Figure 1

The research sites of this study. These sites include Tibet Center for Disease Control and Prevention (Tibet CDC) (N29°39.682’, E91°07.433’), Longwangtan Park (N29°39.582′, E91°07.151′), Tibet Post Hotel (N29°39.164′, E91°07.398′), Gamagongsang Community (N29°29.307′, E91°08.872′), Xiashasu Community (N29°39.284′, E91°07.867′) and Jiacuo Community (N29°39.429′, E91°05.375′).