Etiological surveillance results of hand, foot and mouth disease in Jiuquan, Gansu, 2010−2022

Objective To understand the etiological characteristics of hand, foot and mouth disease (HFMD) in Jiuquan, Gansu province, from 2010 to 2022 and provide evidences for the prevention and control of HFMD in the future.

Methods Throat swabs of HFMD cases were collected from 2010 to 2020 for the detection of enterovirus nucleic acid by real-time reverse transcription-polymerase chain reaction. The positive samples were detected for enterovirus 71 (EV71), coxsackie virus A16 (Cox A16), coxsackie virus A6 (Cox A6) and coxsackie virus A10 (Cox A10) with general primers of enterovirus.

Results A total of 1 639 samples of HFMD cases were tested from 2010 to 2022, and 1175 were positive for enterovirus nucleic acid, with a positive rate of 71.69%. There were significant differences in the annual composition of the pathogens (2010−2015: χ²=88.119, P<0.05, 2017−2021: χ²=210.864, P<0.05). In the past 13 years, Cox A16 was predominant, accounting for 35.23% of the total, followed by other enterovirus (28.94%). Cox A6 had gradually become predominant since 2016. The cases occurred all the year round, and two incidence peaks occurred each year, the first peak was during May-July, and the second peak (sub-peak) was during September-November. There were no significant differences in the positive rate of enterovirus detected with general primers in different age groups (χ²=12.207, P=0.142). However, there were significant differences in the composition of enterovirus types (χ²=59.532, P<0.05). The positive rate of EV71 was highest in 4-year-old group (21.96%) and lowest in 3-year-old group (11.04%). The positive rate of Cox A6 was highest in 9-year-old group (34.00%) and lowest in 8-year-old group (9.68%). The positive rate of Cox A10 was highest in 3-year-old group (1.95%). The positive rate of Cox A16 was highest in 6-year-old group (46.07%) and lowest in 2-year-old group (27.59%). The positive rate of other enterovirus was highest in 2-year-old group (41.38%) and lowest in 4-year-old group (22.75%).

Conclusion HFMD was caused by multi pathogens in Jiuquan, and the predominant pathogen varied with year. The typing and identification of other enterovirus should be strengthened. The HFMD surveillance, early warning, prevention, control and health education should be strengthened during May-July and September-November every year.