ISSN 1003-8280 CN 10-1522/R 中国疾病预防控制中心 主办
Objective To study the resistance levels of mosquito larvae and adult insecticides of dengue transmission media in Dalian, Liaoning province, to provide scientific basis for the comprehensive prevention and control of Aedes albopictus. Methods The larvae and egg masses of Ae. albopictus were collected in the residential area of Dalian city from August to September 2017 and bred in the laboratory. The WHO recommended larvae dipping method and mosquito contact barrel method were employed in the bioassay. Results The resistance multiple of the larvae of Ae. albopictus to deltamethrin was 3.00, which was low resistance. The resistance multiples of the other four insecticides, such as β-cypermethrin, parathion, dichlorvos and permethrin were less than 3.00 and were sensitive. Aedes albopictus to malathion resistant population of adult primary (M), the mortality rate was 97.00%, of β-cypermethrin, permethrin and deltamethrin were sensitive group (S), mortality rates were 100%, 99.00%, and 98.00%. Conclusion Aedes albopictus in Dalian Liaoning province is low or sensitive to commonly used insecticides, which insecticides can be used for daily control of Ae. albopictus.
Objective To provide scientific guidance for the prevention and control of dengue fever and Zika disease outbreak by field control of Aedes albopictus which was carried out by vegetation barrier treatment and the methods of rapid and sustainable effective control of Ae. albopictus were explored. Methods During August-October, high efficient cypermethrin microcapsule suspension (barrier treatment residual spraying) and cypermethrin emulsion were sprayed on the vegetation of Ae. albopictus. The density of Ae. albopictus was monitored by human landing counts and was observed before and after application and analyzed by Excel 2007 software. Results The density reduction rate was 96.0%, 99.0%, 85.0%, 84.0%, 47.3%, and 3.0% respectively on the first day, and in the first through the fifth weeks, respectively, in the trial of cypermethrin microcapsule suspension. The densities of the Ae. albopictus were reduced by 83.0%, 77.0%, and -25.0% respectively on the first day, and in the first and the second week, respectively, in the trail of cypermethrin emulsion. Conclusion The application of vegetation barrier treatment can persist more than 3 weeks. It has the advantages of long lasting effect, resistance to rain water wash, time and labor savings, reduction of environmental pollution,and so on. This technique has a good application prospective to mitigate outbreak of Zika virus and other infectious diseases.
Objective To investigate on mosquito species of underground garage, and to make a preliminary research on the reason and tendency of them. Methods Gathered the mosquito larva from different kinds of underground garage in December of 2013 to November of 2014, then made some specimens of male mosquito genitalia after they were reared to adults. Results Culex pipiens molestus were the only species in the closed and small underground garage. Culex pipiens molestus accounted for 54.09%(119/220) of the Cx. pipiens complex in the closed and large underground garage, while Cx. pipiens pallens accounted for 27.27%(60/220). Culex pipiens pallens accounted for 54.23%(141/260) of the Cx. pipiens complex in the half-closed underground garage, while Cx. pipiens quinquefasciatus accounted for 35.77%(93/260). Conclusion Shanghai is located in the area with both Cx. pipiens pallens and Cx. pipiens quinquefasciatus, and it's complicated of mosquito species. It's necessary to monitor tightly in order to control the mosquito-borne infectious diseases.
Objective To explore the status of Culex pipiens molestus infestation in different types of underground garages of Shanghai downtown during winter and spring. Methods Larval sampling was conducted in 4 selected underground garages in Shanghai Huangpu district during December to June. Collected larvae were laboratory-reared until adult emergence, and then identification was attempted by male genitalia morphology. Results Of the 4 underground garages, the crude species composition of Cx. pipiens molestus reached 90.48%, especially in winter and early spring which reached 100% in some garages; as the season changes, this proportion of Cx. pipiens molestus decreased significantly (100% to 67.11%). The proportion of Cx. pipiens molestus in Garage D was significantly higher than the other 3 ones (χ2=24.579, 17.053, and 16.025; P < 0.01). The genitalia DV/D ratio of Cx. pipiens molestus from 4 garages varied significantly (χ2=-0.002, -0.021, 0.004, -0.027; F=19.586, P < 0.05); the maximum value ranged from 0.054 to 0.192. Conclusion Featured with high density of underground garage and high prevalence of underground Cx. pipiens molestus infestation, mosquito control still have a long way to go in downtown Shanghai.
