Investigation On Dengue Virus Serum Antibody Of Healthy Residents And Preliminary Analysis Of Aedes Albopictus RDNA-ITS2Sequence In The Southwestern Yunnan

Objectives: To assess the dengue prevalence situation by investigating fordengue fever serology of healthy population in the southwestern Yunnan border areas,which provides the effective dengue fever prevention and control rmeasurments;and to reveal the characteristics of the mosquito gene polymorphism by comparingdifferent geographic strains of Ae.albopictus rDNA-ITS2sequence.Methods：(1)Dengue virus serum antibody detection,Serum were collected fromthe healthy residents and dengue virus antibody IgG was tested by the indirectenzyme-linked immuno-sorbet assay;(2) Ae.albopictus rDNA-ITS2sequenceanalysis,the three different geographic strains of Ae. albopictus were collected fromMengla, Jinghong and Simao,and mosquitoes DNA were extracted to be amplified byPCR, and its sequence differences were analyzed.Results:(1) Total of2547healthy human serum samples were detected from13border counties, of those195positive serum dengue virus IgG antibodies (7.66%),and the positive rate of antibody-positive from Ruili,Gengma,Mengla and Menghaiwere respectively17.50%,27.82%,11.50%,10.50%were higher than others, therewas statistically significant between the two-age groups, Mengla (χ~2=17.735, P<0.05) and Luxi (χ~2=4.714, P <0.05）, by comparing the positive serum denguevirus IgG antibodies of Sino-Myanmar areas (Ruili, Wanding, Yingjiang, Luxi,longchuan,Tengchong,Gengma,Menglian, Lancang, Jinping,Fugong) to those of Sino-laos areas （Menghai, Mengla)， Sino-Myanmar areas(11%) was higher thanSino-laos（7.03%）（χ~2=8.280，P＜0.05）; total of1060healthy human serum sampleswere detected from5non-border areas, of those53positive serum dengue virus IgGantibodies (5.00%),there was statistically significant between Jinggu and Fengqing（χ~2=6.185， P＜0.05）, and,the serum DF antibody positive rate in Jinggu(7.83%)was higher than Fengqing(2.22%) and Jinping(2.61%), There also wasdifferent between border areas and non border areas（χ~2=16.914，P＜0.05），and thepositive rate of dengue serum antibodies was higher in border areas than those innon-border areas.(2) Ae. albopictus rDNA-ITS2sequencing results, among MenglaJinghong and Simao, only4from Simao and Jinghong (2for each) got the sequences,there some differences of the rDNA-ITS2gene sequences existed between Simao andJinghong samples, the rDNA-ITS2including single nucleotide and transversions,five C-T transitions, two A-C and two A-T transversions within489bps; the samegeographical strain from Jinghong，there were three sites of point mutations，G-C,C-T and T-A, while the Simao strains of two samples had the A-T and T-Atransversions.Conclusions： There has been previous and recent silent infection caused bydengue virus among the population in the southwestern Yunnan border areas,In spiteof high dengue infection rate in the border areas, now there has been no trend ofspreading from border to inland. The results suggest that surveillance, heath educationknowledges of prevention and control of dengue fever should be strengthened in theborder areas; rDNA-ITS2of Ae. albopictus from different geographic presented genepolymorphism.