Objective To investigate the infestation of bed bugs in China, and to provide a scientific basis for the risk assessment of bed bugs. Methods The bed bug surveillance data were collected from the national vector surveillance system in China, 2019. The status of bed bug infestation was compared between different provinces or habitats. Results In 2019, bed bug surveillance was carried out in 11 provinces, autonomous regions, or centrally administered municipalities via field investigation and telephone survey. A total of 1 351 units were investigated on site, of which 10 had bed bug, with a positive infestation rate of 0.74%. A total of 13 589 standard rooms were investigated, of which 31 (0.23%) had bed bugs. A total of 212 professional organizations (pest control companies and Centers for Disease Control and Prevention) were investigated by telephone, of which 11 (5.19%) had dealt with/consulted about bed bugs. Conclusion Bed bugs are widely distributed in China. The dormitories of construction sites, factories and schools are the environments where bed bugs occur more frequently.

Objective To investigate the density and seasonal fluctuation of ticks captured from human habitats and body surfaces of domestic animals in China, and to provide a basis for the risk assessment and scientific prevention and control of ticks and tick-borne diseases. Methods The surveillance data of ticks were collected from 45 surveillance sites in the national vector surveillance system in China, 2019. The dominant tick species was analyzed, and the density and seasonal fluctuation of ticks were compared between different habitats, hosts, and provinces. Results Among the ticks captured in 2019, Haemaphysalis was the most frequently captured genus; the number of times that parasitic and questing Haemaphysalis were captured accounted for 57.31% and 95.56% of the total catch, respectively. Among various host animals, sheep and cattle had higher tick indices (3.06 and 2.72, respectively), and ticks were also captured from dogs in rural and urban areas. The tick density in surroundings of villages (0.83 ticks/flag·100 m) was higher than that in scenic areas (0.32 ticks/flag·100 m). Among different months of surveillance, the seasonal fluctuation curves of parasitic tick index and questing tick density both showed two peaks; the index of parasitic ticks was high throughout the first half of the year and decreased after July, while the density of questing ticks peaked in June. Conclusion The tick surveillance results in 2019 show that Haemaphysalis is the most frequently captured genus. Sheep and cattle are dominant host animals of those captured ticks, while dogs, as domestic animals in close contact with human beings, should be paid attention to their tick infection. Surroundings of villages are the dominant habitat of ticks. The peak period of tick infestation is found in the first half of the year. Tick prevention and control should be carried out according to the above-mentioned key species, hosts, habitats, and time periods.

Objective To investigate the species, density, and spatio-temporal characteristics of cockroaches in human habitats and surroundings in China and the cockroach surveillance results based on the sticky trap method and visual observation, and to provide a scientific basis for cockroach prevention and control. Methods The cockroach surveillance data were collected from the national surveillance sites for vectors in China, 2019. Excel 2013 software was used to analyze the cockroach distribution characteristics of different species in different habitats, in different provinces, and at different times. Results In 2019, the surveillance results according to the sticky trap method showed that the sticky trapping rate was 5.45% and the infestation rate was 5.25%. Blattella germanica was the dominant species, accounting for 95.65% of the total catch, Periplaneta americana accounted for 2.42%, and the rest accounted for 1.93%. The surveillance results according to visual observation showed that the infestation rate of adult and nymph cockroaches was 3.63%, with 3.07% for B. germanica and 1.28% for P. americana. Farmers' markets and restaurants had high cockroach infestation rates. The cockroach infestation rate was high in South China and low in North China. The cockroach infestation rate measured by the sticky trap method was 1.45 times that by visual observation. Conclusion The national cockroach surveillance results in 2019 are conducive to the targeted cockroach control of key species in key habitats and areas, and at key times.

Objective To investigate the infestation of flies in residential areas in China, 2019, and to provide a reference for sustainable fly control. Methods The data of flies captured by the cage trapping method were collected from the national fly surveillance system in China, 2019, and the density and seasonal fluctuation of various fly species were compared between different habitats or provinces. Descriptive methods were used for statistical analysis. Results Among the fly species captured in 2019, Musca domestica (1.31 flies/cage), Lucilia sericata (0.83 flies/cage), species from Sarcophagidae (0.82 flies/cage), and Muscina stabulans (0.53 flies/cage) had the highest densities. Farmers' markets had the highest total fly density (5.78 flies/cage). The peak of total fly density occurred from June to August. Among the dominant fly species, M. domestica, L. sericata, and species from Sarcophagidae had similar seasonal fluctuation trends to that of the total fly density. Conclusion The fly surveillance data in 2019 suggest that M. domestica is still the dominant fly species in residential areas in China, with its peak period in June to August, and the most affected habitat is farmers' market.

