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Study on the lethal rate of six active ingredients to Blattella germanica and Periplaneta americana
TANG Li-ping, ZHU Jian, LIAO Guo-dong, WU Ying-hua
Abstract714)      PDF (749KB)(225)      
Objective To test and compare the speed of death of Blattella germanica and Periplaneta americana treated with six active ingredients, and to provide theoretical basis for consumers' experience. Methods Using the open square box method, 30 test insects were starved for one day had allowed access to cockroach baits containing each of the six effective components. The number of dead insects was counted at regular time intervals, and LT 50 and LT 95 were calculated according to the weighted linear regression method. Results Without other feed, the LT 50 for B. germanica was in the order of 0.5% dinotefuran>2.5% imidacloprid>1.5% propoxur>0.05% fipronil>0.2% chlorpyrifos>0.1% indoxacarb, and the order of the LT 50 for P. americana was 2.5% imidacloprid>0.05% fipronil>0.2% chlorpyrifos>1.5% propoxur>0.1% indoxacarb. The LT 95 for B. germanica was in the order of 0.5% dinotefuran>2.5% imidacloprid>0.05% fipronil>0.2% chlorpyrifos>0.1% indoxacarb>1.5% propoxur, and the LT 95 for P. americana was in the order of 0.2% chlorpyrifos>0.05% fipronil>0.1% indoxacarb>1.5% propoxur>2.5% imidacloprid. Dinotefuran had almost no toxic effect on P. americana. Cockroaches fed less on the diets of dinotefuran, imidacloprid and propoxur, which had a faster death rate in the early stage, and fed more on the diets of chlorpyrifos, fipronil and indoxacarb, which had a slower death rate in the early stage. Conclusion On the whole, cockroach baits with different active ingredients had different lethal rates to different species of cockroaches. Dinotefuran, imidacloprid and propoxur were quicker to kill B. germanica, while chlorpyrifos and fipronil were quicker to kill P. americana.
2022, 33 (3): 340-345.   doi: 10.11853/j.issn.1003.8280.2022.03.005
Advances and achievements in the surveillance and control of vectors and vector-borne diseases in China,2012-2021
LIU Qi-yong, LIU Xiao-bo, CHANG Nan, ZHANG Lu
Abstract405)      PDF (1117KB)(283)      
Objective To analyze the policies,strategies,techniques,actions,and achievements in the surveillance and control of vectors and vector-borne diseases in China since 2012. Methods Descriptive epidemiological methods were used to analyze and summarize the epidemiologic situation and challenges of vectors and vector-borne diseases,the surveillance of vectors,and the advances in the control of vectors and vector-borne diseases in China in the past ten years.The Mann-Kendall test was used to analyze the trend of the incidence rate of vector-borne diseases in the past decade using R 4.0.4 software. Results A series of policies,strategies,measures,and techniques were formulated and released for sustainable vector management in China in the past decade.The vector surveillance program in China had been continuously upgraded and improved,and a national vector surveillance network integrating ecology,etiology,and insecticide resistance had been established and improved.The number of national vector surveillance sites (1 097) in 2021 was increased by 54 times,and the funds input in national vector surveillance was increased by 127 times.Direct network reporting was realized for surveillance data,and there was a significant increase in the timely utilization rate of surveillance data,which provided better support for risk assessment,prediction and early warning,decision making,and control effect evaluation.The total annual incidence rate of vector-borne diseases in China in 2021(3.060/100 000) was reduced by 8.66% compared with that in 2007-2011(3.350/100 000),and the total annual mortality rate of vector-borne diseases in 2021(0.016/100 000) was reduced by 33.33% compared with that in 2007-2011(0.024/100 000).China had achieved the goal of malaria elimination and mitigated the accelerating increases in the incidence rates of dengue fever,scrub typhus,and severe fever with thrombocytopenia syndrome. Conclusion In 2012-2021,leapfrog development has been achieved for the policies,strategies,techniques,and actions for the surveillance and control of vectors and vector-borne diseases in China,and there are significant reductions in the incidence and mortality rates of vector-borne diseases.In view of the natural and social driving factors at present,the prevention and control of vectors and vector-borne diseases still face severe challenges,and therefore,it is urgent to further promote the strategies and measures for sustainable vector management,implement Global Vector Control Response 2017-2030,build proactive defense based on"reverse microbial etiology",so as to prevent and control major vector-borne diseases.
