Recruitment and sampling
In each province, project investigators provided a two-day training workshop for study staff from local provincial and city-level Centres for Disease Control and Prevention who spoke the local language and were familiar with the local community. This included a unit on the ethical conduct of human subject research, an in-depth review of the study design and objectives, and comprehensive information on the implementation of observational research, semistructured interviews and notetaking within the context of this study.
Participants were identified through key informants and the snowball sampling method because the population size at selected sites and the people who had high-risk contacts with live animals were difficult to elucidate.22 Starting with the key informants, we asked each participant to suggest people who met the inclusion criteria and who might be interested in participating in this study; we then contacted the referrals for potential participation in our study. Local study staff visited potential participants and provided these individuals with the participant information sheet to introduce them to the study. We aimed to obtain a minimum sample size of 20 participants from each of the three provinces, for a total sample size of over 60 participants. At least two field observations of local markets and household environments were conducted at each study site, for a total of 18 observations at a minimum.
Participation in the study was strictly voluntary. Study staff reviewed the information sheet with potential participants and explained the details of the study. This included the voluntary nature of participation, inclusion and exclusion criteria, study implementation processes (e.g. that the interview would be audio-recorded), potential risks and benefits of participation, results sharing and that they could withdraw their participation at any time. It was also explained that an item as a token would be given as appreciation for their participation, which was identified by the study team and appropriate for the context of the study sites.
Figure 1  Coding themes, subthemes and analysis framework
Figure 2  Nine study sites in the Yunnan, Guangxi and Guangdong Provinces, Southern China