Objective To analyze the Aedes surveillance data of 23 project provinces (autonomous regions and municipalities directly under the central government) in China, 2019, and to provide scientific evidence for the prevention and control of Aedes-borne diseases such as dengue. Methods The surveillance data of larval and adult Aedes mosquitoes from the surveillance sites of the 23 regions were analyzed using SPSS 18.0 software for a preliminary assessment of the risk of dengue transmission. Results In China, 2019, the mean Breteau index (BI) of Aedes mosquitoes was 3.56, and the mean mosquito ovitrap index (MOI) was 4.89. During the key months of the surveillance periods, the mean BI exceeded 10 in Zhejiang, Hainan, and Fujian provinces, and exceeded 5 in some surveillance points of Yunnan province. MOI was over 5 in Guangdong province and Guangxi Zhuang autonomous region during the key months of the surveillance periods. In Jiangxi, Anhui, Hunan, Henan, Sichuan, and Hubei provinces and Chongqing municipality, BI exceeded 5 in most months of the surveillance periods; MOI exceeded 5 in Hunan province from June to August and in Guizhou province from July to September, reaching the spreading risk of dengue. During the surveillance periods, BI exceeded 10 in Hebei province, and exceeded 5 in Shaanxi province from July to August and in Shandong province from August to September. The density of adult mosquitoes (net trap index) was more than 2 mosquitoes/net·hour in Fujian and Jiangsu provinces and Guangxi autonomous region during most months of the surveillance periods, in Hubei province from June to July, and in Shaanxi and Sichuan provinces during September. Conclusion In 2019, the densities of Aedes mosquitoes in most project provinces (autonomous regions and municipalities directly under the central government) of China exceed the transmission or outbreak threshold of dengue, indicating a high risk of local transmission and outbreak of dengue. Aedes surveillance and risk assessment should be strengthened continuously to ensure sustainable and precise control of Aedes mosquitoes and Aedes-borne diseases.

Objective To investigate the species, composition, density, distribution, and seasonal fluctuation of mosquitoes in China, 2019, and to provide a scientific basis for the prevention and control of mosquito-borne diseases. Methods The mosquito vector surveillance data of 88 surveillance sites in 30 provinces (autonomous regions and municipalities directly under the central government) of China in 2019 were collected. The light trapping and human-baited double net trapping methods were employed to monitor adult mosquitoes, and the Breteau index (BI), scoop capture, and route methods were adopted to monitor mosquito larvae. Adult mosquitoes were monitored twice a month, and mosquito larvae were monitored once a month. Excel 2013 software was used to analyze the mosquito vector surveillance data. Results The mean density of mosquitoes was 9.81 mosquitoes/lamp·night in China in 2019. Culex pipiens pallens/Cx. pipiens quinquefasciatus accounted for 57.73% of all captured mosquitoes, followed by Anopheles sinensis, Cx. tritaeniorhynchus, Aedes albopictus, and Ae. aegypti, which accounted for 20.27%, 12.22%, 2.29%, and 0.02%, respectively. The mosquito densities in Inner Mongolia, Hubei, Qinghai, Yunnan, and Hunan provinces were relatively high, being 22.60, 21.72, 17.14, 12.71, and 10.18 mosquitoes/lamp·night, respectively. The results of seasonal fluctuation by light trapping, human-baited double net trapping, scoop capture, and route methods all indicated that the peak period of mosquito activity was from June to September, and the highest peak was in July or August. The results of the Breteau index method indicated that the peak period of Aedes larvae was from April to September. The highest density of adult mosquitoes was in livestock sheds, being 36.29 mosquitoes/lamp·night, while the highest Breteau index of mosquito larvae was in waste tyre recycling factories, being 19.25 mosquitoes/lamp·night. Conclusion The dominant mosquito specie is Cx. pipiens/Cx. pipiens quinquefasciatus in China. It is recommended to implement prevention and control measures such as overwintering mosquito elimination and environment management from April each year in all provinces (autonomous regions and municipalities directly under the Central Government). In 2020, the main prevention and control measure is to pay more attention to timely cleaning of the mosquito breeding sites in residential areas, waste tyre recycling factories, and waste collection areas, so as to prevent and control mosquito-borne diseases from the origins.

Objective To analyze the national surveillance data of rodents in China, 2019, and to provide a basis for improving the quality of national rodent surveillance and formulating scientific control measures. Methods Eighty-nine prefecture-level cities were set up as surveillance sites in 30 provinces (autonomous regions and municipalities) and Xinjiang Production and Construction Corps. Rodents were captured once every two months in three habitats by night-trapping, night-cage and sticky board methods. The surveillance data of rodents were collected and sorted to analyze the species composition, distribution, and seasonal density fluctuation of rodents. Results A total of 4 317 rodents were captured in 2019, with a total density of 0.78 rodents/100 traps. Cage trapping had the highest density of captured rodents, followed by sticky trapping. Rattus norvegicus, Mus musculus, and R. tanezumi accounted for 47.30%, 27.89%, and 12.55% of the total rodents captured, respectively. The highest density of rodents was in rural residential areas among three habitats. The density of rodents first increased and then decreased all year round, and peaked in May. Conclusion The density, species composition, and seasonal fluctuation of rodents at national surveillance sites across China in 2019 show no significant differences from the results in 2005-2016. Local authorities should assess risks and formulate control strategies based on their surveillance results of previous years.