2022, 33 (5): 613-621.   doi: 10.11853/j.issn.1003.8280.2022.05.001
Application of geospatial big data and artificial intelligence in driving factor identification and risk prediction for urban dengue fever
LI Zhi-chao, DONG Jin-wei, LIU Qi-yong
Abstract387)      PDF (497KB)(308)      
Dengue fever is a mosquito-borne viral infectious disease that is widely distributed in urban or peri-urban areas in the tropical, subtropical, and warm temperate zones worldwide and threatens the health of populations in more than 100 countries and regions. Global climate change, urbanization, and urban population growth have created favorable conditions for the spread of dengue fever virus. At present, due to a lack of vaccines applicable for mass vaccination, Aedes vector control is the main measure for the prevention and control of dengue fever, and accurate and timely risk prediction for dengue fever can provide an important basis for precise prevention and control, and decision-making. In recent years, the development of geospatial big data promotes the identification of the driving factors for dengue fever at different spatial and temporal scales, and the advances in artificial intelligence, especially the emergence of various deep learning networks, provide new techniques for the risk prediction of dengue fever. Through a comprehensive analysis of the various types of driving factors for dengue fever and their mechanism of action, geospatial big data, and artificial intelligence techniques, this article elaborates on the application of geospatial big data in identifying the driving factors for dengue fever from the aspects of urban land use, climate and environment conditions, and population movement, as well as the current status of the application of artificial intelligence algorithms in predicting the risk of dengue fever transmission. Based on the current research status of geospatial big data and artificial intelligence, it is proposed that future research should develop spatiotemporal risk predictive models at different spatial and temporal scales and the performance of such models should be evaluated in terms of the difference between predicted and true values, the spatiotemporal aggregation patterns of dengue fever, and the actual needs of dengue fever prevention and control.
2022, 33 (3): 321-325.   doi: 10.11853/j.issn.1003.8280.2022.03.001
Comparative study on the killing efficacy of 15% beta-cypermethrin·propoxur suspension concentrate and other four insecticides on millipede
ZHENG Feng-yun, CHEN Feng-ling, HUANG He
Abstract358)      PDF (495KB)(98)      
Objective To investigate the killing efficacy of several commonly used public health insecticides for the control of millipedes, and to provide scientific evidence for millipede control. Methods The insecticide screening test was performed to determine the toxicity of five insecticides with different insecticidal mechanisms to millipedes. The median lethal dose (LD 50) of 15% beta-cypermethrin·propoxur suspension concentrate (SC) was estimated, followed by simulated filed testing to verify its killing efficacy. Excel 2016 and SPSS 19.0 softwares were used for data analysis. The Chi-squared test was used to compare the knockdown effects of different insecticides on millipedes. Results The insecticide screening test showed that the 100 fold dilutions of 15% beta-cypermethrin·propoxur SC, 12% beta-cypermethrin·chlorpyrifos emulsifiable concentrate (EC), 10% lambda-cyhalothrin wettable powder, 20% propoxur EC, and 10% imidacloprid SC had:median knockdown times (KT 50) being 1.78, 8.55, 43.17, 1.15, and 9.23 min, respectively; times taken to knockdown 90% of millipedes (KT 90) being 2.63, 20.02, 68.83, 2.03, and 22.80 min, respectively; 2-h mortality rates after insecticide application being 76.25%, 56.25%, 73.33%, 56.67%, and 46.67%, respectively; and 24-h mortality rates all being 100%. The 200 fold dilutions of the five insecticides had:KT 50 being 2.08, 23.26, 56.00, 1.49, and 52.78 min, respectively; KT 90 being 3.15, 33.35, 85.68, 2.98, and 79.55 min, respectively; 2-h mortality rates being 65.00%, 47.50%, 68.33%, 40.00%, and 36.67%; and 24-h mortality rates all being 100%. The laboratory toxicity test showed that the LD 50 of 15% beta-cypermethrin·propoxur SC against millipedes was 5.42 mg AI/m 2. The simulated field test showed that the 24-h mortality rates of millipedes with 15% beta-cypermethrin·propoxur SC at 7.5, 15.0, and 30.0 mg AI/m 2 were 98.33%, 100%, and 100%, respectively. Conclusion Among the five commonly used insecticides, 15% beta-cypermethrin·propoxur SC has relatively excellent efficacy in killing millipedes, which provides a reference for insecticide selection to control millipedes in public environment.
2022, 33 (3): 438-441.   doi: 10.11853/j.issn.1003.8280.2022.03.024
An investigation of mosquitoes in urban Tengchong, Yunnan province, China, 2018-2020
LI Xi-shang, WANG Jia-zhi, LI Sheng-guo, TANG Zong-yan, YANG Dong-hai, YIN Shou-qin, WANG Xing-juan, LI Zeng-zhu, CAI Wen-bin
Abstract293)      PDF (573KB)(128)      
Objective To investigate the species composition, spatial distribution, population density, and seasonal fluctuation of mosquitoes in the urban area of Tengchong, Yunnan province, China, and to provide a scientific basis for mosquito prevention and control. Methods Adult mosquitoes were captured by the light trap method. Aedes albopictus larvae were investigated using the Breteau index (BI). The F test and Chi-squared test (or Fisher's exact test) were used for data analysis. Results A total of 61 810 adult mosquitoes were captured from 2018 to 2020, involving 12 species of 5 genera. The dominant species were Culex pipiens quinquefasciatus and Cx. tritaeniorhynchus in the urban area, and Anopheles sinensis and Cx. tritaeniorhynchus in the suburban area. The average mosquito density was 2 183.32 mosquitoes/light·night in cattle sheds in the suburban area, 12.29 mosquitoes/light·night in hospitals, 4.93 mosquitoes/light·night in schools, 4.29 mosquitoes/light·night in parks, and 2.68 mosquitoes/light·night in residential areas. A total of 11 986 containers were examined for Aedes larvae. There were 80 positive containers, all of which were positive for Ae. albopictus larvae. The average BI was 0.66. Conclusion The species composition, spatial distribution, population density, and seasonal fluctuation of mosquitoes in the urban area of Tengchong are preliminarily understood. Control measures should depend on the seasonal fluctuation of mosquito density and the breeding environment of mosquito.