Objective To explore the status of mosquito infestation in different types of underground garages in downtown Shanghai, and to analyze the causes and suitable countermeasures. Methods Randomly selecting 101 underground garages in Shanghai Huangpu district, conducting mosquito breeding status investigation during July and August, 2014. Results Of the 101 underground garages, the crude and adjusted positive breeding-rate was 35.64% and 39.13%, respectively, and the positive breeding-sites rate was 21.36%. Compared with the commercial building garages, the positive rate of underground collecting-wells(UCWs)in residential garage was significantly higher, and the positive rate of UCWs in bicycle garages are significantly higher than those in car garages. Comparison of different types of garages shows that the mosquito infestation in large-scale garages and multilayer ones are much higher (77.78% vs. 28.13%, χ2=11.434, P=0.001; 29.63% vs. 12.86%, χ2=6.740, P=0.009). Conclusion Featured with high density of underground garages and high degree of underground mosquito infestation, mosquito control still have a long way to go in downtown Shanghai. Compared to chemical mosquito-control measures, physical ones are recommended.
Objective To explore the status of mosquito infestation in different types of residential areas in downtown Shanghai, and to analyze the causes and countermeasures. Methods Selecting 3 mosquito monitoring sites from 3 different types of downtown neighborhoods in the same area, conduct 224 days’ continuous mosquito monitoring in CO2-light trapping method. Results Aedes albopictus is the predominant mosquito population in residential areas of downtown Shanghai (account for 72.35%), significantly higher than the density of sub-dominant Culex pipien pallens population (11.91 vs. 4.21/day·machine, P<0.05); Compared with the type of high-rise residential and old-fashioned villas environments, the old neighborhood environment faced more serious mosquito-infestation conditions, which has significantly higher mosquito density (total mosquito density, 28.91/day·machine, P<0.05), and much higher Ae. albopictus proportion (76.60%, P<0.05). Conclusion The situation of Ae. albopictus infestation in residential areas of downtown Shanghai is quite concerned, especially in old neighborhoods, whose living conditions and sanitary facilities are relatively poor. It is recommended that countermeasures should be taken to cope with the threat of Ae. albopictus-borne infectious disease in residential areas.
Objective To determine the resistance levels of wild populations of Anopheles sinensis to commonly used insecticides in Shanghai and Hunan. Methods The adult mosquito filter paper contact method recommend by WHO was used to determine the resistance levels of An. sinensis to deltamethrin, lambdacyhalothrin, permethrin, BPMC and fenitrothion in Qingpu, Baoshan, Jiading, Jinshan districts, Chongming county of Shanghai and Daoxian county of Hunan. Results Anopheles sinensis in six districts in Shanghai showed different resistance levels to five tested insecticides. High resistance to all five insecticides was detected in Baoshan, as well as to deltamethrin, permethrin and BPMC in Qingpu. Mosquitoes collected from Chongming showed the high resistance to deltamethrin and low resistance to lambdacyhalothrin. Low levels of resistance to lambdacyhalothrin and BPMC was also noted in mosquitoes originated from Jiading. High resistance to deltamethrin, lambdacyhalothrin, BPMC and fenitrothion was encountered in An. sinensis collected from Daoxian county of Hunan. Conclusion Anopheles sinensis has developed resistance to five tested insecticides in Shanghai and Hunan, and cross resistance among pyrethroid, organophosphate and carbamate may exist as revealed by correlation analysis.
