The Modelling of Hand, Foot, and Mouth Disease in Contaminated Environments in Bangkok, Thailand

Hand, foot, and mouth disease (HFMD) has spread widely in a continuing endemic in Tailand. Tere are no specifc vaccines or antiviral treatments available that specifcally target HFMD. Indirect transmission via free-living viruses from the environment may infuence HFMD infections because the virus can survive for long periods in the environment. In this study, a new mathematical model is proposed to investigate the efect of indirect transmission from contaminated environments and the impact of asymptomatic individuals. By ftting our model to reported data on hospitalized individuals of HFMD endemic in Bangkok, Tailand, 2016, the basic reproduction number was estimated as 1.441, which suggests that the disease will remain under current conditions. Numerical simulations show that the direct transmission from asymptomatic individuals and indirect transmission via free-living viruses are important factors which contribute to new HFMD infections. Sensitivity analysis indicates that the basic reproduction number is sensitive to the transmission rate of asymptomatic and symptomatic subgroups and indirect transmission. Our fndings suggest that cleaning the environment frequently and healthcare precautions which include the reduction of direct transmission rates should be promoted as efective control strategies for preventing the HFMD spread.