20 April 2021, Volume 32 Issue 2
    

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    Expert Forum
  • Advances in the research and application of disease vector tropism
    XIN Zheng, MA Hong-wei, WANG Dong, ZHANG Xiao
    Chines Journal of Vector Biology and Control. 2021, 32(2): 121-126. https://doi.org/10.11853/j.issn.1003.8280.2021.02.001
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    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.
    • Experimental Study
  • A study of spatial stability of Aedes albopictus in Shanghai, China
    ZHOU Yi-bin, ZHU Yi-yi, ZHU Jiang, LENG Pei-en, WU Huan-yu
    Chines Journal of Vector Biology and Control. 2021, 32(2): 127-131. https://doi.org/10.11853/j.issn.1003.8280.2021.02.002
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    Objective To study the spatial stability of vector abundance of Aedes albopictus in Shanghai, China, and to provide a basis for prevention and control of dengue fever. Methods From May to November 2019, sub-district/township-based surveillance of Ae. albopictus density was carried out in Shanghai using mosquito ovitraps. The global spatial autocorrelation Moran's I index was calculated to determine the spatial clustering pattern in the whole study area. Spearman's correlation coefficient was used to determine the correlation between the positive rates of mosquito ovitraps in administrative areas or sub-district/townships at different times. Kendall's coefficient of concordance (Kendall's W) was calculated to measure the agreement between rank orders of positive rates of mosquito ovitraps at different times. Results In 2019, the highest, lowest, and median mean positive rates of mosquito ovitraps per year were 8.70%, 1.88%, and 5.46%, respectively, for each administrative area in Shanghai, and were 30.21%, 0, and 5.51%, respectively, for each sub-district/township. Spatial analyses showed that the density of Ae. albopictus was higher in the west and north of the city. The Spearman's correlation coefficients on sub-district/township and administrative area scales were greater for 1 week before as compared with those for 3 weeks before and were greater for 3 weeks before as compared with those for 6 weeks before; the Spearman's correlation coefficients on an administrative area scale were greater than those on a sub-district/township scale. During the study period, the Kendall's W of positive rates of mosquito ovitraps was 0.627 in a sample unit of administrative areas (χ2=197.542, P<0.001), and was 0.436 in a sample unit of sub-districts/townships (χ2=1 802.154, P<0.001). Conclusion The spatial stability of positive rates of mosquito ovitraps on an administrative area scale is better than that on a sub-district/township scale. Therefore, attention should be paid to sub-districts/townships with abnormal density changes while the prevention and control measures are strengthened in administrative areas with a high density of Ae. albopictus.
  • Establishment and application of RT-hemi-nested PCR assay for detection of mosquito-borne alphaviruses
    XUE Zhi-jing, ZHAO Ning, WANG Jun, SONG Xiu-ping, MENG Feng-xia, LIANG Wen-qin, ZHOU Jing-zhu, WANG Dan, ZHANG Zhong, LIU Qi-yong
    Chines Journal of Vector Biology and Control. 2021, 32(2): 132-138. https://doi.org/10.11853/j.issn.1003.8280.2021.02.003
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    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 3×103 and 3×104 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.
  • Transovarial transmission of a new genotype Candidatus Rickettsia longicornii of spotted fever group Rickettsia in Haemaphysalis longicornis
    LI Ji-xu, PIAO Wen, JIN Guang-jun
    Chines Journal of Vector Biology and Control. 2021, 32(2): 139-143. https://doi.org/10.11853/j.issn.1003.8280.2021.02.004
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    Objective To investigate whether Haemaphysalis longicornis can transovarially transmit the spotted fever group Rickettsia (SFGR) new genotype Candidatus Rickettsia longicornii. Methods Feeding H. longicornis was collected from cattle body surfaces and induced to oviposit in the laboratory. The polymerase chain reaction was used to detect the nucleic acid of Candidatus R. longicornii in tick eggs. The gene sequences of Candidatus R. longicornii in the mothers and eggs of H. longicornis were amplified. An analysis was performed on the homology and phylogenetic relationship. Results A total of 55 feeding H. longicornis (adult female ticks) were collected, among which 21 (38.18%) were positive for Candidatus R. longicornii according to the nucleic acid test. About 2 500 H. longicornis eggs were collected and divided into 50 groups, of which 6 groups were positive for Candidatus R. longicornii. The minimum infection rate was 0.24% in tick eggs. The homology analysis showed that the gene sequences of Candidatus R. longicornii from H. longicornis mothers and eggs had more than 99.79% homology with that of the tick-derived ROK-HL727 strain first found in South Korea. The Candidatus R. longicornii gene sequence homology between H. longicornis mothers and eggs was over 99.69%; the gene sequences were in the same branch and had close phylogenetic relationships with that of the ROK-HL727 strain. Conclusion The infection rate of H. longicornis mothers with the SFGR Candidatus R. longicornii genotype is relatively high, and the genotype can be transovarially transmitted.
