ISSN 1003-8280 CN 10-1522/R 中国疾病预防控制中心 主办
Objective To observe the effect of different temperature on the different development stages and fecundity of Culex pipiens pallens thus to evaluate the transmission capacity during the epidemic season, in order to provide a theoretic foundation for mosquito control. Methods The changes at different development stages of mosquitoes(eggs, larvae, pupae) and gonotrophic cycle were observed at different temperatures at 10, 15, 20, 25, 30, 35, 40℃. The full developmental cycles were compared within different temperatures. Results All the stages of the mosquitoes were unable to grow at 40℃; the mosquitoes developed at 10, 15, 20, 25, 30, and 35℃, the development time were 80.87, 46.33, 31.07, 24.94, 17.11, and 14.41 d respectively. Conclusion The development time of Cx. pipiens pallens was shorter at higher temperatures. The optimal temperature for the mosquitoes to develop was between 25-30℃, higher or lower temperature suppressed the development of the mosquitoes.
Objective To identify Anopheles sinensis population density, growth trends and insecticide sensitivity. Methods Anopheles mosquitoes were collected by human landing catch and collecting mosquitoes inside cowsheds during endemic season. The WHO insecticide-susceptibility test was used. The rate of knockdown was calculated after 10, 15, 20, 30, 40, 50, 60 minutes after exposure. The mortality was scored 24 hours after exposure. Results From late June to early October in 2008, 322 An. sinensis were collected by human landing catch in bed nets semi-overnight. The biting rate was 1.61 bites per person per hour. A total of 886 An. sinensis were captured in cowsheds. The density was 147.66 mosquitoes per person per hour. The resistance of An. sinensis to deltamethrin and cyfluthrin were levels R and M, respectively. From late June to early October in 2009, 349 An. sinensis were caught in bed nets semi-overnight. The biting rate was 1.25 bites per person per hour. With 652 An. sinensis collected, the density was 108.67 mosquitoes per person per hour. The resistance of An. sinensis to deltamethrin and malathion were levels R and R, respectively. Conclusion An. sinesis is resistant to deltamethrin and initially resistance to cyfluthrin in Jiangsu province. The applied insecticide should be chosen when there is outbreak of malaria by using insecticide treated nets (ITNs) and indoor spraying of insecticide. Health education should be introduced to local people to improve protection from mosquitoes and minimize contact with mosquitoes.
【Abstract】 Objective To observe the sensitivity of Anopheles sinensis to deltamethrin and cyfluthrin in malaria epidemic areas of Jiangsu province. Methods The adult mosquito test kit was used in this study recommended by WHO. The quantity of adult mosquitoes knocked down by deltamethrin and cyfluthrin was counted after exposure 10 min, 15 min, 20 min, 30 min, 40 min, 50 min and 60 min, and its mortality after treatment for 24 h was recorded. Results The knock down rates of An.sinensis to deltamethrin in Xuyi, Sihong, Suining, and Yixing county (city) were 67.37%, 64.00%, 71.43%, and 78.40% at 60 min after treatment, respectively, and the mortalities at 24 h after treatment were 68.42%, 68.00%, 72.53% and 76.80%, respectively. The resistance level of the An.sinensis to deltamethrin in four areas investigated was evaluated as “R”. The knock down rate of An.sinensis to cyfluthrin were 84.13%, 91.76%, 89.80% and 100% at 60 min after treatment in Xuyi, Sihong, Suining, and Yixing county(city), respectively. The mortalities at 24 h after treatment were 85.71%, 91.76%, 93.88% and 100%, respectively. The resistance level of An.sinensis to cyfluthrin in Yixing area was assessed as “S”, and “M” level in other three counties. Conclusion An.sinensis has high resistance to deltamethrin and low resistance to cyfluthrin in parts of malaria epidemic areas. In order to prevent development of resistance, the integrated management measures should be taken in the future.
【Abstract】 Objective To compare the developmental duration and vector capacity of malaria transmission of Anopheles anthropophagus from Liaoning and Jiangsu on pre-mature stage. Methods In laboratory, An.anthropophagus from Liaoning and Jiangsu were reared in the same environment and infected artificially in vitro. The biological indexes such as hatchability, emergence rate, pupation rate, the positive rate of mosquito stomach and oocyst and sporozoite infection rate of salivary gland were observed, respectively. Results The average developmental duration of egg from Liaoning population and Jiangsu population were 3.66 d and 3.84 d, and the hatchibility of egg were 76.0% and 74.3%. That of larva were 6.67 d and 8.26 d and the pupation rates were 94.7% and 96.0%. That of pupa were 1.60 d and 1.72 d and the emergence rates were 97.2% and 98.6%. The positive rates of mosquito stomach and oocyst were 25.1% and 28.1%, and the sporozoite infection rates of mosquito salivary gland were 8.4% and 10.7%. Conclusion It was no significant difference statistically between the developmental duration of larva and vector capability of malaria transmission of An.anthropophagus from Liaoning and Jiangsu (P>0.05). Therefore, the surveillance of vector should be strengthened during malaria transmission period.
【Abstract】 Objective To develop a molecular technology to assay human blood index of Anopheline mosquito which could substitute for the traditional immunological method. Methods A pair of specific primer were designed according to the sequence of human rDNA, and the human blood in Anopheline mosquito was identified by polymerase chain reaction (PCR). Meanwhile, the DNA extracted from the blood of pig, cattle, goat, mouse and the mosquito without bloodsucking were detected to verify the specificity of the method. And the DNA extracted from the mosquitoes after its bloodsucking for different time (such as 1 h, 6 h, 12 h, 18 h, 24 h, 27 h, 30 h, 33 h, 36 h, 40 h, 44 h, 48 h) were detected to determine the sensitivity of the method. Results The specific PCR product (519 bp) was amplified from the DNA extracted from human blood. No specific PCR product was found either from the blood of other animals or from the mosquitoes without bloodsucking. The specific bands were produced from all the mosquitoes within bloodsucking for 24 h. After bloodsucking for 27 h, 30 h, 33 h and 36 h, only 4, 4, 2, 1 mosquito could produce specific bands in the total of 5 tested mosquitoes, respectively. No specific PCR product was amplified after feeding for 40 h. Logistic regression analysis indicated there was a negative correlation between the bloodsucking time and the quantity of positive mosquitoes detected by PCR after bloodsucking for 24-40 h (P<0.01). Conclusion The PCR method developed in this study could identify human blood in Anopheles sinensis within bloodsucking for 24 h accurately, which could replace the traditional immunological method.