2022, 33 (3): 356-359.   doi: 10.11853/j.issn.1003.8280.2022.03.008
Morphological identification of two non-recorded cockroach species (Latindiinae: Latindia) firstly intercepted in China
LI Ting-ting, LIU De-xing, CHEN Jian, WEI Xiao-ya, QIU De-yi, KE Ming-jian, YUE Qiao-yun
Abstract244)      PDF (31134KB)(207)      
Objective To morphologically identify two cockroaches intercepted from logs imported from French Guiana at Zhongshan port,Guangdong province,China on March 9 and May 11,2021. Methods The genus was preliminarily identified based on morphological characteristics.The species was determined according to the literature of this genus in South America where the logs were sourced from. Results The male cockroach intercepted on March 9 was Latindia dohrniana Saussure&Zehntner,1894.The male cockroach intercepted on May 11 was an unrecorded new species, Latindia sp .nov. Conclusion Latindia,including the intercepted L.dohrniana and Latindia sp .nov.,has not been recorded in China.This finding can provide a reference for future identification of this cockroach genus intercepted at ports.
2022, 33 (5): 742-747.   doi: 10.11853/j.issn.1003.8280.2022.05.024
Effect of Misgurnus anguillicaudatus in controlling the larvae of Aedes albopictus: A preliminary study
WU Yu-yan, LI Tian-qi, LIU Qin-mei, WANG Jin-na, LUO Ming-yu, GONG Zhen-yu
Abstract243)      PDF (626KB)(233)      
Objective To investigate the effect of Misgurnus anguillicaudatus endemic to China in controlling the larvae of Aedes albopictus, and to provide new ideas for biological control of mosquitos. Methods M. anguillicaudatus individuals were divided into two juvenile and adult groups. After weighing and fasting for 24 h, they were put into tanks with 100, 200, 400, and 1 000 larvae/basin. Gambusia affinis with the same weight was used as control group (multiple G. affinis fish with the same average weight as the two groups of M. anguillicaudatus were used). The numbers of larvae and pupa were counted at 1, 2, 4, 6, 8, and 24 h to compare the ability to devour the larvae of Ae. albopictus between M. anguillicaudatus at different growth stages and between M. anguillicaudatus and G. affinis. Results Each juvenile M. anguillicaudatus devoured 984 larvae per day on average, while each adult M. anguillicaudatus devoured 647 larvae per day on average. With the same density of Ae. albopictus larvae, juvenile M. anguillicaudatus devoured more larvae than G. affinis of the same weight ( F=58.051, P<0.001), whereas adult M. anguillicaudatus devoured fewer larvae than G. affinis of the same weight ( F=23.162, P<0.001). A 7-day experiment was conducted with juvenile M. anguillicaudatus for continuous devouring of larvae. The results showed stable daily devouring of larvae in the short and medium term. There were no significant differences in the number of mosquito larvae devoured per day ( χ 2=2.650, P=0.266), and the number was significantly higher than that of G. affinis of the same weight ( χ 2=16.758, P=0.001). Conclusion M. anguillicaudatus has good ability to devour Ae. albopictus larvae, and can be used as a new method to control mosquito larvae in small water bodies in residential areas.
2022, 33 (4): 453-457.   doi: 10.11853/j.issn.1003.8280.2022.04.001
The concept and connotation of “rodent-borne diseases”: A systematic study
XU Ai-ling, LI Dong-mei, LIU Qi-yong
Abstract242)      PDF (1756KB)(256)      
Objective To investigate the basic concept of "rodent-borne diseases" suitable for national vector surveillance and the list of "rodent-borne diseases" in China. Methods Related keywords were used to search for the articles on "rodent-borne diseases" in the databases and websites of SinoMed,CNKI,Wanfang Data,Super Star Digital Library,PubMed,and Web of Science,and the definition of "rodent-borne diseases" was summarized to determine its concept and coverage. A total of 27 diseases were selected to form the list of major "rodent-borne diseases" in China for expert consultation. Results A total of 178 references were used to formulate the basic concept of "rodent-borne diseases" and its inclusion criteria,and 18 experts consulted all agreed to the concept of "rodent-borne diseases". The information table of "rodent-borne diseases" in China was developed, including 5 viral diseases,12 bacterial diseases, and 8 parasitic diseases. Conclusion "Rodent-borne diseases" are a group of infectious diseases that seriously affect human health,and its basic concept and inclusion conditions are proposed to provide a reference for the comprehensive surveillance of disease-related pathogens carried by rodents and promote the establishment of more perfect control strategies.