    • Vector Surveillance
  • Integrated mosquito prevention and control package and efficacy evaluation in the endemic area of Japanese encephalitis in Jingning county of Gansu province, China, 2019
    MENG Feng-xia, SUN Yang-xin, WU Zhao, WU Hai-xia, ZHAO Chun-chun, JIA Yu-xin, LI Zhi-ping, MAO Wen-xiu, LUN Xin-chang, ZHANG Peng-ju, YAN Jun, LYU Wen, QIU Liu-yu, LIU Qi-yong
    Chines Journal of Vector Biology and Control. 2021, 32(2): 144-149. https://doi.org/10.11853/j.issn.1003.8280.2021.02.005
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    Objective To implement sustainable vector control strategies and measures for Japanese encephalitis (JE) by carrying out integrated mosquito prevention and control (IMPC) in developing rural areas of Gansu province as a health, poverty alleviation, and public welfare activity in 2019, and to provide a IMPC package for mosquito control in high-prevalence areas of JE in China. Methods The activity was jointly proposed by professional institutes and social organizations, technically guided by disease control specialists, and implemented by several enterprises and voluntary teams engaged in pest control operation (PCO). Zhaoshi village in Bali town, Jingning county, Pingliang, Gansu province, with the highest incidence rate of JE in 2017, was selected, and integrated management strategies were carried out, including public education for villagers, thorough elimination of mosquito larvae breeding sites, and chemical control in key areas. During the activity, the lamp trapping method was used to monitor the change in mosquito density to evaluate the effect of integrated mosquito control. Results A total of 41 enterprises participated in the activity, and 19 technical specialists and 37 PCO volunteers formed the team of volunteers. Investigation before control showed that bonsai, aquatic plants, cisterns, tanks, and basins were the main containers for water accumulation, with a positive rate of water accumulation of 34.32% and a 100-household index of 85.33. Main mosquito breeding sites in the external environment within and around the village included pipe wells, sewer water, open channels, sewage lagoons, unused bowls/bottles/tanks/cans, and waste tires, with a positive rate of 17.31%. The results of monitoring before control showed that the density of adult mosquitoes was 50.33 mosquitoes/trap/night, and Culex tritaeniorhynchus was the dominant species accounting for 80.13%, followed by Cx. pipiens pallens accounting for 12.91% and Anopheles sinensis accounting for 5.96%. After the first time of prevention and control, the density of adult mosquitoes was reduced to 11.60 mosquitoes/trap/night, with Cx. pipiens pallens accounting for 43.11%, Cx. tritaeniorhynchus accounting for 17.24%, An. sinensis accounting for 5.17%, and other mosquito species accounting for 34.48%, and the mean reduction rate of mosquito density was 76.95%. After the second time of prevention and control, the total mosquito density was reduced to 6.67 mosquitoes/trap/night, with An. sinensis accounting for 42.50%, Cx. pipiens pallens accounting for 17.50%, Cx. tritaeniorhynchus accounting for 15.00%, and other mosquito species accounting for 25.00%; the mean reduction rate of mosquito density was 86.75%, and the reduction rate of peasant households reached 100%. With the implementation of integrated mosquito prevention and control measures, the composition ratio of Cx. tritaeniorhynchus decreased from 80.13% to 15.00%. There was a significant reduction in mosquito larvae breeding sites after on-site public education and treatment, with a reduction rate of 93.24% based on container index. Conclusion The sustainable mosquito control mode of monitoring, control, and evaluation has a good effect in spreading the knowledge of mosquito prevention and control and reducing mosquito density and can be widely used in the high-prevalence areas of JE in China. Such measures should be taken in accordance with local conditions to achieve a better effect.
  • An investigation of the distribution of dengue vector Aedes in the main urban areas of 129 counties (cities, districts) of Yunnan province, China
    ZHOU Ke-mei, YANG Ming-dong, LAN Xue-mei, ZHENG Yu-ting, TANG Ye-rong, WU Chao, JIANG Jin-yong
    Chines Journal of Vector Biology and Control. 2021, 32(2): 150-157. https://doi.org/10.11853/j.issn.1003.8280.2021.02.006
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    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 (χ2=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 (χ2=28.194, P<0.001). The Chi-square test for trend showed a linear relationship between Aedes breeding rate and altitude (χ2=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.
  • A study of the density of plague host Spermophilus dauricus by concentration method
    LIU Guan-chun, KANG Dong-mei, YAN Dong, LAN Xiao-yu, HOU Zhi-lin, CHEN Yong-ming, REN Xing-yu, SONG Ming
    Chines Journal of Vector Biology and Control. 2021, 32(2): 158-160. https://doi.org/10.11853/j.issn.1003.8280.2021.02.007
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    Objective To provide a scientific statistical method for accurate determination of the seasonal density of plague host animals. Methods The data of Spermophilus dauricus were collected using Excel 2013 software from a natural plague focus monitoring site in Kangbao pasture in Hebei province, China from April to October in 2015-2019. The seasonal density of S. dauricus was analyzed by the concentration method. Results From 2015 to 2019, a total of 240 S. dauricus individuals were captured in an area of 490 hm2, and the mean annual density in Kangbao pasture was 0.49 inds/hm2. The highest density was 0.66 inds/hm2 in summer, followed by 0.37 inds/hm2 in Autumn and 0.18 inds/hm2 in winter. The highest density was recorded in April 2016 (2.53 inds/hm2), followed by 1.94 inds/hm2 in April 2015 and 1.07 inds/hm2 in July 2018. Analysis with the concentration method showed M=0.330 5, suggesting that the density of S.dauricus varied across seasons. Conclusion The concentration method can accurately determine the seasonal density of S. dauricus as a plague host, and the highest density is found in summer, followed by autumn.
