Objective: To investigate the etiology of hand, foot and mouth disease (HFMD) in Beijing during 2013, and study the clinical characteristics of HFMD caused by the main serotypes of enterovirus in the study.

Method: Clinical data and 128 stool samples were collected from 128 hospitalized children with HFMD in Beijing Ditan Hospital during 2013. One step RT-PCR method was used for enterovirus genotyping to investigate the etiology of HFMD. Clinical characteristics of HFMD caused by the main serotypes of enterovirus were analyzed. And VP1 segments of the main virus were amplified to construct phylogenetic tree for the phylogenetic analysis.

Result: A total of 128 hospitalized children with HFMD were included. HFMD was more likely developed in children under 2 years of age (81.6%, 102/125); 11 different enteroviruses were genotyped, with a total enterovirus positive rate of 76.6% (98/128); the positive rate of coxsackievirus A6 (CA6), 43.0% ( 55/128), was the highest, followed by enterovirus 71 (EV71), accounting for 14.8% (19/128). HFMD caused by CA6 was atypical, the rashes of which involved the perioral, trunk, limbs, face and neck (47%, 26/55), besides the common parts. Of the 55 cases caused by CA6, 6 children had clinical manifestations of nervous system involvement, one of whom even displayed type 2 respiratory failure. Mental status change more likely to occur in EV71-infected children than in CA6-infected ones (42% (8/19) vs. 11% (6/55) (χ(2)=7.041, P=0.008)); 13 children displayed onychomadesis, including 12 CA6 cases (23%, 12/53) and 1 CA10 cases (17%, 1/6), in the convalescence of hand, foot and mouth disease, and the correlation between onychomadesis and CA6 infection was significant (χ(2)=9.297, P=0.002). Phylogenetic analysis of 33 CA6 VP1 showed that the CA6 isolates of this study were highly similar to that of Taiwan and the nucleotide similarity was 95.91%-98.89%.

Conclusion: CA6 was the major pathogen of hospitalized children with hand, foot and mouth disease in Beijing during 2013, followed by EV71. The rashes caused by CA6 involved a wide range of skin sites and patients with CA6 infection displayed manifestations of neurological involvement or pulmonary edema similar to EV71 infection. Mental status change more likely occurred in EV71-infected children when neurological system was involved..