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.

Objective To investigate the application effect of gridding management in the prevention and control of dengue fever in Jinghong, Yunnan province, China, and to provide a scientific basis for developing effective prevention and control strategies for dengue fever. Methods Based on the gridding management system of dengue fever prevention and control in Jinghong in 2019, epidemiological description and the geographic information system were used to analyze and evaluate the effectiveness of gridding management in the prevention and control of dengue fever in Jinghong in 2019. Results In 2019, 28 dengue fever grid points were divided in the urban area of Jinghong city. Imported cases occurred in June, the outbreak of dengue fever was observed in July, and the cases of dengue fever reached the peak in September (1 775 cases). For the 28 grid points in Jinghong from June to November, the monthly mean Breteau index (BI) was 11.18, 18.42, 14.62, 14.02, 5.81, and 2.09, respectively, the rate of reaching the standard of BI was 52.56%, 44.76%, 51.66%, 46.57%, 74.01%, and 91.71%, respectively, and the number of dengue cases were 8, 47, 540, 1 775, 473, and 72, respectively. Conclusion Gridding management can effectively prevent and control dengue fever by improving the rate of reaching the standard of BI in the urban area of Jinghong. It is suggested that the local government should further develop the grid management of dengue fever.

Objective To investigate the current status of residents' awareness of dengue in Jinghong, Xishuangbanna Dai autonomous prefecture (Xishuangbanna prefecture), Yunnan province, China, and to provide a scientific basis for the establishment of accurate response mechanism and the sustainable control of dengue. Methods A representative grid was selected randomly from the grids with dengue prevention and control during the period of dengue outbreak in Jinghong in 2019. A questionnaire survey was conducted among the residents in the grid in a one-to-one question- and-answer manner. SPSS 20.0 statistical software was adopted for the statistical analysis. Results A total of 249 valid questionnaires were collected. The chi-square analysis revealed that urban residents paid more attention to dengue-related knowledge than rural residents ( χ ²=12.444, P=0.040). The education system staff and the highly educated ones paid more attention to the knowledge of mosquito control. Residents with different occupations, monthly average income levels, and levels of education chose different ways of seeking medical treatment if they were inadvertently infected with dengue. The highly educated ones, those high-income earners, and the education system staff were more inclined to go to the grade A tertiary hospitals. Urban residents held the view that there were more dengue infections around themselves than around rural residents. The highly educated population had a higher proportion of people who thought they had enough knowledge of dengue prevention and control than the less educated population. The results of unconditional logistic regression analysis demonstrated that residents with different ages, levels of education, and current places of residence showed different abilities to use new media to acquire knowledge about dengue prevention and control. Conclusion In Jinghong, Xishuangbanna prefecture, the elderly, the rural residents, the less educated people, and the low-income earners had a relatively low level of awareness of dengue. It is suggested that in future, the above-mentioned populations should be focused on in the establishment of local accurate response mechanism and the scientific prevention and control of dengue.