  • An investigation of the species composition and distribution of rodents and their parasitic fleas in the Winter Olympic Games zone and surrounding areas in Zhangjiakou, Hebei province, China
    YAN Dong, CHEN Yong-ming, SUN Fei, MA Yong, ZHOU Song, LIU Guan-chun, YANG Shun-lin, GUO Chao, DAI Hong, ZHANG Jin-yi, ZHANG Xiao-lei, WEN Lin, WANG Xiao-yan, DU Guo-yi, SHI Xian-ming
    Chines Journal of Vector Biology and Control. 2021, 32(2): 161-164. https://doi.org/10.11853/j.issn.1003.8280.2021.02.008
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    Objective To investigate the species composition, quantitative distribution, and seasonal variation of rodents and their parasitic fleas in the Zhangjiakou 2022 Winter Olympic Games zone (hereinafter referred to as the Zhangjiakou competition zone) and the surrounding areas in Hebei province, China, and to provide basic data for the prediction and emergency treatment of vector-borne diseases during the Winter Olympic Games. Methods From September 2018 to September 2019, the five-meter traping method and the quadrat method were used to investigate the species composition and density of rodents in Chongli district and the area around the Zhangjiakou competition zone, and parasitic fleas were collected and classified. The ecological method was used to analyze the species composition, distribution, and seasonal density variation of rodents, and Excel 2010 software was used to analyze data and draw charts. Results The quadrat method was used to investigate 20 quadrats, and no rodents were captured. The five-meter traping method was used to investigate 166 sites, and 266 rodents were captured by 16 600 traps and were classified into 8 species, 5 genera, and 3 families, with a capture rate of 1.60%. Time variation showed a rodent density of <1.00% from October to June in the next year, especially from December to April in the next year. Apodemus agrarius and Cricetulus barabensis were the main rodent species, and the rodent density was 6.14% in July and 5.93% in September. There was a variety of rodent species, mainly A. agrarius, C. migratorius, C. barabensis, A. peninsulae, and A. draco. A total of 266 rodents were examined, among which 36 were found to have fleas, with a flea infestation rate of 13.53%, and a total of 100 fleas were collected and classified into 7 species, 5 genera, and 3 families, with a mean flea index of 0.38. Bacteriological and serological tests were performed for all materials and yielded negative results. Conclusion Main host animals and fleas in Hebei province and surrounding natural plague foci are not found in the Zhangjiakou competition area and the surrounding area, and there are differences in natural landscape, the species composition of rodents, and the composition of fleas between the Zhangjiakou competition zone and natural plague foci in Hebei province. Therefore, there is a relatively low risk of primary animal plague in the local area.
  • An investigation of rodent and cockroach infestations in underground tube wells in Beijing, China, 2019
    LI Qiu-hong, LIU Mei-de, ZHOU Xiao-jie, FU Xue-feng, LIU Ting, ZHANG Yong, TONG Ying
    Chines Journal of Vector Biology and Control. 2021, 32(2): 165-168. https://doi.org/10.11853/j.issn.1003.8280.2021.02.009
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    Objective To study the rodent and cockroach infestations in underground tube wells in Beijing, China, and to provide a scientific basis for prevention and control strategies. Methods A total of 100 streets were selected in Beijing in 2019, and 50 underground tube wells were selected randomly in each street for monitoring (four times). Bait stealing and visual inspection were used for rodent and cockroach density monitoring, respectively. The data were recorded in Excel 2007 software, and a descriptive analysis was conducted. Results Among all the underground tube wells selected in Beijing, the mean value of rodent positivity was 1.06%, and the mean value of cockroach positivity was 0.04%. The number of rodent-positive tube wells was highest (28) in Chaoyang and Haidian districts and lowest (2) in Shunyi district. There were 7 cockroach-positive tube wells, 3 in Fengtai district, 3 in Xicheng district, and 1 in Dongcheng district. Compared with the rural areas, the urban areas had a higher rodent-positive rate of tube wells. Sewage wells had the highest rodent-positive rate (46.92%), followed by electric wells (26.07%) and other wells (12.79%). The main cockroach-infested wells were sewage wells, rainwater wells, and electric wells. Conclusion Varying degrees of rodent infestation were found in the underground tube wells of Beijing in 2019, more severe in the urban areas than in the rural areas. Some administrative divisions had cockroach infestation. Rodent prevention and control in underground tube wells must not be overlooked, and cockroach infestation in underground tube wells should also be closely monitored.
  • Surveillance and analysis of mosquito density and seasonal fluctuation in Liaoning province, China, 2014-2018
    DING Jun, WANG Chun-yu, BAI Yu-yin, ZHANG Ji-bo
    Chines Journal of Vector Biology and Control. 2021, 32(2): 169-172. https://doi.org/10.11853/j.issn.1003.8280.2021.02.010
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    Objective To investigate the seasonal fluctuation of mosquito density in Liaoning province, China, and to provide a scientific basis for mosquito control and risk assessment, early warning, and prevention and control of mosquito-borne diseases. Methods From 2014 to 2018, mosquito density was monitored by the lamp trapping method from May to October in five mosquito habitats within urban areas (residential areas, parks, and hospitals) and rural areas (rural households and livestock sheds) of Liaoning province. Mosquito composition, density, and seasonal fluctuation were analyzed. Results From 2014 to 2018, a total of 7 000 mosquito traps were set up in Liaoning province and 275 736 mosquitoes were caught. In terms of mosquito species composition, Culex pipiens pallens, Anopheles sinensis, and Cx. tritaeniorhynchus were the top three, accounting for 24.59%, 21.01%, and 19.06% of the total mosquito counts, respectively. The overall mosquito density was 19.70 mosquitoes/lamp·hour. From 2014 to 2018, the mosquito density in each year was 16.75, 26.05, 15.83, 20.23, and 19.65 mosquitoes/lamp·hour, respectively. In terms of mosquito habitats, livestock sheds had the highest mosquito density (72.60 mosquitoes/lamp·hour), while hospitals had the lowest (2.40 mosquitoes/lamp·hour). In each year, the overall mosquito density fluctuated seasonally with a single peak in early or late August. Conclusion For mosquito control in Liaoning province, livestock sheds and rural households are the key places and the May to October period is the key time. Vector mosquito surveillance at each surveillance site should continue to be strengthened to provide a basis for the sustainable control of mosquitoes and mosquito-borne infectious diseases.
