In 1 year, traders visited approximately 75 % of all villages in the modeled area. The mechanism by which traders may participate to the spread of avian influenza viruses has been described in previous studies (Fournie et al., 2012; Paul et al., 2013). Briefly, the H5N1 virus can easily be transported from one farm to another along a trader’s daily route through direct contact between transported poultry and poultry on visited households (potentially infected excretions or mucus may fall from cages to the ground).