| Objective:To investigate the species of dengue vectors ecological characteristics, their natrual dengue virus infected rate and the dengue fever antibody of healthy residents in Menglian and lancang county, bordering with Burma in Yunnan province, then provide effective measurements to prevent and control dengue fever.Methods:(1)Investigation of the species of dengue vector and the ecological characteristics from June to October of 2010, in the last ten days of each month, the habitant of breeding and population seasonal fluctuation of Aedes mosqutoes were investigated in three natural villages of Menglian and Lancang counties. For survey of Aedes larva, all larva and pupa were captured from the voious types of water containers indoor and outdoor, of them the 4 stage larvaes were dipped into absolute alcohol in 1.8ml vials, then classified, identified and noted; the density of Aedes larva was calculated by HI, CI, BI and Thousand person index. Survey of adults, Adult mosquitoes were captured by person-baited trap in the bamboo forest or the rubber forest during 5:30pm to 7:30pm, which were 200 meters away from house in the same village. The captured adults were brought back to the laboratory to classify, identify, count, record, deposite in liquid nitrogen with 1.8 ml frozen vials by different species, in order to extract and identify virus RNA from them. (2) Dengue virus infected rate in mosquitoes, virus RNA were extracted from mosquitoes specimens and detected and identified by RT-PCR, then dengue virus infected rate of different species mosquitoes were calculated respectively. (3) Serological DF antibody level of healthy residents, serum of healthy residents were collected in 3 natural villages, using ELISA (enzyme-linked immunosorbent absorption method) test to detect dengue IgG antibody.Results:(1) total of 3436 individual adult female mosquitoes of 22 species from 8 subgenus in 6 genus were collected. Of them 2050 individual Ar. subalbatus and 1162 individual Ae. albopictus, which accounted for 59.67% and 33.82% respectively, belonged to local predominant species in the daytime. From June to October, population density of adult Ae. albopictus in average month was 8.98 per person per hour. The biting rate in each month was 6.3,14.1,12.4,7.1 and 6 per person per hour respectively, its density peak was in July; the average of HI, CI,BI and index of thousand persons of 3 villages were respectively 19.3,5.84, 30.3,68.5;The habitants of breeding around village of Ae. albopictus were bamboo hole, jar and wasted tyres etc, which their positives were 34.1%, 27.5%,17.6% of total of collected positive water containers repectively.(2) Dengue virus infected rate in mosquitoes, total of 29 pools of Ae. albopictus (1162),4 pools of Ae.annandalei (138) and 49 pools of Ar. subalbatus (2050) were detected, of those 5 pools were positives in Flavivirus,among them 3 pools were Ae. albopictus and 2 ones were Ar. subalbatus. But no dengue virus in them was detected by using special primer of dengue virus.(3) DF antibodies level from serum of healthy residents, total 402 serum of healthy residents were collected and tested by ELISA, dengue antibody positive rate was 1.99%.Conclusions:(1) mosquito species in the daytime were complex in 2 border Counties, of those Ar. subalbatus and Ae. albopictus were local predominant species. Both of their population densities peaks were in July. Dengue virus was not detected from Ae. albopictus, but its density was higher and wide distribution extensive once occurred in imported dengue fever case, dengue would be transmitted in local. DF IgG level was low in the healthy residents, which hinted that DF epidemic had not occurred in the two border Counties. |
PDF Full Text Request