[A survey of antibodies to arboviruses in residents in south-western part of Yunnan province].

In order to provide serological evidence for arbovirus infection in Yunnan province, 760 Samples of human sera collected from nine counties in south-western part of Yunnan province were examined for HI antibodies to 11 arboviral antigens. The viruses used in this experiment included 3 alphaviruses (MAY, VEE and CHIK) and 8 flaviviruses (JE, MVE, KUN, DEN3, DEN4, KFD, LGT and POW). 275 samples were found positive for HI antibodies to alphaviruses (36.2%) and 189 of them (68.7%) reacted with MAY virus, 61 (22.2%) with CHIK. The GMT of HI titers for VEE, MAY and Chik were 164.4, 94.5 and 66.7, respectively. 588 samples of sera (77.4%) were found positive for HI antibodies to flaviviruses. The positive HI antibody rates were as follows: JE, 27.9%; DEN, 36.6%; KFD, 22.2%; MVE, 22.1%; KUN, 18.7%; POW, 8.8% and LGT, 7.9%, respectively. Its average GMT was 356, and the antibody titers of 403 samples of sera were higher than 1/640. Cross reactions among viruses, especially flaviviruses, were usually found by HI test, and superinfections were present. In addition to the existence of JE and DEN viruses the results clearly showed that many Kinds of arboviruses might exist in Yunan Province.