Chadsuthi Sudarat, Wichapeng Surapa
Department of Physics, Research Center for Academic Excellence in Applied Physics, Faculty of Science, Naresuan University, Phitsanulok 65000, Thailand.
Department of Physics, Faculty of Science, Naresuan University, Phitsanulok 65000, Thailand.
Comput Math Methods Med. 2018 Jun 3;2018:5168931. doi: 10.1155/2018/5168931. eCollection 2018.
Hand, foot, and mouth disease (HFMD) has spread widely in a continuing endemic in Thailand. There are no specific vaccines or antiviral treatments available that specifically target HFMD. Indirect transmission via free-living viruses from the environment may influence 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 effect of indirect transmission from contaminated environments and the impact of asymptomatic individuals. By fitting our model to reported data on hospitalized individuals of HFMD endemic in Bangkok, Thailand, 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 findings suggest that cleaning the environment frequently and healthcare precautions which include the reduction of direct transmission rates should be promoted as effective control strategies for preventing the HFMD spread.
手足口病（HFMD）在泰国持续流行，已广泛传播。目前尚无专门针对手足口病的特异性疫苗或抗病毒治疗方法。环境中自由生存的病毒通过间接传播可能会影响手足口病感染，因为该病毒能在环境中长时间存活。在本研究中，我们提出了一种新的数学模型，以研究来自受污染环境的间接传播的影响以及无症状个体的影响。通过将我们的模型与2016年泰国曼谷手足口病流行期间住院患者的报告数据进行拟合，基本再生数估计为1.441，这表明在当前条件下该疾病将持续存在。数值模拟表明，无症状个体的直接传播和自由生存病毒的间接传播是导致手足口病新感染的重要因素。敏感性分析表明，基本再生数对手无症状和有症状亚组的传播率以及间接传播敏感。我们的研究结果表明，应提倡经常清洁环境以及采取包括降低直接传播率在内的医疗预防措施，作为预防手足口病传播的有效控制策略。
