The Yunnan, Guangxi and Guangdong provinces in southern China were selected for this study because of their historical importance in the origin of emerging infectious diseases,16 diverse wildlife population within protected forests17 and intensive wildlife farming and trade activities.18 Three sites in rural areas were identified in each province where our previous research had found numerous bat and rodent populations harbouring viruses with pathogenic potential for humans, at sites close to human communities.19–21