  • Epidemiological characteristics of dengue fever and monitoring of Aedes vector mosquitoes in Dehong Dai and Jingpo autonomous prefecture of Yunnan province, China, 2013-2019
    LIU Yong-hua, YIN Xiao-xiong, ZHANG Hai-lin, YANG Zhao-lan, DONG Chao-liang, CHEN Si-yu, GUO Zhao-sheng, LI Ping
    Chines Journal of Vector Biology and Control. 2021, 32(2): 173-180. https://doi.org/10.11853/j.issn.1003.8280.2021.02.011
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    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.
  • Bartonella distribution in naturally infected rodent tissues
    LI Dong-mei, XU Ai-ling, SONG Xiu-ping, LI Qing-duo, KANG Yang, LIU Qi-yong
    Chines Journal of Vector Biology and Control. 2021, 32(2): 181-187. https://doi.org/10.11853/j.issn.1003.8280.2021.02.012
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    Objective To investigate the distribution of Bartonella in different tissues of rodents with natural infections. Methods The night trapping method was used to capture rodents around Mishan Port of Heilongjiang province, China in May 2018. The heart, liver, spleen, lung, and kidney were homogenized and incubated, and Bartonella DNA was extracted from suspected colonies. Citrate synthase gene (gltA) was PCR-amplified and sequenced to determine the species of Bartonella. The infection rates of these tissues were analyzed and compared. Results A total of 81 rodents of seven species were captured, including Apodemus agrarius (68, 84.0%), Microtus fortis, M. maximowiczii, Tamias sibiricus, and others. Bartonella strains were isolated from 45 rodents of four species, with an overall infection rate of 55.6%. The infection rates of the heart, liver, spleen, lung, and kidney were 38.3% (31/81), 39.5% (32/81), 42.0% (34/81), 32.1% (26/81), and 45.7% (37/81), respectively, which were not significantly different from each other (χ2=5.623, P=0.229). The 45 isolates were identified as seven species of Bartonella, i.e., B. grahamii, B. heixiaziensis, B. japonica, B. coopersplainsensis, B. taylorii, B. washoensis, and a novel species. B. grahamii was the predominant species (73.3%) and was isolated from multiple tissues, though the differences were not statistically significant (χ2=7.492, P=0.112). Conclusion Bartonella has a high natural infection rate in rodents and can invade various tissues with similar tissue tropism, and the infection is not constrained by host and Bartonella species.
  • Surveillance of mosquitoes and their virus infection in Wudu district, Longnan, Gansu province, China, 2017-2019
    WANG Xiao-jun, CAI Yu-cheng, REN Gui-qing, TONG Bo-bo, JIA Xu-zhen
    Chines Journal of Vector Biology and Control. 2021, 32(2): 188-192. https://doi.org/10.11853/j.issn.1003.8280.2021.02.013
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    Objective To investigate mosquito population distribution and mosquito virus infection in Wudu district, Longnan, Gansu province, China, and to provide a scientific basis for prevention and control of mosquito-borne infectious diseases. Methods Adult mosquito density was monitored in Wudu district from 2017 to 2019 using the light trapping method. Specific real-time PCR was used to detect Japanese encephalitis virus (JEV) and West Nile virus (WNV) in captured mosquitoes. Results A total of 15 796 female mosquitoes were captured from 2017 to 2019. The dominant species were Culex pipiens pallens (49.30%) and Cx. tritaeniorhynchus (45.59%). The mosquito density was highest in livestock sheds (104.76 mosquitoes/light·night). Cx. tritaeniorhynchus was the most abundant in livestock sheds (77.96%), followed by farmhouses (9.17%). The annual mean mosquito density increased continuously, and the differences were statistically significant (χ2=32.955, P<0.05). Mosquito density showed unimodal distribution and peaked in June to August, with the highest density in July 2019 (143.05 mosquitoes/light·night). The number of Cx. tritaeniorhynchus captured from June to August accounted for 92.20% (6 639/7 201) of the total number of this species. A total of 28 specimens were made from the 1 074 female mosquitoes captured from July 29 to 30, 2019 and sent to the Virus Laboratory of the Chinese Center for Disease Control and Prevention for nucleic acid detection of JEV and WNV, and the positive rates of JEV and WNV were 21.43% (6/28) and 0, respectively. Conclusion The density of mosquito vectors in Wudu district was relatively high, the proportion of Cx. tritaeniorhynchus increased from 2017 to 2019, and JEV was detected in mosquitoes. The high risk of mosquito-borne infectious diseases requires intensified mosquito control measures to reduce mosquito density and effectively suppress the occurrence of mosquito-borne infectious diseases.
