Surveillance results of two important vector mosquitoes in Tianshui, Gansu, China, 2017-2020
CHEN Qiu-mei1, WANG Re-qin1, WU Hai-xia2, ZHANG Tao1, MA Yan-dong1, JIE Dong-gang1, GUAN Bin1
1. Vector Control Division, Tianshui Center for Disease Control and Prevention, Tianshui, Gansu 741000, China; 2. State Key Laboratory of Infectious Disease Prevention and Control, WHO Collaborating Centre for Vector Surveillanceand Management, Department of Vector Biology and Control, National Institute for Communicable Disease Controland Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
Abstract：Objective To investigate the density distribution and seasonal variation of Culex tritaeniorhynchus and Aedes albopictus in different habitats in Tianshui, Gansu province, China, and to provide a scientific basis for the prevention and control of mosquitoes and related infectious diseases in Tianshui. Methods A 4-year investigation was performed for 5-7 habitats twice a month from 2017 to 2020. The light trapping method was used to monitor adult Culex mosquitoes, and the double-layered mosquito net method was used to monitor adult Aedes mosquitoes in 3 habitats. SPSS 21.0 software was used to perform the chi-square test, Welch’s ANOVA analysis, and median test for the data of different years, habitats, and months. Results A total of 19 659 female mosquitoes were captured from 2017 to 2020, among which there were 5 759 Cx. tritaeniorhynchus mosquitoes (accounting for 29.29%), and there was a significant difference in the constituent ratio of different mosquito populations in the four years (χ2=851.227, P<0.001). The 4-year mean mosquito density was 5.81 mosquitoes/light/night, with the highest density of 17.17 mosquitoes/light/night in August, and the density of Cx. tritaeniorhynchus in 2017 and 2018 was significantly higher than that in 2019 and 2020, while mosquito density in July, August, and September of 2017-2018 was significantly different from that in other months (χ2= 12.000, P=0.035). The density of Cx. tritaeniorhynchus was significantly correlated with the number of Japanese encephalitis (JE) cases in the 4 years (r=0.629, P<0.001). The highest density of Cx. tritaeniorhynchus was found in pigsties, i.e., 17.33 mosquitoes/light/night, while the highest density was observed in cattle sheds in 2017 and 2018 (with a high incidence rate of JE). The mean net trap index of Ae. albopictus was 4.10 mosquitoes/net/hour, and the highest net trap index was observed in August, with a significant difference in density across months (F=207.031, P=0.001). Ae. albopictus was found in all habitats monitored for 4 consecutive years, and the highest net trap index was observed at waste sites/construction sites, with a significant difference in the net trap index between different habitats (F=16.892, P=0.010). Conclusion Cattle sheds and pigsties are the dominant habitats of Cx. tritaeniorhynchus, and with the highest density in August of each year in Tianshui. Ae. albopictus is distributed in each habitat monitored in Tianshui, and waste sites/construction sites are important breeding sites for Ae. albopictus, with the peak density in July and August. It is necessary to strengthen the investigation of distribution and habitat of mosquito vector, and to control mosquito based on their ecological characteristics in Tianshui city, which could be more effectively prevent and control related mosquito-borne diseases.
2021, Vol. 32 
