Molecular epidemiology of enterovirus from children with herpangina or hand, foot, and mouth disease in Hangzhou, 2016

Enteroviruses (EVs) are the major cause of hand, foot, and mouth disease (HFMD) and herpangina in children. In this study, we conducted a molecular investigation of EVs in throat swab samples from children in Hangzhou, China with a diagnosis of HFMD or herpangina. EVs were detected using one-step real-time RT-PCR, and their serotypes were determined based on partial VP1 gene sequences. The molecular typing results revealed the presence of six different EV serotypes in HFMD cases, including coxsackievirus (CV) A16 (20/30, 66.7%), CVA4 (3/30, 10.0%), CVA6 (3/30, 10.0%), EVA71 (2/30, 6.7%), CVB4 (1/30, 3.3%), and CVB5 (1/30, 3.3%). Eleven different EV serotypes were detected in herpangina cases, among which CVA4 was the most frequently detected serotype (105/170, 61.8%), followed by CVA16 (30/170, 17.6%), CVB4 (9/170, 5.3%), CVA6 (6/170, 3.5%), CVB3 (5/170, 2.9%), CVA10 (3/170, 1.8%), EVA71 (4/170, 2.4%), Echo9 (3/170, 1.8%), CVA9 (2/170, 1.2%), CVB1 (3/170, 1.8%) and CVA5 (1/170, 0.6%). The nucleotide sequence identity of EV strains from the same subtype ranged from 80.7% to 100%, and most of the EVs were closely related to virus strains found in Australia and mainland China. In conclusion, CVA 16 and CVA 4 were the main serotypes causing HFMD and herpangina, respectively, in children in Hangzhou in 2016. Most of these EVs were closely related to virus strains from Australia and mainland China.