A modeling study of human infections with avian influenza A H7N9 virus in mainland China

• The avian influenza A H7N9 virus has an R0 of 1.582 for poultry-to-poultry transmission.
• Without intervention, the H7N9 virus will persist in poultry populations.
• The R0 of H7N9 is only 0.07 for human-to-human transmission.
• Human-to-human transmission of H7N9 is not sustainable.
• Intensive screening/culling of infected poultry will rapidly eliminate the H7N9 virus.

SummaryObjectivesSince February 2013, more than 400 laboratory-confirmed human cases of avian influenza A H7N9 infection have been reported in mainland China. Little is known of the dynamics of this novel virus in poultry and human populations, which is essential for developing effective long-term control strategies for this zoonosis. The aim of this study was to evaluate the impact of screening and culling of infected poultry on the evolution of the H7N9 epidemic.MethodsA mathematical model for transmission dynamics of avian influenza A H7N9 virus in human and poultry populations was constructed. Parameters in the model were estimated using publicly available nationwide surveillance data on animal and human infections.ResultsBy fitting a two-host model, it was shown that screening for H7N9 in poultry and culling could effectively decrease the number of new human H7N9 cases. Furthermore, the elimination of circulating H7N9 virus is possible if an intensive, but technically feasible, poultry screening and culling policy is adopted.ConclusionsScreening and culling infected poultry is a critical measure for preventing human H7N9 infections in the long term. This model may provide important insights for decision-making on a national intervention strategy for the long-term control of the H7N9 virus epidemic.