT-hemi-nested PCR assay was established using the cDNAs of Sindbis virus (SINV) and Chikungunya virus (CHIKV) as templates under optimized conditions; the sensitivity and specificity of this method were validated and mosquitoes collected in the field were tested. Results The sensitivity test results showed that the lowest detection limit of SINV and CHIKV was 3×10 ³ and 3×10 ⁴ copies/µl. The sensitivity test results showed that the RT-hemi-nested PCR was only able to amplify the alphavirus. The established method was used to detect mosquito specimens collected in the field. The results showed that mosquito-borne alphavirus was not detected in all samples . Conclusion The RT-hemi-nested PCR assay established in the study is highly specific and sensitive and can be used for epidemiological survey on alphavirus infection.

Objective To investigate the common species and density of mosquitoes and their seasonal variation at vector surveillance sites in Heilongjiang province, China, and to provide a basis for risk assessment of mosquito-borne diseases and scientific development of mosquito prevention and control measures. Methods Mosquito surveillance data from 2007 to 2017 were collected from vector surveillance sites in Heilongjiang province; the data were compared for the differences in mosquito density between various species and habitats as well as their seasonal variation; Microsoft Excel 2016 software was used for statistical analysis. Results From 2006 to 2017, the total mosquito density was 2.26 mosquitoes/lamp·hour at the vector surveillance sites in Heilongjiang province; the mosquito species composition was dominated by Anopheles sinensis, accounting for 40.15% of the mosquitoes captured; the density of An. sinensis was highest, up to 0.91 mosquitoes/lamp·hour; the highest density was in livestock sheds (up to 6.12 mosquitoes/lamp·hour), followed by rural households (2.70 mosquitoes/lamp·hour); the seasonal variation in mosquito density of different species and habitats showed a single-peak trend, with the highest density in July and August. Conclusion Except for the density in 2007 (which is relatively high), the density of mosquitoes at the vector surveillance sites in Heilongjiang province from 2008-2017 shows a small-amplitude wavy decline; An. sinensis is the dominant species; the density is highest in rural areas, which are the key areas for mosquito prevention and control; mosquito activity peaks in July and August, which are the key periods for prevention and control measures.

Objective To investigate the species distribution, species composition, blood-sucking rate, and light-trap index in the cattle pens in three northeastern provinces of China. Methods From 2010 to 2019, hematophagous midges were captured with light traps from cattle pens in 7 counties (cities) in three northeastern provinces of China. The Chi-square test was used to compare the blood-sucking rates. Results A total of 322 505 hematophagous midges were collected from 7 counties (cities) in northeast China, which belonged to 29 species from 2 genera, including 28 species of Culicoides and 1 species of Lasiohelea. Among them, Kuandian county had 19 species, Dongning city had 15 species, Xunke county had 15 species, Dunhua city had 8 species, Fuyuan county had 8 species, Qingyuan county had 6 species, and Ji'an city had 7 species. The dominant species were C. sinanoensis (38.42%) and C. punctatus (37.60%), and the species composition varied in different counties (cities). The overall blood-sucking rate of 9 main species in 4 counties (cities) was 54.63%. Specifically, C. orientalis had the highest blood-sucking rate (71.87%), and C. humeralis had the lowest (14.68%). The overall light-trap index in 5 counties (cities) was 4 788.98 midges/light·night. Specifically, Dunhua city had the highest light-trap index (9 499.94 midges/light·night), and Xunke county had the lowest (1 408.62 midges/light·night). The blood-sucking rate and light-trap index varied across different midge species and counties (cities). Conclusion There were 29 species from 2 genera of hematophagous midges in the cattle pens of 7 counties (cities) in three northeastern provinces of China. The dominant species were C. sinanoensis and C. punctatus. C. orientalis had the highest blood-sucking rate, and Dunhua city had the highest light-trap index.

Objective To analyze the weak links of vector prevention and control in the secret evaluation of healthy cities in China, and to propose the focus and direction of vector prevention and control in the establishment or consolidation of healthy cities. Methods The secret evaluation indicators for vector prevention and control in 35 national healthy cities (counties or districts) were retrospectively reviewed. With IBM SPSS 20.0 software, the correlation between the total score and the individual score of vector prevention and control was determined by Pearson correlation analysis. The scores of different cities were compared using the independent-samples t test. Results There was a positive correlation between the total score and the individual score of vector prevention and control ( r =0.812, P <0.001). No significant differences in the scores of vector prevention and control were found between prefecture-level cities and county-level cities ( t =0.375, P =0.710) and between established healthy cities and reexamined healthy cities ( t =1.506, P =0.141). Among the second-level indicators, two indicators of fly control and rodent control were where points were easy to lose. Among the third-level indicators, rodent bait station, anti-rodent facilities in key industries, facilities for fly control, fly breeding area control, adult fly density control, and mosquito breeding area control failed to meet the standard. Conclusion Vector prevention and control, where the management of vector breeding areas and the construction of anti-vector facilities are weak links, is closely related to other urban management work. Comprehensive mobilization, extensive publicity, health education, establishment of regulations, professional guidance, and improvement of facilities are the guarantee to consolidate the effects of vector control.