Circulation of multiple enterovirus serotypes causing hand, foot and mouth disease in India

Hand, foot and mouth disease (HFMD), a common contagious disease that usually affects children, can be caused by enteroviruses. Coxsackievirus A16 (CV-A16) and enterovirus 71(EV-71) are the major aetiological agents of HFMD. Other EV serotypes, CV-A4-7, CV-A9-10, CV-B1-3, CV-B5, E-4 and E-19, have also been found associated with both sporadic infections and outbreaks of HFMD. In India, outbreaks of HFMD have been documented; however, molecular characterization of the aetiological agents has rarely been reported. Cases of HFMD were identified during 2009-2010 on the basis of clinical features in southern and eastern parts of India. The aim of the present study was to detect and characterize the aetiological agents associated with the disease. A total of 89 specimens consisting of 41 sera, 24 vesicular fluids, 18 stools and 6 throat swabs were collected from 61 clinically diagnosed HFMD cases from southern and eastern parts of India. RT-PCR followed by sequencing of PCR amplicons and phylogenetic analysis were performed on all specimens for detection of EV RNA and identification of EV types. EV RNA was detected in 47.1% (42/89) of the specimens collected from 57.4% (35/61) of the HFMD cases. Thirty-six of 42 EV strains showed amplification of the VP1/2A junction or VP1 regions. Sequence analysis of the amplicons identified the presence of CV-A16 (54.8%), CV-A6 (38.1%), EV-71 (2.4%), CV-A10 (2.4%) and E-9 (2.4%) serotypes in the HFMD cases. The study documents CV-A16 and CV-A6 as major and CV-A10, EV-71 and E-9 as rare viral pathogens of HFMD in India.