Objective To explore the mosquito population dynamics in different seasons and mosquito circadian rhythm in different periods of a day. Methods Conduct more than 224-days'continuous monitoring of adult mosquitoes by CO2 trapping method to get the adult mosquito data in five different monitoring-sites in Shanghai People's Square and People's Park region. Results The monthly-distribution of mosquito species was significantly different in downtown Shanghai. As the most dominant mosquito species, Culex pipiens pallens reached an average density of 13.35 pcs/(day·site), and peaked in May and June (19.93 and 28.19 pcs/day·site, respectively); Aedes albopictus and Cx. tritaeniorhynchus both peaked in July (10.77 and 8.79 pcs/day·site, respectively). The circadian rhythm analysis showed that the largest proportion of mosquito appeared in the evening and early morning hours (20:00-08:00a.m.), followed by the nightfall hours (16:30-20:00), and Cx. pipiens pallens was the dominant species in the 2 period (78.14 and 66.05%, respectively); the daytime hours (08:00a.m.-16:30) had the least proportion, whose dominant species was Ae. albopictus (65.70%). Conclusion The monthly-distribution and circadian rhythm were different in mosquito population species and density, which can be attribute to the ecological difference of different mosquito species, but except that, we surmise the special urban environment and urban light pollution should also account for, and which should be confirmed by further study.
Objective To investigate the population dynamics, temporal distribution, and stinging indices of mosquito population in the downtown Shanghai, China. Methods Five mosquito?lmonitoring sites were set up in Shanghai Peoples Square and Peoples Park areas, where mosquitoes were frequently encountered. A 194-day continuous dynamic monitoring of adult mosquitoes was conducted by human landing catch. Results During the 194-day surveillance from late April to late October, 2012, a total of 1666 adult mosquitoes of 5 species and 3 genera were collected. The proportions of Aedes albopictus and Culex pipiens pallens were 71.1% and 27.7%, respectively. The high daily fluctuation of adult mosquitoes was observed. Most of the mosquitoes were captured during July to September, with a peak of 52 mosquitoes per day. Cx. pipiens pallens peaked in early June, and its population density was significantly higher than that of Ae. albopictus in May and June (P<0.05). Ae. albopictus peaked in late July, and its population density was significantly higher than that of Cx. pipiens pallens during July to September (P<0.05), so it was the predominant species during that period. Conclusion This is the first report on mosquito infestations in downtown area as the results of 194-day continuous surveillance based on human landing catch. The results suggested that routine mosquito monitoring methods have limitations and inaccuracy. Targeted and efficient measures with special focus on the two predominant mosquito species, Ae. albopictus and Cx. pipiens pallens, should be introduced into the prevention and control of mosquitoes in downtown Shanghai. Furthermore, the study suggested that the increasing suitable sites for overwintering mosquitoes are more likely to cause an earlier arrival of Cx. pipiens pallens peak in the studied areas.
Objective To establish the susceptibility baselines of Anopheles sinensis to commonly used insecticides. Methods The An. sinensis was provided by the National Institute of Parasitic Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, which was reared in the laboratory for more than 50 years without exposure to any pesticides. Impregnation method and filter paper contact method were used to determine the susceptibility to commonly used insecticides for the larvae and adults of An. sinensis. Results The susceptibility baselines of An. sinensis larvae to deltamethrin, beta-cypermethrin, permethrin, dichlorvos, BPMC, fenitrothion, and temephos were established by impregnation method; the results were described as y=13.0586+3.8987x, y=9.2950+2.1510x, y=10.3449+4.4594x, y=4.3319+8.7669x, y=11.3541+11.2014x, y=11.5447+6.9681x, and y=10.8033+4.6466x, respectively. The susceptibility baselines of adult An. sinensis to deltamethrin, beta?cypermethrin, permethrin, and BPMC were established by filter paper contact method; the results were described as y=12.5204+3.6871x, y=10.2596+3.0291x, y=8.4266+2.6610x, and y=13.8210+5.0963x, respectively. Conclusion The susceptibility baselines of An. sinensis larvae to seven insecticides and those of adult An. sinensis to four insecticides have been established. The results can be used as the reference for the discriminating doses for the larvae and adults of An. sinensis in China.