Objective To investigate dengue fever-related knowledge level and preventive behaviors and their influencing factors in the Dai people in China-Myanmar border areas, and to provide a scientific basis for community-based dengue fever prevention and control in the border areas. Methods From December 2017 to April 2018, dengue fever-related knowledge level and preventive behaviors of the Dai people and the influencing factors were investigated using sampling questionnaire survey (household survey of householders) combined with in-depth interview of key opinion leaders (KOLs) and participatory observation in three types of communities (classified according to the incidence of dengue fever in 2017, i.e., high, medium, and low or none) in Xishuangbanna (XSBN), Yunnan province, China and Shan State Special Region 4 (SR4), Myanmar. The awareness rates were compared using chi-square test, and the influencing factors were analyzed by multivariate logistic regression. Results A total of 259 and 261 questionnaires were completed in XSBN and SR4 of Myanmar, respectively. Eighteen KOLs were interviewed in depth. In XSBN, the proportion of householders who knew that spotted mosquitoes or Aedes mosquitoes are vectors for dengue fever and the proportion of householders who knew that water containers are breeding sites of Aedes mosquitoes and their larvae were 76.08% (95% CI:70.44%-81.23%) and 89.07% (95% CI:84.53%-92.70%), respectively; the proportion of households which were reported to have a habit of turning over pots was 94.64%(95% CI:91.20%-97.01%). In SR4 of Myanmar, the above three proportions were 14.29%(95% CI:10.19%-19.10%), 24.32%(95% CI:19.22%-30.02%) and 72.76%(95% CI:64.44%-79.83%), respectively. The dengue fever-related knowledge level and preventive behavior performance rate of the Dai people were significantly higher in XSBN than in SR4 of Myanmar ( χ ²=41.004, P<0.001). The results of a logistic regression analysis showed that there were a higher dengue fever vector control performance rate in communities historically struck by dengue fever ( OR=23.90, 95% CI:3.07-185.82) and a lower vector control performance rate in households taking agriculture as their main economic source ( OR=0.14, 95% CI:0.03-0.63) in XSBN. There was a lower vector control performance rate of households in communities historically struck by dengue fever in SR4 of Myanmar ( OR=0.08, 95% CI:0.02-0.36). Age, dengue fever-related knowledge level, and awareness of the disease of householders may also influence preventive behaviors against dengue fever in SR4 ( all, P<0.05). Conclusion The Dai people in XSBN have a higher knowledge level of dengue fever, but their preventive behaviors need to be maintained by strengthened management. The preventive behaviors of the inhabitants in SR4 of Myanmar need to be boosted by further communication for behavioral change in addition to reinforced organizational safeguard.

Objective To investigate the resistance level of Aedes aegypti to 11 insecticides in the key areas of dengue fever in Yunnan province, China. Methods From August 2017 to September 2017, the pupae or larvae of Ae. aegypti were collected in Jinghong city and Mengding town, Gengma Dai and Wa Autonomous County, and then they were bred to the first generation (F1) in the laboratory. The resistance of the first generation to 11 insecticides was determined by the filter paper contact method. Results The 24 h corrected mortality rates of adult Ae. aegypti in Jinghong city to permethrin, λ-cyhalothrin, beta-cypermethrin, deltamethrin, α-cypermethrin, malathion, fenitrothion, bendiocarb, propoxur, fipronil, and DDT were 0.92%, 0, 3.19%, 91.40%, 20.43%, 85.86%, 100%, 97.71%, 96.67%, 99.41%, and 1.96%, respectively, and KT ₅₀ was >60, >60, 53.83, 45.39, 48.25, >60, >60, 36.34, 32.13, >60 min, and not calculable, respectively. The 24 h mortality rates of adult Ae. aegypti in Mengding town to the above mentioned insecticides were 1.43%, 3.01%, 11.35%, 60.27%, 5.96%, 100%, 100%, 100%, 95.68%, 95.95%, and 0.74%, respectively, and the corresponding KT ₅₀ was >60, >60, 26.48, 16.35, 22.67, >60, >60, 35.03, 40.17, >60 min, and not calculable, respectively. Conclusion Aedes aegypti in Jinghong city and Mengding town have developed different degrees of resistance to pyrethroids and DDT insecticides, but still present high sensitivity to malathion, fenitrothion, propoxur, bendiocarb and fipronil. Measures should be carried out accordingly to limit or stop the use of insecticides to which Ae. aegypti has already developed resistance.

