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 master the condition of rodent population distribution, seasonal fluctuation, rodent density for different habitats, and to provide a basis for developing rodent control strategies. Methods The rodents density was investigated by night trapping. Two types of monitoring points were chosen in town, one in residential and the other in special industry. Two types of monitoring points chosen in village were the rural and outside. Results Totally 1 059 319 traps were placed, 1 009 744 were effective, and 18 929 rodents were captured in Liaoning province from 2006 to 2015, the average rodent density was 1.87%. The density of rodents was lower in city(1.15%) than village(2.69%), and the highest was outside the village(3.39%), followed by inside the village(1.97%), special industry(1.32%) and residential community(0.97%). The density of rodents inside the village, in special industry and residential community were decreased, but that outside the village increased. Rattus norvegicus was predominant species in Liaoning province. The rodent constituent of R. norvegicus decreased, the rodent constituent of Apodemus agrarius and Mus musculus increased, the rodent constituent of Cricetulus barabensis and Tscherskia triton remained stable. In different habitats, R. norvegicus was predominant species inside the village, in special industry and residential community, Ap. agrarius was predominant species outside the village. The rodent constituent of R. norvegicus decreased in all those different habitats, M. musculus increased, Ap. agrarius outside the village increased, C. hamster and T. triton remained stable. Conclusion The density of rodents totally deceased from 2006 to 2015, but increased in recent years. The density of rodents was lower in city than village, the prevention and control for rodent density should focus on the rural areas. In different habitats,the rodent constituent of R. norvegicus decreased, M. musculus increased, Ap. agrarius outside the village increased. According to their characteristics of different habitats, comprehensive prevention measures should be taken to reduce the rodent density, for the purpose of controlling rodent-borne diseases.

Objective To investigate the population composition and seasonality of rodents and their density in different habitats in Liaoning province, China, and to provide a scientific reference for developing rodent control strategies. Methods Two types of monitoring points were chosen in cities (and towns), one type in residential area and the other in special industrial area. Additionally, two types of monitoring points were chosen in rural areas, one type in villages and the other out of villages. The density of rodents was monitored by night trapping. Results Totally 506 806 traps were set up in Liaoning province from 2009 to 2013. There were 485 792 effective traps, which captured 7548 rodents. The average density of rodents was estimated to be 1.55%, with a higher level in villages (2.25%) than in cities (0.93%). The density of rodents was highest in natural villages (2.25%), followed by special industrial areas (1.09%) and residential areas (0.78%) in cities. Seasonal fluctuations of rodent density in total, individual years, or different habitats followed a double-peak curve. Two peaks of rodent density occurred in April to May and in September to October, respectively. Rattus norvegicus was the dominant species of rodents in Liaoning province. Conclusion The density of commensal rodents in Liaoning province showed a slightly increasing trend from 2009 to 2013. Seasonality of rodent density followed a double-peak curve. The control of rodent density should focus on rural areas. According to their characteristics of seasonal fluctuations, comprehensive preventive measures should be taken to reduce the density of rodents in the two peak periods, in order to control rodent-borne diseases.

Objective To investigate the trends of Culex tritaeniorhynchus population dynamics in Liaoning province and to confirm that whether they carry Japanese encephalitis(JE)or not, which can support a scientific basis for establishing the strategy of prevention and control of Japanese encephalitis virus. Methods Culex tritaeniorhynchus, captureusing mosquito-lured lamp in 14 cities of Liaoning province during 2006-2013, were used to investigate the population composition and distribution and seasonality. Results Populations of Cx. tritaeniorhynchus in Liaoning province are mainly distributed in three cities, Dandong, Dalian and Panjin city, Dandong which has the highest distribution, the ratio of Culex is 78.43%, and the highest density is up to 780.20 Culex/(equipment·h) in 2007. In addition, Cx. tritaeniorhynchus were captured in Dalian, Panjin, Yingkou, Huludao and Jinzhou cities in different months. The highest density of Culex is appeared in September.Conclusion Culex mainly distributed in paddy growing areas of coastal cities in Liaoning province, including Dandong, Dalian, Panjin and Huludao;the most serious areas is Dandong city with the highest density and highest viral infection. In Lioaoning provience, there was a coincidence of early populations, high density and high JE infection. This phenomenon proves there is a relationship of Culex population trends and morbidity of JE, therefore, investigating the incidence of JE and the trends of Culex could not be ignored.

Objective To investigate the resistance of malaria vector Anopheles to five insecticides in Liaoning province, China and to provide a basis for prevention and control strategies. Methods The filter paper contact method for adult mosquitoes, as recommended by WHO, was used to measure the mortality of malaria vector Anopheles and its susceptibility to five insecticides. Results Malaria vector Anopheles had resistance to five insecticides in Donggang city of Dandong and Beizhen city of Jinzhou, and the lowest mortality was only 16.7%. In Dandong, Tieling, and Jinzhou, Anopheles mosquitoes also developed varying degrees of resistance to 4% DDT, 0.05% deltamethrin, and 0.05% beta-cypermethrin, with the highest mortality of 97.4%. The 0.1% propoxur had good lethal effect on malaria vector Anopheles in Zhen'an district of Dandong and Kaiyuan city of Tieling, and 0.75% permethrin had good lethal effect on Anopheles mosquitoes in the Zhen'an district, all leading to a mosquito mortality of 100%. Conclusion In some areas of Liaoning province, malaria vector Anopheles maintains high resistance to DDT, and it also has varying degrees of resistance to beta-cypermethrin and deltamethrin. Thus, it is necessary to properly use the insecticides for delaying the development of insecticide resistance. Malaria vector Anopheles is relatively sensitive to propoxur and permethrin, so the two can be applied as main insecticides for Anopheles control at present.

