The study was approved by the Department of Agriculture, Fisheries and Conservation, HKSAR; and Committee on the Use of Live Animals in Teaching and Research, The University of Hong Kong. Bats from 14 different locations in rural areas of Hong Kong, including water tunnels, closed mines, sea caves and forested areas, were captured over a 36-month period. Anal swabs were collected by an experienced veterinary surgeon, and kept in viral transport medium at 4uC before processing.