Molecular Epidemiology of Human Enterovirus 71 at The Origin of An Epidemic of Fatal Hand, Foot and Mouth Disease Cases in Cambodia

Dr. Veasna Duong
Deputy Head,
Virology Unit Team,
Institut Pasteur du Combodge,
Cambodia

ABSTRACT

Human enterovirus 71 (EV-A71) causes Hand, Foot, and Mouth Disease (HFMD). EV-A71 circulates in many countries, causing large epidemics especially in the Asia-Pacific region since 1997. In April 2012, an undiagnosed fatal disease with neurological involvement and respiratory distress occurred in young children admitted to the Kantha Bopha Children’s Hospital in Phnom Penh, Cambodia. Most died within a day of hospital admission, causing public panic and international concern. In this present study, we describe the Enterovirus (EV) genotypes isolated during the outbreak in 2012 and the following year. From June 2012 to November 2013, 312 specimens were collected from hospitalized and ambulatory patients and tested by generic EV and specific EV-A71 RT-PCR. EV-A71 was detected in 208 clinical specimens while other EVs were found in 32 patients. VP1 and/or complete genome were generated. Our phylogenetic analysis demonstrates that 80 EV-A71 strains sequenced belonged to subgenotypes C4a and 3 to genotype B5, and that some lineages of EV-A71 were appeared in Cambodia following separate introductions from neighbouring countries. Nineteen EV A (CV-A6 and CV-A16), 9 EV B (EV-B83, CV-B3, CV-B2, CV-A9, E-31, E-2 and EV-B80) and 4 EV C (EV-C116, EV-C96, CV-A20 and Vaccine related PV-3) strains were also detected. We found no molecular markers of disease severity. We report here that EV-A71 genotype C4 was the main etiological agent of a large outbreak of HFMD and particularly of severe forms associated by central nervous system infections. The role played by other EVs in the epidemic could not be clearly established.

The content is authorized by Dr. Veasna Duong on October 29, 2017.

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