2022, 33 (2): 161-170.   doi: 10.11853/j.issn.1003.8280.2022.02.001
An investigation of killing effect of three commercially available aerosols on Cimex lectularius and Attagenus unicolor japonicus
JIA Xiao-kai, WANG Ying, GAO Chun-hua, ZHOU Dan-dan, WEI Fu-rong
Abstract233)      PDF (570KB)(109)      
Objective To investigate the insecticidal effect of three commercially available aerosols on Cimex lectularius and Attagenus unicolor japonicus, and to investigate the sensitivity of these two types of sanitary pests to different insecticidal aerosols. Methods According to the national standard GB/T 13917.2-2009, the cylinder method was used to determine the knockdown rate of C. lectularius and A. unicolor japonicus after 20-min exposure to the aerosols, and the mortality rate at 48 h and 72 h were observed. The Chi-square test was used to compare the 20-min knockdown rate and mortality rate between different groups. Results In the killing test to A. unicolor japonicus, the 20-min knockdown rate, and the mortality rate at 48 h and 72 h of A. unicolor japonicus were all 100% after exposure to the three commercially available aerosols; in the killing test to C. lectularius, the knockdown rates of C. lectularius were 100%, 98.33%, and 90.00%, respectively, after 20-min exposure to No. 1, No. 2, and No.3 aerosols, but the mortality rates of C. lectularius were 100% at 48 h and 72 h after exposure to the three aerosols. There was no significant difference in 20-min knockdown rate between different groups ( χ 2=3.000, P>0.05). Conclusion The killing effect of three commercially available aerosols on C. lectularius and A. unicolor japonicus measured according to the method of the national standard GB/T 13917.2-2009 showed that relatively high knockdown and killing rates can be achieved.
2022, 33 (2): 207-210.   doi: 10.11853/j.issn.1003.8280.2022.02.007
Surveillance and analysis of mosquito population density and seasonal fluctuation in Tangshan, Hebei province, China, 2010-2020
YUN Ling, WANG Fu-cai, ZHANG Ling
Abstract199)      PDF (621KB)(137)      
Objective To investigate the mosquito species composition, population density, and seasonal fluctuation in Tangshan, Hebei province, China, 2010-2020, and to provide a basis for the prevention and control of mosquitoes and mosquito-borne diseases in Tangshan. Methods Adult mosquito density of different species was monitored using the lamp-trapping method. The mosquito species composition, population density, and seasonal fluctuation were analyzed in different habitats. SPSS 25.0 software was used for data analysis. Differences in mosquito species composition were examined using the χ 2 test. Results A total of 24 039 adult mosquitoes were captured in Tangshan, 2010-2020, and the overall mosquito density was 1.91 mosquitoes/(lamp·h). The dominant species was Culex pipiens pallens, followed by Anopheles sinensis. The density of Cx. pipiens pallens[3.13 mosquitoes/(lamp·h)) and Cx. tritaeniorhynchus[0.01 mosquitoes/(lamp·h)] were highest in livestock sheds. The density of Aedes albopictus[0.02 mosquitoes/(lamp·h)] was highest in urban residential areas. The density of An. sinensis[0.04 mosquitoes/(lamp·h)] was highest in parks. Mosquito density in Tangshan generally decreased over the past 11 years, with a statistical difference across the years ( χ 2=109.306, P<0.001). The highest mosquito density was found in livestock sheds, followed by hospitals, rural houses, parks, and urban residential areas. There was a statistical difference in the composition of mosquito species between different habitats ( χ 2=349.301, P<0.001). The trends of mosquito density in different habitats all showed unimodal distribution, and mosquito activity peaked in July and August. Conclusion Cx. pipiens is the dominant mosquito species in Tangshan. Mosquito density generally decrease over the years and is highest in livestock sheds. Mosquito activity peak in July and August when effective mosquito-control measures should be implemented.
2022, 33 (3): 351-355.   doi: 10.11853/j.issn.1003.8280.2022.03.007
Epidemiological characteristics of hemorrhagic fever with renal syndrome and surveillance studies of host animal in Quzhou, Zhejiang province, China, 2006-2020
WANG Min, YANG Hui, YU Zhang-you, ZHONG Jian-yue, FANG Chun-fu, WU Shi-quan, GONG Zhen-yu
Abstract197)      PDF (951KB)(138)      
Objective To investigate the epidemiological characteristics of hemorrhagic fever with renal syndrome (HFRS) as well as the species composition and Hantavirus infection status of host animals in Quzhou, Zhejiang province, China, and to provide a reference for formulating scientific prevention and control measures. Methods The incidence data of HFRS in Quzhou from 2006 to 2020 were analyzed. The night snap-trapping method was used to capture small mammals to calculate the capture rate and analyze the species composition of small mammals. The lungs and blood of the small mammals were collected to detect Hantavirus antigen and antibody for information on hantavirus infection among the small mammals. The Chi-squared test was used to compare the rates. Results A total of 720 cases of HFRS were reported in Quzhou from 2006 to 2020, with an average annual incidence rate of 2.13/100 000. Of those, there were two deaths, with a fatality rate of 0.28%. The cases were mainly aged between 30 and 69 years, accounting for 92.08% of total cases. Farmers accounted for 80.14% of total cases. The male-to-female ratio was 2.35:1. The incidence of HFRS peaked during May to July and October to next January. The average annual incidence was highest in Kaihua county, which was 8.81/100 000. The indoor and outdoor capture rates of small mammals were 5.57% and 6.14%, respectively, showing a statistical difference ( χ 2=7.374, P=0.007). Rattus norvegicus was the dominant species indoors, accounting for 41.18%, and Apodemus agrarius was the dominant species outdoors, accounting for 62.97%. There was a statistical difference in the species composition of small mammals indoors and outdoors ( χ 2=1 343.773, P<0.001). The antigen-positive rate of Hantavirus averaged 2.42%, and differed statistically between different species of small mammals ( χ 2=17.260, P=0.004). The serum antibody-positive rate for Hantavirus averaged 6.71%, and differed statistically between different species of small mammals ( χ 2=32.923, P<0.001). Conclusion There is a high density of small mammals and a high infection rate of Hantavirus among these small mammals in Quzhou. Cases of HFRS are mainly middle-aged and elderly, with high proportions of males and farmers. Its incidence shows double peaks in summer and winter. It is still necessary to strengthen comprehensive control measures combining HFRS monitoring, rodent control, health education, and vaccination for prevention and control of HFRS.