  • An analysis of resistance of Blattella germanica to commonly used insecticides in Wuxi, Jiangsu province, China, 2010-2018
    ZOU Ya-ming, LAN Ce-jie, ZHU Ding, YOU Ying-qi, LIU Yun-hua, CHEN En-pin
    Chines Journal of Vector Biology and Control. 2021, 32(2): 193-196. https://doi.org/10.11853/j.issn.1003.8280.2021.02.014
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    Objective To analyze the resistance of Blattella germanica to commonly used insecticides in Wuxi, Jiangsu province, China in the past 10 years. Methods Every two years from 2010 to 2018, B. germanica was captured by electric suction device and mechanic trapping devices in farmer's markets, restaurants, and food trading centers in Wuxi. Captured cockroaches were brought back to the laboratory, reared for one generation, and insecticide resistance was measured by the residual film method. Results The resistance ratio (RR) of B. germanica to beta-cypermethrin was 8.25 (2010), 9.94 (2012), 5.78 (2014), 12.39 (2016), and 6.06 (2018). The RR to deltamethrin was 14.02 (2012), 6.27 (2014), 16.75 (2016), and 10.79 (2018). The RR to propoxur was 1.75 (2010), 1.48 (2012), 1.32 (2014), 2.53 (2016), and 1.24 (2018). The RR to acephate was 2.14 (2010), 1.31 (2012), 1.01 (2014), 1.03 (2016), and 0.76 (2018). The RR to chlorpyrifos was 0.91 (2014), 2.09 (2016), and 0.39 (2018). Conclusion The resistance of B. germanica to beta-cypermethrin and deltamethrin increased from 2010 to 2018 in Wuxi, with medium to high levels of resistance; the resistance to propoxur, acephate, and chlorpyrifos decreased slowly and showed overall sensitive to low levels of resistance.
    • Vector Infectious Disease
  • Epidemiological characteristics of Japanese encephalitis in eight provinces and municipalities of northern China, 2005-2019
    WANG Zhi-hui, LI Wen, GUO Yu-hong, YUE Yu-juan, WANG Jun, MA Xin-ran, XU Ming-fang, WU Hai-xia, LIU Qi-yong, MENG Feng-xia
    Chines Journal of Vector Biology and Control. 2021, 32(2): 197-203. https://doi.org/10.11853/j.issn.1003.8280.2021.02.015
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    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 (χ2trend=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.
    • Taxonnomy and Fauna of Vectors Reoprt Series
  • Taxonomy and fauna of Siphonaptera in Tibet autonomous region, China V. Palaeopsylla medimina and P. polyspina were discovered for the first time in Tibet autonomous region(Siphonaptera: Ctenophthalmidae)
    WEN Xiang-bing, DENGZENG Duo-jie, BA Sang, MA Bing-cheng, YANG Xiao-dong, XU Xiang, LI Chun-fu, Chen Zi-long, ZHOU Hong-ning, GONG Zheng-da
    Chines Journal of Vector Biology and Control. 2021, 32(2): 204-207. https://doi.org/10.11853/j.issn.1003.8280.2021.02.016
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    Objective To investigate and understand the fauna and distribution of fleas in Tibet autonomous region (Tibet), and to provide a basis for further research on the fauna of fleas in Tibet. Methods With Linzhi in southeastern Tibet as the spatial scope of investigation and research, small mammals and their parasitic fleas in farming areas at different altitudes were selected as the research objects. From October to November, 2018, large rat traps were used for the investigation and sampling of the small mammals and their parasitic fleas, and the samples were classified and identified in the laboratory. Results A batch of Palaeopsylla Wagner, 1903, specimens were collected and identified as P. helena Lewis, 1973, P. incurva Jordan, 1932, P. medimina Xie et Gong, 1989, and P. polyspina Xie et Gong, 1989, among which P. medimina and P. polyspina were found for the first time in Tibet, setting a new record for flea species in this region. This article recorded and reported the main identification characteristics, distribution areas, host animals, and the head and genital abdominal segments of the two newly recorded species. In addition, this article discussed the geographical distribution of Palaeopsylla in China. Conclusion Up to now, seven species of Palaeopsylla have been known in Tibet Autonomous Region, accounting for 23% of the total number of species in China.
    • Technology and Method
  • A study of grid monitoring method for mosquito ovitraps
    ZHANG Jia-yi, ZHOU Yi-bin, LI Yan-ling, ZHONG Ling
    Chines Journal of Vector Biology and Control. 2021, 32(2): 208-212. https://doi.org/10.11853/j.issn.1003.8280.2021.02.017
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    Objective To investigate the grid monitoring method for mosquito ovitraps based on spatial analysis technology, and to provide a basis for accurate delineation of spatial range for dengue fever prevention and control. Methods From week 20 to week 45 of 2019, 133 grids were established in Jing'an district of Shanghai, and the mosquito ovitrap method was used to monitor the temporal and spatial variations in the density of Aedes albopictus once a week. The global spatial autocorrelation Moran's I index was calculated for the positive rate of mosquito ovitraps to detect the spatial aggregation pattern of Ae. albopictus in the study area, and a hot spot analysis was used to identify the hot and cold spots with statistical significance. Results In the study area, the mean positive rate of mosquito ovitraps reached the maximum value of 8.28% in the week 29 of 2019. The global spatial autocorrelation analysis showed that Moran's I index at sub-district scale was -0.012 (Z=0.384, P=0.701) and the positive rate of mosquito ovitraps showed a spatial pattern of random distribution at sub-district scale; Moran's I index at grid scale was 0.150 (Z=3.074, P=0.002), and the positive rate of mosquito ovitraps showed a spatial pattern of aggregated distribution at grid scale. Hot spots of the positive rate of mosquito ovitraps showed high-aggregation spots in the south and low-aggregation spots in the middle at both grid and sub-district scales, and the high-aggregation spots in the north detected at grid scale were not found at sub-district scale. Conclusion Grid-scale mosquito ovitrap monitoring helps to identify the high- and low-aggregation areas of Ae. albopictus, and the grid monitoring method has practical significance.