Objective To understand the distribution and seasonal variations of Aedes aegypti in Yunnan, and to provide scientific evidence for the prevention and control of dengue fever, Zika and other diseases. Methods Collect data on dengue vector surveillance in Yunnan province from January 2016 to August 2017 and use the Excel software to carry out statistical analysis on the distribution of Ae. aegypti. Results Among the 22 dengue vector monitoring counties in Yunnan province, Ae. aegypti distributed in 8 counties i. e. Jinghong, Mengla, Menghai, Yingjiang, Gengma, Longchuan,Ruili and Cangyuan. In total, 796 monitorings were conducted in 8 border counties. Among 40 159 households, 1 677 had Ae. aegypti. Of the 66 192 containers, 2 211 had Ae. aegypti. The overall Breteau index(BI) was 5.51, the overall container index was 3.34%, the overall house index was 4.18. BI in Gengma was up to 10.80, while the lowest for Longchuan was 0.34. Aedes aegypti larval density peak occurred from May to July, its highest peaks were in June and July. The larval breeding containers were mainly water buckets, tires and discarded bottles. The most Ae. aegypti-breeding pools or water tanks or vases were found in Jinghong. The most breeding was noted in the tires, buckets and discarded bottles in the city of Ruili. The seasonal distribution and breeding habitats of Ae. aegypti larvae in eight counties were slightly different. Conclusion Aedes aegypti in Lincang have spread from Mengding to Mangka in the mid-levels, it would go up the hill to the mainland in Gengma county in the hilly area and in the Cangyuan county. The spreading of Ae. aegypti will have a profound effect on the prevention and control of dengue fever in Yunnan province. The breeding habitats and seasonal distribution of Ae. aegypti vary in different areas, and the prevention and control measures should be based on the actual situations.

Objective To investigate the distribution, seasonal fluctuation and the breeding environment of the dengue vector at the border areas of Yunnan province, and for providing the scientific basis for controlling measures of the dengue vector. Methods Collecting larvae at the habitat of 17 border cities in Yunnan province in 2016. Recording the breeding containers and identifying the fourth instar larvae at the laboratory. Calculating the Breteau index(BI), container index (CI), and house index(HI) of Aedes. Entering CI of the temporary water container and the permanent water container from 17 monitoring cities by SPSS 17.0 software. Compare t test of the two independent samples. Results In August 2016, it came out the highest results of the BI, CI, and HI which was 9.45, 4.15%, and 6.65% respectively. There was no statistical significant difference between the CI of the permanent water and the temporary water( t=-1.391, P=0.174). Aedes albopictus were distributed throughout the 17 border cities. There were Ae. aegypti populations in Gengma, Jinghong, Longchuan, Mengla, Ruili, Yingjiang, and Menghai county. Conclusion It still exists the risk of outbreak of the dengue fever in border areas of Yunnan province. Thus monitoring and controlling mosquito should be strengthened.

Objective To investigate the resistance of Aedes aegypti and Ae. albopictus to insecticides in Ruili city, Yunnan province, to provide the basis for integrated control of dengue vector. Methods Larvae of Ae. aegypti and Ae. albopictus were collected in Ruili city and Jiegao port and reared in laboratory to get F1 generation, to test their susceptibility to different kinds of insecticides by bioassays. The resistance level was decided by adjusted mortality. Results The 24 h mortality rate of adult Ae. aegypti in Ruili city to 0.25% permethrin, 0.03% λ-cyhalothrin, 8.00% α-cypermethrin, 0.80%malathion, 0.25% fenitrothion, 0.10% propoxur, and 4.00% DDT were 1.40% (resistant), 20.12% (resistant), 80.31% (suspicious resistant), 100% (susceptible),100% (susceptible), 100% (susceptible) and 14.93% (resistant)respectively. The 24 h mortality rate of adult Ae. aegypti in Jiegao port to above insecticides were 0.55% (resistant), 2.13% (resistant), 62.35% (resistant), 100% (susceptible), 100% (susceptible), 100% (susceptible) and 0 (resistant) respectively. In addition, the 24 h mortality of adult Ae. albopictus in Ruili city to 0.75% permethrin, 1.80% λ-cyhalothrin, 8.00% α-cypermethrin, 0.10% deltamethrin, 3.00% beta-cypermethrin, 0.44% malathion, 0.18% fenitrothion and 0.06% propoxur were 8.11% (resistant), 83.85% (suspicious resistant), 75.18% (resistant), 4.97% (resistant), 89.13% (suspicious resistant), 99.23% (susceptible), 100% (susceptible) and 100% (susceptible) respectively. Conclusion Aedes aegypti and Ae. albopictus in Ruili city have developed different levels resistance to pyrethroid insecticides, but present high susceptible to malathion, fenitrothion and propoxur.

