| Background Rats,mosquitoes,flies,and cockroaches are the main medical vectors in our country,they can cause severe disruption and bring seriously harm to people’s healthy and quality of life.For example,mosquitoes can bite and suck blood,rats have powerful ability for digging,flies and cockroaches contaminate plenty of food.The medical vectors can spread a serious of diseases,for instance,flies and cockroaches spread typhoid fever and dysentery by mechanical transmission,mosquitoes can spread dengue fever and malaria,rats can spread plague and epidemic hemorrhagic fever(EHF),and a third of the notifiable infectious diseases belong to vector-borne diseases in China.Aedes albopictus is the mian dengue vector.Ae.albopictus can cause the outbreak of dengue fever when there have dengue cases.Blattella germanica have the characters of fast-breeding,well-adjusted and fast-spreading,it gradually became the dominant species of cockroaches.The prevention and control of the medical vector is depand on the chemical control for a long time,nevertheless,the medical vector gradual develop insecticide resistance due to the long-time and frequent use of chemical pesticides,and the level of insecticide resistance tend to increase,which has become the problem of the prevention and control of the medical vector.Dapeng district is a new tourist area of Shenzhen city,and accommodate large numbers of visitors every year.The high density of medical vector not only influences the visitor satisfaction,but also can spread diseases to vistor.In order to scientific and reasonable prevent and control the medical vector,it is very important to master the basic situation of the medical vectors and the insecticide resistance of Ae.albopictus and B.germanica.Objective 1.Understanding the species,distribution,density and seasonal fluctuation of the medical vectors,and master the basic situation of the medical vector to supply reference to effective prevent and control the medical vector and vector-borne diseases in Dapeng district of Shenzhen city.2.Understanding the insecticide resistance of Ae.albopictus and B.germanica to guide the reasonable use of chemical pesticides and supply a scientific reference to effective prevent and control the medical vector.Methods 1.The surveillance of the main medical vectors was according to the“The National Plan for the Surveillance of Medical Vector(Trial)”and“The Method for Monitoring the Density of Medical Vector”.The squirrel-cage method was used to monitor rats.The ultraviolet lamp baited trap method,mosquito-oviposition trap method and Breteau index methods were used to monitor mosquitoes.The cage trapping method and sticky trapping method were used to monitor flies and cockroaches respectively.The classification and identification of the medical vector was base on“The Classification and Identification of important Medical Insects in China”.2.The larvae dipping method was used to research the insecticide resistance of Ae.albopictus to six commonly used insecticides.3.The residual film method was used to research the insecticide resistance of B.germanica to seven commonly used insecticides.The activities of glutathione S-transferase(GSTs),acetylcholinesterase(AChE),acid phosphatase(ACP),alkaline phosphatase(AKP),and superoxide dismutase(SOD)were researched between the field-collected and sensitive B.germanica by spectrophotometer,and explore the survelliance indices of the insecticide resistance by analyzing the connection between the activitives of enzymes and insecticide resistance in B.germanica.Results 1.A total of 559 small mammals were caught,with Suncus murinus being the dominant species accounting for 48.30%,followed by Rattus norvegicus accounting for 25.22%.The average density of small mammal was 7.25%,and the seasonal fluctuation was obvious(1.72%~11.93%),with the peak period from August to October.There were significant differences between the different types of habitats in the small mammal density(χ~2=55.84,P<0.05),the highest density(11.35%)was in the old houses.A total of 2019 mosquitoes were captured,with Culex pipiens quinquefasciatus being the dominant species accounting for86.13%,followed by Ae.albopictus accounting for 5.40%.The average density of mosquito was 0.78 per hour in a lamp.The growth and decline of the season throughout the year was a two peaks curve,with the peak in May and January.There were significant differences between the different types of habitats in the mosquito density(F=3.81,P<0.05),the highest density(1.18 per hour in a lamp)was in the residential area.The mosquito and oviposition positive index(MOI)was 6.33,and there were significant differences between the different types of habitats in the MOI(χ~2=15.39,P<0.05).The Breteau Index(BI),House Index(HI)and Container Index(CI)were 10.06,6.38 and 26.35 respectively.A total of 12460 flies were captured,with Chrysomya megacephala being the dominant species accounting for 87.87%,followed by Lucilia sericata accounting for 3.66%.The average density of fly was 70.79 individual per cage,with the peak in June(193.57 individual per cage).There were no significant differences between the different types of habitats in the fly density(F=2.15,P>0.05),the highest density(109.03 individual per cage)was in the residential area.A total of 15981 cockroaches were captured,with B.germanica being the dominant species accounting for 89.09%,followed by Periplaneta Americana accounting for 5.65%.The average density of cockroach was4.76 individual per sheet,with the peak in August(9.10 individual per sheet).There were significant differences between the different types of habitats in the cockroach density(F=16.46,P<0.05),the highest density(109.03 individual per sheet)was in the restaurant.2.Ae.albopictus from Dapeng district of Shenzhen city became low level resistance to deltamethrin,permethrin,propoxur,temephos and dichlorvos,middle level resistance to beta-cypermethrin,and the resistance ratio was 6.39,6.83,2.47,3.48,2.22 and 11.33 respectively.3.B.germanica from Dapeng district of Shenzhen city became low level resistance to beta-cypermethrin,propoxur,dichlorvos and chlorpyrifos,middle level resistance to permethrin and acephate,high level resistance to deltamethrin,and the resistance ratio was 3.10,2.36,2.74,3.67,5.61,6.90 and 10.34 respectively.The activities of AChE,GSTs and SOD in the B.germanica from Dapeng district of Shenzhen city were significantly higher than sensitive strain.Conclusions 1.The dominant medical vectors species in the Dapeng district of Shenzhen city were Rattus norvegicus,Culex pipiens quinquefasciatus,Chrysomyia megacephala and B.germanica respectively.The density of small mammal,fly and cockroach were relatively high,it should be strengthen the prevention and control of the medical vector.2.Ae.albopictus from Dapeng district became varying degrees resistance to commonly used insecticides,with middle level resistance to beta-cypermethrin.3.B.germanica from Dapeng district became varying degrees resistance to commonly used insecticides,with high level resistance to deltamethrin.AChE,GSTs and SOD were related to the insecticide resistance of B.germanica,and the relative activities of AChE,GSTs and SOD can be used to survelliance the insecticide resistance of B.germanica. |
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