Background Hand Foot and Mouth Disease (HFMD) is a highly contagious disease and has become an epidemic in many Asian-Pacific countries, including Thailand. With such epidemic characteristics and potential economic impact, HFMD is a significant public health issue. Comprehensive modelling of HFMD’s epidemic dynamics can be useful in understanding and predicting any potential outbreak of it, and manage its impact efficiently and effectively. Generally, the transmission dynamics of infectious diseases vary across geolocations due to different socio-economic situations, demography, and people’s lifestyles. However, there is no nation-wide and comprehensive (i.e., the inclusion of reinfections in the model) modelling of HFDM dynamics in Thailand. We aim to develop a nation-wide comprehensive modelling of HFMD’s epidemic dynamics and understand the reinfection cases in Thailand.
Methods We have formulated Susceptible - Exposed - Infectious - Recovered - Susceptible (SEIRS) epidemiological model with dynamic vitals, including reinfections, to investigate the transmission of this disease in Thailand. We also introduced periodic seasonality to model the seasonal effect. According to the model, the spread of this disease is uneven throughout the provinces in Thailand. So, we have grouped the provinces into three clusters (i.e., highly, moderately and least affected provinces) using K-means unsupervised machine learning algorithm for better estimation of the parameters and fitting the model. We collected data from three local hospitals in Thailand to analyze the reinfection cases.
Results The result from the analysis of HFMD recorded cases from three hospital (years 2012 to 2016) shows that 11% (approximately) are reinfections. By fitting the model with HFMD confirmed cases (years 2011 to 2019) and considering the reinfections, the basic reproductive number (R0) was estimated to be 2.643, 1.91 and 3.246 for three clustered provinces.
Conclusion In a conclusion, it is found that HFMD is re-infectious disease in Thailand. It is also found that the spread of HFMD is not uniform across the provinces in Thailand. The basic reproductive number R 0 was estimated to be greater than 1 for all the three clusters. This indicates that under the same social and environmental condition, this disease will persist in coming years.