2022, 33 (4): 480-484.   doi: 10.11853/j.issn.1003.8280.2022.04.007
Tabanus hypomacros: A suspected mechanical transmission vector of African swine fever virus in Dabie Mountain region of Jinzhai county, Anhui province in China
ZHANG Xiang, CHENG Rong-rong, LIU Lu-yao, SUN Meng, HONG Yu-hang, YANG Cong-shan, LIU Yan, YIN Zong-jun, XU Qian-ming
Abstract189)      PDF (1429KB)(262)      
Objective To investigate the role of blood-eating insects in the family Tabanidae in the spread of African swine fever virus (ASFV) in the Dabie Mountain region of Jinzhai county, Anhui province, China, and to provide evidence for the prevention and control of Africian swine fever in the region. Methods The insect trap method was used to collect wild horsefly in the Dabie Mountain region of Jinzhai county, Anhui province in September 2019. The collected horseflies were observed with a stereo microscope to preliminarily identify their species based on their morphological characteristics. The collected horseflies were separately ground and DNA was extracted using a tissue nucleic acid extraction kit and a virus nucleic acid extraction kit. Cytochrome c oxidase subunit Ⅰ (COⅠ) gene amplification and sequencing were performed on the tissue genome to identify the species of the horseflies. With the ASFV p72 gene primers published by World Organisation for Animal Health, the ASFV nucleic acid was amplified by PCR, followed by sequencing to detect the DNA of ASFV in the horsefly samples. Results A total of 24 horseflies were collected from three different locations. Through morphological observations and COⅠgene amplification and sequencing, the horseflies were identified as Tabanus hypomacros. Amplification with the ASFV p72 gene primers was positive for part of viral nucleic acid extraction samples, with an overall positive detection rate of ASFV of 45.83%. The product of the positive amplification with ASFV p72 primers was sequenced to be a 278 nt sequence. The phylogenetic analysis showed that the ASFV in the horsefly specimens and the epidemic ASFV strains in China were in the same evolutionary branch. Conclusion ASFV is found in wild horseflies in the Dabie Mountain region of Jinzhai county, Anhui province, and is highly homologous to the epidemic ASFV strains in China, indicating that T. hypomacros can be a potential mechanical transmission vector of ASFV.
2022, 33 (3): 326-330.   doi: 10.11853/j.issn.1003.8280.2022.03.002
A study of factors affecting the sensitivity of adult Culex pipiens pallens to pyrethroid insecticides
LI Wen-yu, ZHOU Xin-xin, LUN Xin-chang, MA De-long, LIN Ling-hong, SONG Xiu-ping, LU Liang, LIU Qi-yong, WANG Jun, WANG Chun-lan, MENG Feng-xia
Abstract157)      PDF (845KB)(164)      
Objective To study the factors affecting the sensitivity of adult Culex pipiens pallens to pyrethroid insecticides, and to provide evidence for the insecticide resistance surveillance and the control of adult Cx. pipiens pallens. Methods The WHO tube test was performed on laboratory Cx. pipiens pallens strains (the Beijing[BJ] strain, Beijing sensitive[BJS] strain, and Tianjin[TJ] strain) to evaluate the insecticide susceptibility of adult test mosquitoes to permethrin and deltamethrin under different conditions. Results In female adult mosquitoes, the sensitivity to permethrin was the BJ strain ≈ the BJS strain > the TJ strain (≈ meaning no significant difference in sensitivity between the two strains), and the median lethal concentrations (LC 50) were 0.258% (0.222%, 0.304%), 0.283% (0.239%, 0.334%), and 0.457% (0.413%, 0.508%), respectively. In male adult mosquitoes, the sensitivity to permethrin was the BJ strain > the BJS strain ≈ the TJ strain, and the LC 50 values were 0.174% (0.157%, 0.195%), 0.249% (0.213%, 0.290%), and 0.251% (0.205%, 0.294%), respectively. The sensitivity of female adult mosquitoes to deltamethrin was the BJ strain > the BJS strain ≈ the TJ strain, and the LC 50 values were 0.024% (0.021%, 0.028%), 0.080% (0.066%, 0.099%), and 0.098% (0.079%, 0.127%), respectively. The sensitivity of male adult mosquitoes to deltamethrin was the BJ strain ≈ the BJS strain, and the LC 50 values were 0.038% (0.032%, 0.449%) and 0.018% (0.011%, 0.034%), respectively. The knockdown resistance mutation rate was 15.96% in the BJ strain, while no mutation of the gene was detected in the BJS strain and TJ strain. Under laboratory conditions, the natural mortality of male adult Cx. pipiens pallens was higher than that of female mosquitoes at any age. Under the same conditions, male adult mosquitoes were more sensitive to the insecticides than female adult mosquitoes. The toxicity of deltamethrin was 3.5-10.8 times that of permethrin. Conclusion Age and sex can affect the insecticide susceptibility of adult mosquito populations. Therefore, when carrying out insecticide resistance monitoring or efficacy evaluation, test mosquitoes should be homogeneous.