    • Investigation
  • An investigation of mosquito species and perching habit in Yuewu and Bangnai counties of the Lao People's Democratic Republic
    WU Lin-bo, DONG Xue-shu, YANG Rui
    Chines Journal of Vector Biology and Control. 2021, 32(2): 213-216. https://doi.org/10.11853/j.issn.1003.8280.2021.02.018
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    Objective To investigate the composition and perching habit of mosquito species in Yuewu and Bangnai counties of The Lao People's Democratic Republic (Laos), and to provide a basis for the classification of mosquito species and the prevention and treatment of insect-borne infectious diseases. Methods In June 21-29 and July 8-11, 2019, the mosquito trap lamp was used to collect adult mosquitoes in human and livestock houses in Yuewu and Bangnai counties of Laos, and the species and number of adult mosquitoes were determined by morphological taxonomic identification under a stereomicroscope. At the same time, the spoon method was used to collect the larvae, which were fed to adult mosquitoes and were used to make pinned specimens. Results A total of 17 053 mosquitoes, belonging to 32 species in 8 subgenera and 2 subfamilies, were collected by mosquito trap lamp, among which Culex subfamily accounted for 89.66% (15 290/17 053) of total mosquitoes. Culex tritaeniorhynchus was the dominant mosquito species in Yuewu and Bangnai counties, which accounted for 82.03% (13 719/16 724) and 41.95% (138/329), respectively, of all mosquitoes in these two counties. The mosquito density was 232.28 and 10.28 mosquitoes/lamp·night, respectively, in Yuewu and Bangnai counties. Three species of mosquitoes were collected by the spoon method, namely, Mimomyia (Etorleptiomyia) luzonensis (Ludlow, 1905), Aedes (Collessius) macfarlanei (Edwards, 1914), and Cx. (Eumelanomyia) brevipalis (Giles, 1902). Conclusion There are abundant mosquito species in Yuewu and Bangnai counties of Laos, with Cx. tritaeniorhynchus as the dominant mosquito species in these regions, and livestock houses are the main habitat of mosquitoes.
    • Taxonomic Identification
  • Identification of a Brucella strain isolated from Marmota himalayana in Qinghai province, China
    ZHANG Ai-ping, XU Li-qing, MA Li, LI Ji-quan, XUE Hong-mei, WANG Jian-ling, YANG Xu-xin, XIE Hui, ZHAO Yuan-bo, YU Shou-hong
    Chines Journal of Vector Biology and Control. 2021, 32(2): 217-220. https://doi.org/10.11853/j.issn.1003.8280.2021.02.019
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    Objective To perform species identification of Brucella isolated from the whole blood of Marmota himalayana by PCR. Methods A total of 245 whole blood samples were collected from M. himalayana in Qinghai province, China in 2016. Serum was isolated, and the Rose Bengal plate test and the tube agglutination test were used to detect brucellosis antibody. The blood culture method was used to perform bacterial culture of the whole blood samples of M. himalayana with positive antibody. The test results were observed and suspected Brucella strains were isolated and purified. Smear microscopy and the bacteriophage lysis test were performed for the purified suspected Brucella strains, nucleic acid was extracted to prepare templates, and then BCSP31-PCR and AMOS-PCR were used to identify Brucella strains. Results One suspected Brucella strain was isolated with the same morphology and staining characteristics as Gram-negative bacilli. The bacteriophage lysis test showed lysis of BK2 and non-lysis of Tb, and the strain could agglutinate with the single-phase specific serum A and M; therefore, the strain was identified as Brucella melitensis type Ⅲ. BCSP31-PCR agarose gel electrophoresis showed a specific target band at 223 bp, and AMOS-PCR agarose gel electrophoresis showed a specific target band at 731 bp; the strain was proved to be B. melitensis. Conclusion A Brucella strain is isolated for the first time from 245 whole blood samples of M. himalayana and is confirmed to be B. melitensis by PCR in Qinghai province.
  • Microbiochemical identification of a Brucella strain isolated from Marmota himalayana in Qinghai province, China
    XUE Hong-mei, XIE Hui, MA Li, ZHANG Ai-ping, YU Shou-hong, LI Ji-quan, YANG Xu-xin, XU Li-qing
    Chines Journal of Vector Biology and Control. 2021, 32(2): 221-223. https://doi.org/10.11853/j.issn.1003.8280.2021.02.020
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    Objective To perform microbiochemical identification of a suspected Brucella strain isolated from Marmota himalayana in Qinghai province, China in 2017. Methods The isolated bacteria strains were detected by microbiochemical tube and routine pathogenic identification, and the results were compared with the results of three standard Brucella strains. Results Microbiochemical identification showed that the strain could oxidize urea and did not oxidize ornithine, lysine, D-galactose, sorbitol, xylose, and gluconate. Therefore, it was identified as Brucella melitensis. Conclusion Microbiochemical identification of bacteria is rapid and simple, and can provide an experimental basis for the detection of Brucella.
