Clinico Virological Characterization of Hand, Foot and Mouth Disease in a Tertiary Care Hospital, South India.

Introduction: Hand, foot, and mouth disease (HFMD) is a common childhood infectious disease, caused by enteroviruses (EVs) which can present with typical or atypical lesions. Although the disease is self-limiting, it can also lead to serious complications. In the era of polio eradication, it is important to understand the population dynamics of enteroviruses causing HFMD as one of the circulating strains may become dominant.

Methods: It was a collaborative study carried out in the Department of Dermatology and Microbiology of a tertiary care teaching hospital. The throat swabs were collected from 132 suspected HFMD cases. Real-time polymerase chain reaction (PCR) was performed to detect the presence of pan enteroviruses, followed by genotype-specific PCR targeting Human Enterovirus 71 (HEV-71) and Coxsackie virus A16 (CVA-16) and CVA-6 for pan Enterovirus-positive samples. Follow-up samples were collected from 14 children in the 2^nd week and subjected to molecular testing to detect enteroviruses.

Results: Among 132 children suspected to have HFMD, 44 were girls and 88 were boys, and the majority of them 76.5% (101/132) were under 2 years of age. A history of exposure to a similar clinical presentation was present in 15 children. Of 132 suspected cases, 60 samples (45.5%) were positive for pan Enterovirus. The predominantly circulating genotype was found to be CVA-6 (31.6% [19/60]). There were about 10 cases (16.6%) which had co-infection with both HEV71 and CVA-6. Rash with fever was the most common presentation (57%). In most of the cases with HEV 71, 92.3% (12/13) presented within 3 days of illness to the health-care facility. Of 60 positive cases, 25% (15/60) of children had the atypical distribution of rashes in the face, trunk, genitalia, thigh, neck, and axilla and 16.7% of children (10/60) had the atypical type of lesion either only papular lesions or erythema multiforme. Out of 14 follow-up samples, 13 were negative for EVs; one was positive for pan EV in the 2^nd week, however, the patient lost to follow-up after that.

Conclusion: HFMD outbreaks in our region were caused by various genotypes of enteroviruses. No severe complications were seen in the affected children. Nearly 30% had atypical presentation either in the form of lesion or site. Robust molecular epidemiological surveillance of HFMD is required to know the strain variations and other emerging genotypes in our setup.