Objective To investigate the types and distribution profiles of arboviruses at the riverside of Yalu River in Dandong, Liaoning province, China. Methods Mosquito samples were collected with mosquito lamps and then used for virus isolation by tissue culture. The obtained virus isolates were identified by serological and molecular biological methods. Results A total of 3359 mosquitoes (3 species, 3 genera) were collected from 6 sites at the riverside of Yalu River in July 2007. Eleven virus strains were isolated from the mosquito samples. Of the 11 strains, 5 were identified as Banna Virus (BAV), 3 were identified as Orbivirus, and 3 needed further identification. Based on the results of sequence analysis, the 5 BAV strains shared high homology in terms of the 12th segment, with nucleotide and amino acid homologies of 92.1%-99.8% and 92.8%-99.5%, respectively, and were highly homologous with those from Beijing and Yunnan province, China, exhibiting nucleotide and amino acid homologies of 91.3%-98.7% and 90.8%-100%, respectively. Phylogenetic analysis showed that the 5 BAV strains and the BAV strains isolated from Beijing and Yunnan province were located in the same branch. Conclusion BAV and Orbivirus were first isolated at the riverside of Yalu River in Dandong, Liaoning province, China, and the newly isolated 5 BAV strains have a close phylogenetic association with BAV strains isolated from Beijing and Yunnan province, China.

Objective The susceptibility of the larvae and adult mosquitoes of Culex tritaeniorhynchus in Donggang city, Liaoning province to commonly used insecticides was evaluated to determine their insecticidal resistance and identify the relationship between the resistance levels of the larvae and adult mosquitoes, providing the basis for chemical control of the mosquitoes.  Methods A large number of adult Cx. tritaeniorhynchus were collected outdoors in the peak seasons to obtain the first filial generation, fed with the blood of mice, for testing. The impregnation method and the contact exposure method, as recommended by the WHO, were  employed  to  determine  the  susceptibility  of  the  larvae  and  adult  mosquitoes  of Cx. tritaeniorhynchus to commonly used insecticides, respectively, for calculating the LC50 and the corresponding 95% confidence limits (95%CI) for the larvae, and the knockdown rate and mortality of the adult mosquitoes for comparison of their resistance levels to commonly used insecticides. Results The LC50 and the corresponding 95%CI of deltamethrin, beta?cypermethrin, and permethrin for Cx. tritaeniorhynchus larvae were 0.002 098 (0.001 575- 0.002 866), 0.013 80 (0.011 43-0.016 64) and 0.016 51 (0.014 00-0.019 49) mg/L, respectively; the LC50 and the corresponding 95%CI of dichlorvos, temephos and fenitrothion were 25.3479 (21.4949-28.3828), 48.3763 (31.7172-92.4088) and 0.1685 (0.1085-0.2679) mg/L, respectively; the LC50 and the corresponding 95%CI of BPMC were 0.2874 (0.1803-0.4268) mg/L. Compared to the susceptible strains reported in previous literature, the larvae of Cx. tritaeniorhynchus had the resistance coefficients of 5.3, 2.3 and 3.3 to deltamethrin, beta?cypermethrin and permethrin, respectively, and 396.1, 40 313.6 and 34.0 to dichlorvos, temephos and fenitrothion, respectively; the mortality rates of the adult Cx. tritaeniorhynchus exposed to 0.05% deltamethrin (contact for 1 h), 0.25% permethrin (3 h), and 1% fenitrothion (1 h) beyond 24 h were 15.9%, 27.7% and 8.2%, respectively. Conclusion The larvae of Cx. tritaeniorhynchus in Donggang city, Liaoning province developed high resistance to organophosphate and low resistance to pyrethroids. However, the adult mosquitoes were highly resistant to deltamethrin, permethrin, and fenitrothion. The resistance levels of the larvae and adult Cx. tritaeniorhynchus to pyrethroids were inconsistent.

【Abstract】 Objective To ascertain the breeding and distribution situation of Aedes albopictus in the northern of Liaoning province. Methods Mosquito larvae were investigated by container investigation method and ovum-trap method, and adult mosquito by man-trap method. Results Ae.albopictus only distributed in Chaoyang city. The container index of mosquito larvae was 13.54%. The index of houses was 3.24%. The index of Breaut was 0.53. The highest destiny of mosquitoes was 11.0 /man· hour. Conclusion Ae.albopictus only distributes in Chaoyang city and Dalian city. The northwest boundary of the distribution is in Chaoyang city. Ae.albopictus in Liaoning province mainly comes from other provinces. Whether Ae.albopictus can overwinter in Liaoning or not need to be studied further.