Objective To study the characteristics of indoor mosquitoes, community composition, diversity, and seasonality in the south of Yunnan province, and to prevent local arbovirus infectious diseases. Methods In a village of Dai in Menghai county of Xishuangbanna prefecture in the north of Yunnan province, mosquitoes were captured by overnight trapping with ovitrap light and counted by species from June to October in 2014. Results Total of 15 391 mosquitoes were captured and were classified into 16 species of 5 genus in 3 subfamilies. The predominant species were Culex tritaeniorhynchus and Anopheles sinensis, the predominant index of them were 69.62 and 49.39(D>40). The sub-predominant species were An. argyropus, Cx. pseudovishnui, Cx. fatigans, An. peditaeniatus and An. minimus, the predominant index were 33.71, 31.79, 30.11, 16.88, and 16.48, respectively(D>10). Shannon-Wiener diversity index, Simpson dominance index and Pielo evenness index were 1.47, 0.29, and 0.53, respectively. Statistically analysis found that Cx. tritaeniorhynchus and An. sinensis, Cx. pseudovishnui and An. argyropus, An. peditaeniatus and An. minimus with better fitness. The peak months of indoor mosquitoes were July, August and September. Conclusion The indoor mosquitoes species in the south of Yunnan province were rich with complicated composition of community and approximately equal distribution of the predominant species. The species density of mosquitoes was high and the peak population density lasted for an extended period of time.

Objective To investigate the distribution of Aedes albopictus in the central city of Yuxi, providing scientific basis for prevention and control of dengue fever. Methods Mosquito larvae were captured indoor and outdoor water containers from north, south, west, east and central residential areas and special places in the central city; adult mosquito was collected by human landing collection and whole site at special places; and dengue virus was tested by specific nucleic acid detection for Ae. albopictus adult mosquitoes. Results Aedes albopictus was found in 3 villages at the north of the city and 1 residential area at the west of the city,the total container index(CI) was 0.37. In the east, south and center of the city, no Ae. albopictus was found. Total of 2 193 individuals of 7 species were collected from a waste tire processing factory and a salvage station in the north and west of the city, and Ae. albopictus accounted for 82.44%(1 808/2 193); the CI of larvae was 5.21, Breteau index reached up to 60.00 at waste tire processing factory in the north of the city. No dengue virus was detected in Ae. albopictus adult mosquitoes. Conclusion It was the first time found Ae. albopictus in the central city of Yuxi, and its density was high, it's hinted that there is a risk of dengue transmission and epidemic, and the attention should be paid by the relevant health departments.

Objective To understand the epidemiological characteristics of imported dengue cases in Yunnan during 2004-2014, and provide the scientific information for the effective strategies of dengue control and prevention. Methods The data of imported dengue cases were collected from China Information System for Diseases Control and Prevention during 2004 to 2014. A database was established to analyze the epidemiological characteristics with method of descriptive epidemiology; dengue serotype was detected by RT-PCR.Results From 2004 to 2014, a total of imported cases were 629 (629/2 192, 28.70%) in Yunnan; The imported cases of dengue were mainly reported in Dehong Prefecture (341 cases), Xishuangbanna Prefecture (159 cases) and Kunming city (108 cases); The cases were reported every month, but 85.37% (537/629) of the cases were imported between August and November. Male cases were much more than female, 419 and 210 cases respectively. The occupations of cases mainly were business service people (165 cases), farmers (134 cases) and students (72 cases). Most cases were imported from Myanmar (403 cases) and Laos (132 cases). Four (4) dengue serotypes were found from imported cases; of those DEN-3 was the major type in those from Laos, and DEN-1 in those from Myanmar. Conclusion The imported dengue cases have been on rise in Yunnan, and their major concerns are the border areas with Laos and Myanmar. The above results suggested that colloborative efforts from various agencies should be strengthened to monitor border imported dengue cases in case of dengue outbreak.