2022, 33 (2): 171-176.   doi: 10.11853/j.issn.1003.8280.2022.02.002
Comparison of three Aedes albopictus density monitoring methods
MA De-zhen, SONG Wei, XU Yan, LIU Huan-yan
Abstract155)      PDF (715KB)(166)      
Objective To study the effects of three Aedes albopictus density monitoring methods. Methods One monitoring site each was selected in four types of habitats (urban residential areas, rural residential areas, waste collection stations, and parks) of Tai'an, Shandong province, China. The Breteau index (BI) method, Mosq-ovitrap (MOT) method, and double-layered mosquito net method were used to separately monitor the density of Ae. albopictus once each in the early, middle, and late periods of every month from April to November 2020. Differences in mosquito density were examined using Chi-squared test, and a Pearson correlation analysis was used to analyze the correlation between BI and mosq-ovitrap index (MOI). Results The average BI was 1.57, the average MOI was 6.22, and the average adult mosquitoes density by double-layer net method was 0.05 mosquito/net·h from April to November in 2020. The seasonal fluctuation trend of the three monitoring methods was basically the same, and the peak density was all in early August. Adult Ae. albopictus was detected by MOT method in early May, and Ae. albopictus was detected by BI method and double-layer net method in early July. There was a positive correlation between the BI and the MOI ( r=0.957, P<0.001), and there was a positive correlation between the MOI and the adult mosquitoes density by double-layer ( r=0.914, P<0.001), and there was a positive correlation between the BI and the adult mosquitoes density using double-layer net method ( r=0.934, P<0.001). the BI in waste collection station (5.16)>in rural residential area (3.10)>in urban residential area (0.11)>in park (0.00). the MOI of park (6.90)>urban residential area (6.82)>rural residential area (5.55)>waste collection station (4.84). The adult mosquitoes density by double-layer net method in waste collection station (mosquito/net·h) (0.32)>rural residential area (0.30)>park (0.22)>urban residential area (0.06). Conclusion The density index of Ae. albopictus monitored by the MOT method is relatively high, which can reflect the density level of Ae. albopictus at an earlier time to provide an earlier warning of mosquito-borne diseases in Tai'an city. The BI method and double-layer net method are suitable for density surveillance during the peak period of Ae. albopictus.
2022, 33 (3): 336-339.   doi: 10.11853/j.issn.1003.8280.2022.03.004
Morphological and molecular biological identification of Tyrophagus fanetzhangorum and T. putrescentiae
FAN Xiao-chen, LIU Lu-yao, FANG Yu, CHU Ling-miao, FENG Rui, LI Fei-yan, PAN Ruo-xi, WANG Shao-sheng, SUN En-tao
Abstract151)      PDF (3315KB)(80)      
Objective To identify Tyrophagus fanetzhangorum and T. putrescentiae by morphological and molecular methods. Methods Samples were collected from houses and stored products, and individual mites were selected for pure culture. The cultured adult mites were used to prepare slide specimens for morphological identification based on the taxonomic keys of Astigmata. Subsequently, genomic DNA was extracted from individual mites for the PCR amplification, and sequencing of mitochondrial cytochrome c oxidase subunit Ⅰ gene (CO Ⅰ). The resulting sequences were subjected to homology search using BLAST in NCBI. The CO Ⅰ sequences of T. fanetzhangorum and T. putrescentiae were aligned using Clustal Ⅹ 1.83. Sequence analysis was performed using MEGA Ⅹ, and a phylogenetic tree was constructed using the maximum likelihood method. Results The posterior 1/3 of the coxal plate Ⅱ of T. fanetzhangorum was concave, the inferior margin was "S" shaped, and the distal 2/3 of solenidion ω 1 on tarsus Ⅰ obviously widened. The coxal plate Ⅱ of T. putrescentiae was triangular, the inferior margin was straight or slightly concave, and the solenidion ω 1 on tarsus Ⅰ widened at the distal 1/4. The CO Ⅰ gene sequences of the isolated T. fanetzhangorum and T. putrescentiae showed >99.00% similarity with the CO Ⅰ gene sequences of T. fanetzhangorum and T. putrescentiae in GenBank. The phylogenetic tree showed that T. fanetzhangorum and T. putrescentiae clustered into a branch with a bootstrap value of 100%. Conclusion Identification of T. fanetzhangorum and T. putrescentiae can be performed based on morphological characteristics or molecular analysis of the COⅠ gene. The combination of morphological and molecular identification can improve the accuracy of the identification of closely related mite species.
