| BackgroundDengue fever is an acute infectious disease caused by the dengue virus. Infected with dengue virus can cause dengue fever,dengue haemorrhagic fever, dengue shock syndrome. The primary transmission vector of dengue fever are Aedes albopictus and Aedes aegypt. According to the World Health Organization reported, Dengue is epidemic in more than100countries and regions in Asia, Oceania, America, Africa and Africa, and it is especially serious in Southeast Asia, the Western Pacific and South Africa.About2.5billion people around the world are under the risk of Dengue virus infection. More than50million people are infected by the Dengue virus each year, and among them, half a million will develop DHF resulting in more than25,000deaths. Dengue is the second most serious vector-borne disease in the world just behind malaria in terms of morbidity and mortality. The first outbreak of DF in China was reported in Foshan county, Guangdong Province in1978. Since then, DF outbreaks were recorded in Hainan, Guangxi, Fujian and Zhejiang provinces, Between1990and2005, more than10,000cases of DF were reported in mainland China. In the recent years, Dengue epidemics in southern china have become more frequent and the epidemic area is expanding. DF has become a major public health problem in southern China, and effect its economic development. In Guangzhou City of Guangdong Province, because it is in the subtropical, the rainfall is adequate in summer and autumn, it is suitable for growth and reproduction of the Aedes albopictus. therefore the main vector of DF in Guangzhou area is Aedes albopictus.Aedes albopictus breeds in the settlements in and around. The female mosquito of Aedes albopictus is a impotant DF vevtor. It sucked the blood of human and attackd the human body more in the outdoors. The mosquito throughout the day are vampire, its biting acitivity is occurring in the morning and evening and easy to effect by emperature, humidity light and so on. Aedes albopictus transmits virus to human and/or animls by the bite of blood-sucking, its blood-sucking habits for different animals and the own performance of transmitting virus to different animals affect the transmission of the virus. Studies have show that Aedes albopictus sucks the blood of a variety of animal,and it has a characteristic of multiple blood-sucking. The study of Aedes albopictus blood-sucking habits can help us kown the possible host that transmits virus, provide guidelines for the prevention and control of mosquito-borne diseases. Foreign studies have shown that Aedes albopictus can sucked the blood of mammals and birds, the kind of its host animal are variety. But in the Guangzhou region of China, we don’t know the partial blood-sucking of Aedes albopictus to different animals, what is the possible host animal that save dengue virus? That also not clear. The study of Aedes albopictus blood-sucking habits can help us understand its blooding bias for aniamls and the possible host that transmits virus.Aedes albopictus is the major transmission vecto of dengue in China. It can provides the theory basic for the prevention and control of DF that survey the number of Aedes albopictus and monitor the density of Aedes albopictus. Dengue vector surveillance are including Aedes albopictus mosquito density monitoring and larvae density monitoring. Currently, the common monitoring methods of Aedes albopictus in our country are human-bait, UV light trapping, ovitrap oviposition, black-box method, but each of these methods are inadequate, it is required to find a high sensitivity and give a true and objective monitoring methods that can reflect the nature of Aedes albopictus mosquito density and population dynamics of change. In our study, we introduce the mosquito monitoring method, BG-Sentinel trap, that used commonly in foreign country, it was invented by the German Biogents company. A large number of foreign studies show that the efficacy of BG-Sentinel trap in monitoring mosquito is good. It can collects many kinds of mosquito, such as Aedes aegypti and Aedes albopictus, Polynesia Aedes, Culex quinquefasciatus, Culex pipiens. In our country, there is not report on the BG-Sentinel trap. In this study, we compared the efficacy of BG-Sentinel trap, CDC light trap, ovi-position trap for collection mosquito and explored its application prospects in monitoring adult mosquito in China.Objective1. Through the establishment of the PCR method identified the Aedes albopictus gastric blood source, study the blood-sucking habits of Aedes albopictus in Guangzhou region and determine the different animal vampire bias. understand the possible save host animals for Aedes albopictus transmission of dengue virus.2. In laboratory and field mosquito survey, comparing the effect of BG-Sentinel trap, CDC light trap, the oviposition trap, evaluating the effect of BG-Sentinel trap, and explore its monitoring role and application prospects in adult mosquito monitoring in China.Method1. Under laboratory conditions, the six animals (chickens, cats, dogs, pigeons, voles, mice) were