Objective To investigate the distribution of Aedes aegypti in border area in Yunnan province, providing scientific information for dengue control. Methods The distribution of Ae. aegypti was investigated by collecting mosquito larvae in different breeding sites and identifying fourth instar larvae; Aedes mosquito larva population density was investigated by Aedes Breteau index and container index. Results Total of 159 924 containers were investigated from 17 border counties, of those 2388 containers were positive; the Breteau index was 3.97, the container index was 1.46. There were 7489 individual larvae were collected, belonging to 3 species, of those 3303 individual larvae were Ae. aegypti, accounting for 44.10% of total collected larvae, 4119 individual larvae were Ae. albopictus, accounting for 55.00% of total collected larvae,12 individual larvae were Ae. annandalei, accounting for 0.90% of total collected larvae. Aedes mosquito larva population density peaks were occurred from May to October, its highest peaks were July and August. Ae. aegypti distributed in 7 counties i.e. Jinghong, Mengla, Menghai, Yingjiang, Longchuan, Ruili and Lushui. Conclusion Aedes aegypti distributed in 7 border counties of Yunnan province, and results suggested that its distribution was expanding to the neighbor areas, which warrants high attentions by disease control department.

Objective To investigate the species composition, ecological habitats and the natural infection of the dengue vectors in Menglian and Lancang counties bordered with Myanmar in Yunnan province, so as to provide evidence for the prevention and control of dengue fever. Methods Three villages in Menglian and Lancang counties were selected as surveillance sites. Adult mosquitoes were captured by human-landing catches and Aedes mosquito larvae were collected from various types of indoor and outdoor water containers in the three surveillance sites. Dengue virus in mosquitoes was detected by RT-PCR. Results A total of 3436 individual adult female mosquitoes of 22 species from 8 subgenus in 6 genus were collected from three sites in Menglian and Lancang counties from June to October, 2010. Aedes albopictus was the predominant species in three sites, accounting for 33.82% of all captured mosquitoes. No Ae. aegypti mosquitoes were found in these field sites. The average house index (HI), container index (CI), breteau index (BI), and thousand-person index of Ae. albopictus was 19.3, 5.84, 30.3, and 68.5 respectively. The dominant Ae. albopictus breeding environments were thick bamboo tubes, amphora, and used tires, accounting for 34.1%, 27.5% and 17.6%, of positive water containers, respectively. The average population density of Ae. albopictus adults was 8.98 per person per hour. The density peaked in July and August. Dengue virus was not identified by RT-PCR from 29 batches of Ae. albopictus. Conclusion Local dengue fever surveillance should be strengthened due to high vector density and wide distribution of Ae. albopictus in these areas.

【Abstract】 Objective To assess the situation and influence factors of insecticide treatment bed net(ITN) in Yunnan malaria endemic areas and provide the measures for generalization of ITN. Methods Cross survey was used among 47 counties of Yunnan malaria endemic areas by multi?stages sampling method. Results There were 8.68% of households with ITN. The use of bed net was influenced by economic status, gender, marriage, education level, attitude to the use of ITN, malaria transmission knowledge and preventive knowledge analyzed by logistic regression analysis. Conclusion It should pay more attention to the population from poor families, woman, single and illiterate during the promotion of ITN. The use of ITN could be promoted by the transmission of malaria transmission route and preventive measures.