  • Isolation and identification of culturable intestinal bacteria from Clogmia albipunctata larvae and analysis of their digestive enzyme-producing activities
    HE Zhi-wei, DONG Qi-yu, LIU Rui, LI Xin, LIU Xin, XU Cong-wu, ZHAO Xin-qi, WAN Qing, ZHANG Zhong
    Chines Journal of Vector Biology and Control. 2021, 32(2): 224-229. https://doi.org/10.11853/j.issn.1003.8280.2021.02.021
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    Objective To isolate culturable intestinal bacteria from Clogmia albipunctata larvae, determine the digestive enzyme-producing activity and drug resistance of the bacteria, and to explore the effects of intestinal bacteria on food digestion and acclimatization of C. albipunctata. Methods The traditional isolation and culture method was used for the isolation and purification of culturable intestinal bacteria from C. albipunctata larvae, and 16S rRNA sequencing was used for identification. The flat transparent circle method was applied to screen for bacteria producing amylase, protease, cellulase, or lipase. The ratio of transparent circle diameter (D) to bacterial colony diameter (d) was calculated to compare the digestive enzyme-producing activities of different bacteria. Statistical analysis was performed using SPSS 20.0 software. The one-way analysis of variance was used for comparison between groups. When the variance is homogeneous, S-N-K multiple comparison was performed; when the variance is not homogeneous, the Dunnett's T3 test was performed. The paper disk diffusion method was used to analyze the drug susceptibility of different culturable intestinal bacteria. Results A total of 12 species of bacteria belonging to 5 genera were isolated from the intestine of C. albipunctata larvae. There were 7 species belonging to the genus Bacillus-B. vietnamensis, B. subtilis subsp., B. thuringiensis, B. aryabhattai, B. cereus, Lysinibacillus fusiformis, and L. pakistanensis. There were 2 species belonging to the genus Enterococcus-E. casseliflavus and E. gallinarum. There was 1 species each belonging to the genus Exiguobacterium, Leucobacter, and Staphylococcus-E. profundum, L. celer subsp., and S. sciuri. Among these bacteria, 8 species showed amylase-producing activity, 6 species showed protease-producing activity, and no bacteria showed cellulase- or lipase-producing activity. There was a significant difference in amylase-producing activity between the 8 species of bacteria (F=8.779, P<0.001). B. vietnamensis, B. subtilis subsp. and E. profundum had relatively high activity of producing amylase. There was a significant difference in protease-producing activity between the 6 species of bacteria (F=23.980, P<0.001). B. vietnamensis and B. subtilis subsp. had relatively high activity of producing protease. In drug susceptibility tests, S. sciuri showed resistance to 6 antibiotics, E. gallinarum were resistant to 5 antibiotics, and B. aryabhattai and E. casseliflavus showed resistance to 4 antibiotics. Conclusion The culturable intestinal bacteria from C. albipunctata larvae have the ability to produce amylase and protease, which may assist in digestion and breakdown of food. The intestinal bacteria generally have certain drug resistance, which can help C. albipunctata larvae survive in a dirty environment.
  • Molecular and morphological identification of Cheyletus malaccensis and C. carnifex
    LI Xin-mei, SUN Meng-tao, ZHAN Yu-juan, ZHANG Lan-xiang, LI Meng-zhu, TAO Dong-dong, SUN En-tao
    Chines Journal of Vector Biology and Control. 2021, 32(2): 230-234. https://doi.org/10.11853/j.issn.1003.8280.2021.02.022
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    Objective To investigate methods for the morphological and molecular identification of Cheyletus malaccensis and C. carnifex. Methods From May 2018 to July 2019, C. malaccensis and C. carnifex were obtained from the storage samples of some farmers' granaries in several areas of Anhui province. The morphological characteristics of C. malaccensis and C. carnifex were compared and described. MEGA X software was used to analyze mitochondrial cytochrome c oxidase subunit Ⅰ (COⅠ) gene sequence for C. malaccensis and C. carnifex, and the maximum likelihood method was used to construct the phylogenetic tree. Results C. malaccensis and C. carnifex had similar morphological characteristics, while morphological identification could be performed under a light microscope based on the shape of peritremes, the morphology of guard seta of tarsus I, and the length-ratio between solenidia and pretarsus of tarsus I. Based on the COⅠ gene, the interspecific genetic distance was >0.02 and the intraspecific genetic distance was <0.02. The base composition analysis showed that the sequence had an obvious A+T bias, and the results of BLAST were consistent with those of morphological identification. Phylogenetic tree showed that C. malaccensis and C. carnifex were clustered into one single branch, respectively. Conclusion Identification of C. malaccensis and C. carnifex can be performed based on the external morphological characteristics and the mitochondrial COⅠ gene, and the combination of these two methods can improve the accuracy of the identification of closely related species.
    • Control Experiment
  • A preliminary investigation of the flea control effect of beta-cypermethrin in some rural residential areas of Xinjiang Uygur autonomous region, China
    WANG Qi-guo, WANG Xin-hui, ABUDUREXITI Abulikemu, CHEN Ling-xia, LUO Tao, BAOKAIXI Guliayi, GUI You-jun, WANG Cheng, LI Wei, ZHANG Xiao-bing
    Chines Journal of Vector Biology and Control. 2021, 32(2): 235-238. https://doi.org/10.11853/j.issn.1003.8280.2021.02.023
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    Objective To investigate the flea control effect in some rural residential areas of Xinjiang Uygur autonomous region, China. Methods Some rural residential areas in Xinjiang were selected as the experimental areas, and 8% beta-cypermethrin wettable powder diluted 100 times was used to control the fleas via residual spraying. The flea infestation rate, flea index, and biting rate were compared before and after the flea control to evaluate the control effect. The independent samples t-test or one-way analysis of variance and chi-square test were used to compare the flea index, flea infestation rate, and biting rate. Results Before the flea control, the flea infestation rate was 86.25% (69/80) and the total flea index was 0.23 (213/914), with no significant differences between different villages (P=0.599, Fisher's exact test; F=0.103, P=0.924). The biting rate was 62.71% (148/236), 89.47% (34/38), and 83.82% (57/68), respectively, in adults, young children (6 months to 4 years of age), and elder children (6-8 years of age). The biting rate was significantly higher in young and elder children than in adults (χ2=10.510, P=0.001; χ2=10.714,P=0.001). The biting rate of cadres stationed in the villages was 76.29% (74/97). On days 2-3 after the flea control, the flea infestation rate and total flea index were significantly reduced to 6.25% (5/80) and 0.02 (19/914), respectively (χ2=102.979, P<0.001; t=38.476, P<0.001); the biting rate was significantly reduced to 4.41% (10/227), 8.11% (3/37), and 6.06% (4/66), respectively, in adults, young children, and elder children (χ2=174.983, 49.653, and 85.613, all P<0.001); the biting rate of cadres stationed in the villages was significantly reduced to 2.94% (3/102) (χ2=112.757, P<0.001). Conclusion Residual spraying with 8% beta-cypermethrin wettable powder diluted 100 times had a good effect of flea control in the rural residential areas in Xinjiang, which holds promise for application.