2022, 33 (2): 277-280.   doi: 10.11853/j.issn.1003.8280.2022.02.021
Epidemiological characteristics of visceral leishmaniasis in Shanxi province, China, 2020
DAI Pei-fang, TIAN Xiao-dong, ZHAO Jun-ying, DONG Hai-yuan, CHENG Jing-xia
Abstract139)      PDF (573KB)(112)      
Objective To analyze the epidemiological characteristics of visceral leishmaniasis (VL) in Shanxi province, China in 2020, and to provide a reference for the effective prevention and control of VL. Methods The data of VL cases reported in Shanxi province in 2020 were collected from the National Disease Reporting Information System and were collated. Excel 2010 software was used to process and plot the data, and SPSS 18.0 software was used to perform one-way analysis of variance for comparison of the number of reported cases between different age groups in different regions. Results In 2020, a total of 87 VL cases were reported in 18 counties of 6 prefectures in Shanxi province, which increased by 85.11% compared with the year 2019, with an annual incidence rate of 0.23/100 000. The cases were mainly distributed in Yangquan (68 cases), Changzhi (7 cases), and Linfen (6 cases). The counties/districts with an annual incidence rate of >1/100 000 included Pingding county, suburban, urban, and mining districts of Yangquan, Xiangyuan county, and Daning county, and 80.46% of the total reported cases happened in these counties/districts. The peaks of reported cases were in May and July, respectively, and no cases were reported in December. Among the reported cases, 57 were males and 30 were females; 25.29% of them were aged <5 years, 32.18% aged 60 and older, and 26.44% aged 40-59; farmers (43.68%) were the main susceptible population, followed by scattered children (26.44%) and unemployed persons (12.64%). Conclusion In 2020, the prevalence of VL increased and the epidemic area became wider in Shanxi province. It is a serious situation and awareness, prevention, and control should be strengthened.
2022, 33 (3): 405-408.   doi: 10.11853/j.issn.1003.8280.2022.03.017
Spatial distribution characteristics and risk analysis of rodent density in Zhejiang province, 2021
LUO Ming-yu, WANG Jin-na, WU Yu-yan, LIU Qin-mei, LI Tian-qi, GONG Zhen-yu
Abstract137)      PDF (1358KB)(102)      
Objective To investigate temporal and spatial distribution characteristics of rodent density and aggregation areas in Zhejiang province of China in 2021, and to provide a scientific basis for rodent control and deratization and the prevention and treatment of rodent-borne diseases. Methods Statistical description was performed for the data of rodent density monitoring in each county (city/district) from January to November 2021, and the global and local spatial autocorrelation analyses were used to analyze the spatial distribution characteristics of rodent density. Results From January to November in 2021, a total of 380 208 effective rat traps were placed and 1 851 rodents were captured, with a mean rodent density of 0.49 per 100 traps (snap, cages or plates). Rodent density showed an increasing trend from January to November ( Z=3.913, P<0.001). Rodent density showed positive spatial autocorrelation within Zhejiang province, and there was a significant difference in Moran's I index among January, May, September, and November (all Z >1.96, P<0.05). The local spatial autocorrelation analysis showed that high-high aggregation areas were distributed in southern Zhejiang from January to November, which was consistent with the spatial distribution of the areas with high rodent density, and low-low aggregation areas were mainly distributed in northern and eastern Zhejiang. Conclusion The overall rodent density is at a relatively low level in Zhejiang province, but with a gradually increasing trend during the whole year of 2021. Rodent density in Zhejiang province shows geographical autocorrelation, and counties with a higher rodent density are mainly distributed in southern Zhejiang, and therefore, the risk of rodent-borne diseases should be concerned seriously in southern Zhejiang.