placed in a small glass house or six kinds animal into a big glass house at the same time, then placed Aedes albopictus female mosquitoes that in the hunger for18h, after3hours, collected the blood-sucking mosquitoes. In field investigation, the blood-sucking female mosquitoes of Aedes albopictus collected by CDC light trap and BG-Sentinel trap, identify gastric blood sources of Aedes albopictus by established PCR system in the laboratory. Combination of laboratory and field results, determine the bloodsucking bias of Aedes albopictus for common animals.2. Under laboratory condition, the three kinds of traps were placed in the experimental room, then placed in mosquitoes (Aedes albopictus, Culex quinquefasciatu, Anopheles Sinensis) observed24h, collected mosquitoes captured by three traps, calculate the the number of captured mosquitoes. In the field survey, from July to December in2012, we selected four points in the Guangzhou area, laying three traps, then observed24h, collected mosquitoes captured by three traps, calculated the the number of captured mosquitoes. Compare the effect of three mosquito traps in the laboratory and field investigations.Result1. Investigation on blood-sucking habit of Aedes albopictus by polymerase chain reaction.1.1The bait effect of six animals for Aedes albopictus in different space.The average blood-sucking rate of Aedes albopictus for vole, chicken, cat, mice, dog, pigeons, were44.45%,38.27%,36.53%,35.70%,34.94%,24.75%respectively; Compare the average blood-sucking rate of Aedes albopictus for six animals, the blood-sucking rate of vole and pigeon are significant differences. The average blood-sucking rate for chicken, cat, dog, mice were higher than the pigeons, but the difference was not statistically significant.1.2The blood-sucking study of six animals for Aedes albopictus in different space. 437of Aedes albopictus were collected. The number of blood-sucking mosquitoes identified by PCR are119, which suck the chickens are54, pigeons are7, cats are27, dogs are11, mice are31, voles are21;30of Aedes albopictus with blood suck two or more kinds of animal blood. The bloodsucking rate differences of Aedes albopictus for six animals in same space are statistically significant.1.3The identification results of Aedes albopictus with full blood in field survey.A total of13Aedes albopictus with full blood were collected.The number of Aedes albopictus which suck dog blood are7, human blood are2, multiple vampire (cat and mouse) is1, the unknown blood source are3.2. Efficacy of three traps for collection of mosquitoes under laboratory and field conditions in Guangzhou, China.2.1Under laboratory conditions, Comparison the efficacy of three traps to capture Aedes albopictus, Culex quinquefasciatus, Anopheles sinensis.The BGS trap capture the Aedes albopictus, Culex quinquefasciatus number significantly higher than the CDC light trap and the oviposition. But for Anopheles sinensis the efficacy of CDC light is significantly higher than the BGS trap and the Mosq-ovitrap. BGS trap which capture Aedes albopictus and Culex quinquefasciatus female mosquitoes are superior to its capture of Aedes albopictus and Culex quinquefasciatus male mosquitoes. Comparison of three traps trapping Aedes albopictus, Culex quinquefasciatus, the Anopheles sinensis effect (three mosquitoes are200groups, female mosquitoes:male mosquitoes=1:1), the efficacy of BGS trap capture Aedes albopictus, Culex quinquefasciatus are significantly better than their capture Anopheles sinensis; the CDC light trap. The Mosq-ovitrap trap efficacy of Aedes albopictus was significantly superior to capture the effect of Culex pipiens and Anopheles sinensis.2.2In the field, Comparison the efficacy of three traps to capture Aedes albopictus, Culex quinquefasciatus, Anopheles sinensis.The BGS trap capture Aedes albopictus and Culex quinquefasciatus are significantly higher than the CDC light trap and Mosq-ovitrap trap; comparing the efficacy of three traps each month capture Aedes albopictus, Culex quinquefasciatus, BGS trap capture Aedes albopictus, Culex quinquefasciatus were significantly higher than the CDC light trap during the survey. Compare BGS trap capture Aedes albopictus number of female mosquitoes and male mosquitoes, the result shows that from July to October, BGS trap captureing the number of Aedes albopictus male mosquitoes are more than female mosquitoes, but in November,the result is opposite. Except the November, BGS trap capturing the number of female mosquitoes, male mosquitoes of the Culex are significantly higher than the CDC light trap.Conclusion1. Aedes albopictus have different levels of addicted to suck on common animals (chicken, voles, dogs, cats, pigeons, mice, etc.); it is verify that Aedes albopictus can suck the blood of chicken and pigeons and other birds blood, and have a characteristics of multiple bloodsucking.2. BGS trap trapping effect is remarkable. Monitoring of dengue vector Aedes albopictus application prospects are very brighting in China. |
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