  • Effects of the two insecticide formulations by ultra-low-volume spraying in killing Aedes albopictus:an experimental field study
    QIN Yan-min, ZHANG Shao-hua, LIU Yang, DAI Chuan-wen, CHEN Jia-hui
    Chines Journal of Vector Biology and Control. 2021, 32(2): 239-242. https://doi.org/10.11853/j.issn.1003.8280.2021.02.024
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    Objective To observe the effects of the two insecticide formulations by ultra-low-volume spraying in killing adult Aedes albopictus in the field, and to provide technical parameters for the on-site emergency disposal of dengue fever. Methods Two ultra-low-volume spray formulations (10% meperfluthrin·permethrin aqueous emulsion and 10.4% S-bioallethrin·permethrin aqueous emulsion) were used to kill adult Ae. albopictus from May 31 to June 10, 2019, in a residential area within a jurisdiction in Shenzhen, China. The human induced index method was used to monitor the density of Ae. albopictus, and the density changes of Ae. albopictus in the test and control areas after insecticide application were observed. The paired t-test and Mann-Whitney U test were used to compare the mosquito density at different times after application of different insecticides to evaluate their effects of killing adult mosquitoes. Results The mean relative density of Ae. albopictus decreased by 100%, 99.1%, and 59.5% at 0.5, 1.0, and 24.0 h, respectively, after spraying 10% meperfluthrin·permethrin aqueous emulsion, and by 99.4%, 96.1%, and 54.5% at 0.5, 1.0, and 24.0 h, respectively, after spraying 10.4% S-bioallethrin·permethrin aqueous emulsion. There were significant differences in mosquito density at 1.0 and 24.0 h after spraying of the two insecticides (t=6.176, P=0.025; t=16.411, P=0.004), but no significant difference was observed in mosquito density at 1.0 h after spraying of the two insecticides. The results showed that there was no significant difference in the adult mosquito-killing effect between the two insecticides (Z=-1.348, P=0.178). Conclusion Ultra-low-volume sprays of the two insecticide formulations can quickly reduce the density of adult Ae. albopictus, exhibiting an obvious control effect on Ae. albopictus.
    • Review
  • An overview of tick removal methods
    ZHANG Meng, WANG Tong-xuan, YU Zhi-jun, LIU Jing-ze
    Chines Journal of Vector Biology and Control. 2021, 32(2): 243-246. https://doi.org/10.11853/j.issn.1003.8280.2021.02.025
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    Ticks are obligate bloodsucking arthropods that transmit the most diverse pathogens, and the harm to humans caused by ticks is secondary only to that by mosquitoes. Once a tick bites the human body, it can ingest a large amount of blood and release toxins or pathogens if not removed immediately, which causes great harm to humans. Hence, it is of great importance to remove on-host ticks on the body surface as soon as possible. A huge number of tick biting cases occur in China each year, whereas there still exist controversies regarding how to remove the ticks correctly. It has attracted more and more public attention regarding how to correctly remove the biting ticks to avoid the occurrence of tick-borne diseases and the release of tick-mediated toxins. This article has made a comparative analysis on the tick removal methods in recent years and evaluated the effects of different removal methods as well as their advantages and disadvantages and scope of application. This provides a theoretical foundation for reducing tick-induced harm to humans; meanwhile, it is important for effective prevention and control of ticks and tick-borne diseases.
  • Research advances in ecological habits of Aedes aegypti in Yunnan, China
    LI Yang-si-qi, LI Man, JIA Wen-shuang, ZHOU Hong-ning
    Chines Journal of Vector Biology and Control. 2021, 32(2): 247-253. https://doi.org/10.11853/j.issn.1003.8280.2021.02.026
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    Aedes aegypti is the main vector of important insect-borne infectious diseases including dengue fever, chikungunya fever, and Zika virus disease, which are prevalent in tropical and subtropical regions. In recent years, with the influence of El Nino and the rapid development of global trade and transportation, the distribution of Ae. aegypti has increasingly expanded, and the risk of the transmission of these diseases has gradually increased. By searching for and comprehensively analyzing related articles in China and globally, this article reviews the research advances in the distribution of Ae. aegypti and its important ecological habits and arbovirus-carrying rates in Yunnan, in order to provide a reference for the surveillance and control of dengue vector.
  • The strategies of “early detection, early report, early assessment, and early control” in vector prevention and control
    ZHAO Qi, WU Wen, HUANG Hua
    Chines Journal of Vector Biology and Control. 2021, 32(2): 254-256. https://doi.org/10.11853/j.issn.1003.8280.2021.02.027
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    Since the outbreak of coronavirus disease 2019 (COVID-19), the social prevention and control measures of "early detection, early report, early isolation, and early treatment" have been widely used in the public health field and are widely accepted by the general public. In the practice of integrated vector management, Henan province gives full play to the advantages of mobilization and coordination of the Patriotic Health Campaign, establishes a work path of "early detection, early report, early assessment, and early control", the strategies of "four early". It defines the responsibilities of government, departments, territories, and individuals, and clarifies the working concepts of integrated vector management, which helps to form societal forces and promote the development of vector control in Henan province. This article analyzes the strategies of "four early" in integrated vector management in Henan province, in order to provide a reference for vector management strategies in China.
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