ISSN 1003-8280 CN 10-1522/R 中国疾病预防控制中心 主办
Objective To test the resistance to pyriproxyfen in dengue vectors Aedes aegypti and Ae. albopictus and observe the mortality pattern of mosquitoes at various concentrations in Jinghong city, Yunnan province, so as to provide evidence for dengue vectors control and resistance management. Methods Aedes larvae were collected from Dengue epidemic areas in Jinghong from October to November, 2015. WHO recommended methods for insect growth regulators was carried out on the 3rd instar larvae collected. The resistance ratio (RR) was calculated by comparing half inhibition of emergence concentration (IE50) of the tested wild population with the susceptible reference strain. Additionally, the mortality pattern of dengue vectors exposed to pyriproxyfen was analyzed by observing daily stage-specific mortality at various concentrations. Results The IE50s of Ae. aegypti and Ae. albopictus in Jinghong city were 0.024 47 (0.022 09-0.027 07) and 0.135 20 (0.117 10-0.156 60) μg/L. There was 13.44-fold resistance in Ae. albopictus and 0.85-fold resistance in Ae. aegypti to pyriproxyfen compared with the susceptible strains respectively. Aedes albopictus was also 5.53-fold more tolerant to pyriproxyfen than Ae. aegypti in Jinghong city. For the dead individuals, most of them died at 4-6 d after exposure to pyriproxyfen, and the peak of death for susceptible Ae. aegypti and Ae. albopictus were at 4-5 d and 4 d respectively. A wider range of death peak was observed for Jinghong population of Ae. aegypti and Ae. albopictus, which was at 4-6 d. At low concentrations, most of the dead were deformed adults and mosquitoes not completely separated from the pupae. For the susceptible reference strain, dead pupae began to occur steadily when the mortality was over 60%, and the proportion increased as the concentration went up. However, the mortality of pupae was fluctuating in Jinghong population. Conclusion In Jinghong city, Ae. aegypti larvae was susceptible to pyriproxyfen. Considering this species is preferentially found in urban areas, pyriproxyfen is recommended to use in urban areas. Although Ae. albopictus larvae have developed moderate resistance to pyriproxyfen, this larvicide still can be used in alternatery with other insecticides to delay the resistance development. It proves that pyriproxyfen is highly efficient for mosquito control and resistance management in Jinghong city. Periodic resistance monitoring must be conducted to learn the variations of resistance level timely.
Objective To investigate the distribution profiles of mosquitoes and arboviruses in Xishuangbanna,Yunnan province, China, and to provide evidence for prevention and control of arbovirus diseases. Methods Mosquito samples were collected in Xishuangbanna and then used for virus isolation by cell culture. RT-PCR was used to identify arbovirus. Serum and cerebrospinal fluid samples were collected from fever patients, and the common encephalitis virus IgM antibodies were detected by ELISA. Results A total of 13 337 mosquitoes, belonging to 29 species and 5 genera, were collected. The main mosquitoes were Culex tritaeniorhynchus (79.98%, 10 667/13 337), followed by Anopheles sinensis (7.95%, 1060/13 337) and An. peditaeniatus (7.38%, 984/13 337). Several specific primers for Japanese encephalitis virus (JEV), Banna virus, alphavirus, and circovirus were used for PCR detection in 214 batches of mosquitoes, and no virus was isolated from the mosquitoes. Also, no virus was found in isolation using several types of cells. A total of 52 serum samples and 54 cerebrospinal fluid samples were collected from patients in acute stage by kits for encephalitis viruses and then subject to ELISA. There were 16 cases with JEV IgM, 4 cases with Herpes simplex virus IgM, 13 cases with mumps virus IgM, 3 cases with ECHO virus IgM, and 1 case with dengue virus IgM. Conclusion No JEV, BAV, and circovirus were detected from mosquitoes collected in Xishuangbanna,Yunnan province, China in 2011. However, serological results indicated that local fever patients were infected with several viruses such as JEV.
【Abstract】 Objective To explore the value of isozyme zymograms in the classification of blackflies and accumulate basic biochemical data for the study of phylogenesis. Methods EST isozymes of three blackfly species were studied by discontinuous PAGE techniques. Results Ten isozyme bands could be identified according to the electrophoresis zymograms. The differences of zymograms were significant between three blackfly species and each species had its own special zymogram. The main band among intraspecific individuals or between the larvae and pupae was alike, however, other enzyme bands were different. Conclusion EST isozyme zymograms could be used as one of the classification characteristics of blackflies.