2022, 33 (4): 475-479.   doi: 10.11853/j.issn.1003.8280.2022.04.006
A study of population density, breeding habitat, and insecticide resistance of Aedes albopictus in Simao district, Pu'er, Yunnan province, China, 2020
MA Zhe, ZHENG Yu-ting, YANG Rui, XU Xiang, WEI Chun, YU Xiao-jun, YANG Chun-mei, JIANG Jin-yong
Abstract132)      PDF (628KB)(134)      
Objective To investigate the density, breeding habitat, and sensitivity to insecticides of Aedes albopictus in Simao district, Pu'er, Yunnan province, China, and to provide a scientific evidence for mosquito control. Methods The Breteau index (BI) method was used to investigate the breeding sites of Ae. albopictus and the density distribution of larvae in five settlements selected from different orientations in Simao district in August 2020. The collected larvae were reared to F1 generation in laboratory. The filter paper contact method was used to measure the sensitivity of adult mosquitoes to nine types of insecticides. The resistance degree was determined according to the mortality rate. Results A total of 618 water containers were identified in 281 households, and larvae were found in 138 water containers in 80 households. The BI, House index, and Container index were 49.11, 28.47%, and 22.33%, respectively. The highest BI was 71.67 and the lowest was 20.00. Statistically, among the 138 mosquito-positive water containers, 92 (66.67%) were household containers and 46 (33.33%) were disused containers. The positive rates of household containers and disused containers were 17.16% and 56.10%, respectively, with a statistical difference between them ( χ 2=62.157, P<0.001). The positive rates of indoor and outdoor containers were 11.16% and 47.87%, respectively, with a statistical difference between them as well ( χ 2=101.637, P<0.001). The outdoor places had a higher positive rate than the indoor places, with an odd ratio of 7.31. The investigation demonstrated that outdoor environments were the main breeding habitats for Ae. albopictus in Simao district. Meanwhile, the mortality rates of adult Ae. albopictus exposed to nine types of insecticides ranged from 6.56% to 99.38%. These Ae. albopictus mosquitoes showed resistance to beta-cypermethrin, deltamethrin, permethrin, and lambda-cyhalothrin, and suspected resistance to propoxur, fenitrothion, and malathion, while they were sensitive to bendiocarb and chlorpyrifos. Conclusion Ae. albopictus is broadly distributed in the core of Simao district and is of high density. Therefore, there is a potential risk of dengue fever. It has developed varying degrees of resistance to a variety of pyrethroid insecticides. It is necessary to strengthen the regular surveillance and control of Ae. albopictus population density and insecticide resistance and environmental management.
2022, 33 (3): 360-365.   doi: 10.11853/j.issn.1003.8280.2022.03.009
Status, hazards, and control strategy of primary invasive snails in China
YIN Ying-xuan, WU Yin-juan, HE Qing, HE Yong-xin, GAO Ruo-xi, LIU Qi-yong, LI Xue-rong
Abstract128)      PDF (722KB)(138)      
Cross-border exchanges have been increasing with the progress of globalization. Frequent human migration has contributed to tremendous development of economy and society, and at the same time brought in invasive alien species, causing considerable influences and hazards to native species, ecological environment, human health, and social economy in China. This paper summarizes the status, hazards, and control strategy of primary invasive snails in China, which provides a basis for the prevention and control of invasive alien snails.
2022, 33 (2): 305-312.   doi: 10.11853/j.issn.1003.8280.2022.02.027
Prevalence of rodent-borne pathogens in the southeast of Shanxi province, China
YU Juan, BIAN Xiang, XIE Bing, ZHAO Yong-bo, BI Ge-yue, DU Xia-yan, BI Li-fang, LI Dong-mei, RAO Hua-xiang
Abstract128)      PDF (758KB)(131)      
Objective To investigate the prevalence of Borrelia burgdorferi, Leptospira interrogans, Rickettsia typhi, Anaplasma phagocytophilum, Orientia tsutsugamushi, and Francisella tularensis in rodents in the southeast of Shanxi province, China, and to provide a scientific basis for the prevention and control of local natural focal diseases. Methods Seven sampling sites were selected in the southeastern region of Shanxi province in July 2020 and May 2021, and rodents were captured by the night trapping method. The spleen and kidney tissues of rodents were collected under aseptic conditions for detection of the above six pathogens by real-time polymerase chain reaction. The difference in pathogen detection rate among different species, sexes, tissues, and habitats of rodents was analyzed by the χ 2 test or Fisher's exact test. Results In total, 248 rodents from 8 species were captured, including Mus musculus, Apodemus agrarius, Niviventer confucianus, Caryomys inez, A. draco, Rattus tanezumi, Cricetulus triton, and A. peninsulae. Except A. peninsulae, four pathogens namely B. burgdorferi, L. interrogans, A. phagocytophilum, and O. tsutsugamushi were detected in the other 7 species of rodents, with detection rates of 21.77% (54/248), 5.24% (13/248), 1.21% (3/248), and 0.40% (1/248), respectively ( χ 2=200.097, P<0.001). R. typhi and F. tularensis were not detected. The detection rate of B. burgdorferi was the highest in the forest region and was statistical different between different habitats ( χ 2=17.906, P<0.001). B. burgdorferi was mainly detected in N. confucianus and A. agrarius, with a higher detection rate in kidney tissue than in spleen tissue ( χ 2=5.310, P=0.021). The detection rate of L. interrogans was the highest in the village, but was comparable between different habitats (Fisher's exact test, P=0.971). L. interrogans was mainly detected in R. tanezumi, with no statistical difference in the detection rate between spleen and kidney tissues ( χ 2=0.773, P=0.379). In addition, 11 rodents were found to have mixed infection with two pathogens. Conclusion B. burgdorferi and L. interrogans are the main pathogens prevalent in the rodents in southeastern Shanxi, which may have the possibility to cause human diseases. Therefore, corresponding prevention and control measures should be taken into consideration by relevant authorities.
2022, 33 (2): 211-215.   doi: 10.11853/j.issn.1003.8280.2022.02.008
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