Epidemiological and etiological characteristics of hand foot and mouth disease in reservoir and non-reservoir areas of three gorges area in China, 2009–2016

Objective To understand the epidemiological and pathogenic characteristics of hand foot and mouth disease (HFMD) and influence factors in the reservoir area and non-reservoir area in three gorges area, and provide evidence for the development of prevention and control strategies of HFMD.

Methods The HFMD surveillance data in these areas from 2009 to 2016 were collected from National Notifiable Infectious Disease Reporting Information System for a descriptive epidemiologic analysis, the results in reservoir area and non-reservoir area were compared.

Results From 2009 to 2016, the average annual morbidity rate of HFMD was 145.66/100 000, the proportion of severe cases was 0.19%, and the reported case fatality rate was 0.045% in reservoir area. The average annual morbidity rate of HFMD was 78.42/100 000, the proportion of severe cases was 0.28%, and the reported fatality rate was 0.05% in non-reservoir area. The reported morbidity rate of HFMD in reservoir area was higher than that in non-reservoir area. The proportion of severe cases in reservoir area was lower than that in non-reservoir area (χ²＝28.732, P＜0.01). There was no significant difference in reported case fatality rate between reservoir area and non-reservoir area (χ²＝0.876, P＝0.349). The pathogen causing severe cases was mainly EV71 (79.17%) in reservoir area, while the pathogen causing severe cases were mainly EV71 (47.37%) and other enterovirus (35.34%) in non-reservoir area. Other enteroviruses (37.83%) were more common in mild cases in reservoir area, while EV71 (41.19%) was more common in mild cases in non-reservoir area too.

Conclusion From 2009 to 2016, the reported morbidity rate of HFMD in reservoir area was higher than that in non-reservoir area in three gorges area, but the severe case rate in the reservoir area was lower than that in the non-reservoir area. The cases were mainly children aged ≤3 years in both reservoir and non-reservoir areas. There was difference in pathogen condtituent of HFMD between reservoir area and non-reservoir area. It is suggested that the prevention and control of HFMD should be focused on the pathogen changes, and EV71 vaccination and comprehensive measures should be taken to protect the population at high risk to reduce the overall incidence of HFMD in three gorges area.