Ambulatory Pediatric Surveillance of Hand, Foot and Mouth Disease as Signal of an Outbreak of Coxsackievirus A6 Infections, France, 2014-2015

Abstract

The clinical impact of enteroviruses associated with hand, foot and mouth disease (HFMD) is unknown outside Asia, and the prevalence of enterovirus A71 (EV-A71) in particular might be underestimated. To investigate the prevalence of enterovirus serotypes and the clinical presentations associated with HFMD in France, we conducted prospective ambulatory clinic-based surveillance of children during April 2014-March 2015. Throat or buccal swabs were collected from children with HFMD and tested for the enterovirus genome. Physical examinations were recorded on a standardized form. An enterovirus infection was detected in 523 (79.3%) of 659 children tested. Two epidemic waves occurred, dominated by coxsackievirus (CV) A6, which was detected in 53.9% of enterovirus-infected children. CV-A6 was more frequently related to atypical HFMD manifestations (eruptions extended to limbs and face). Early awareness and documentation of HFMD outbreaks can be achieved by syndromic surveillance of HFMD by ambulatory pediatricians and rapid enterovirus testing and genotyping.

Keywords: France; ambulatory; enterovirus A; foot and mouth disease; hand; human coxsackievirus infections; pediatric; sentinel surveillance; surveillance viruses.

Figure 1

Methodologic approach for enterovirus genotyping and distribution of types associated with hand, foot and mouth disease and herpangina, France, April 2014–March 2015. A) Semi-nested reverse transcription PCR (RT-PCR) A using primers specifically developed for enterovirus types belonging to the EV-A species was first performed for all clinical samples except 1. For this sample, the viral load was low, and the nested RT-PCR described by Nix et al. (27) was performed directly. If the semi-nested RT-PCR A was negative, the genotyping was alternatively performed by a semi-nested RT-PCR B with primers specific to the EV-B species (28) or a nested RT-PCR (27). B) Among other EV-A species, 5 different types were identified: coxsackievirus (CV) A4, n = 18; CV-A8, n = 16; CV-A2 and CV-A5, n = 5 each; and CV-A12, n = 1. Among EV-B species, 12 different types were identified: echovirus (E) 16 (E-16) and E-18 (n = 5 each); E-11 and coxsackievirus B3 (CV-B3; n = 4 each); CV-B1, CV-B2, CV-B4, CV-A9, and E-6 (n = 2 each); and E-3, E-5, and E-25 (n = 1 each). EV-A, Enterovirus A; EV-A71, enterovirus A71; EV-B, Enterovirus B; RT-PCR, reverse transcription PCR.

Figure 2

Participant flow diagram of enterovirus testing for the surveillance of hand, foot and mouth disease and herpangina, France, April 2014–March 2015. RT-PCR, reverse transcription PCR.

Figure 3

Weekly distribution of enterovirus infections associated with hand, foot and mouth disease and herpangina, France, April 2014–March 2015. Bar sections represent the number of enterovirus-positive (dark gray) and -negative (white) samples analyzed.

Figure 4

Phylogenetic tree based on partial viral protein (VP1) coding sequences of coxsackievirus (CV) A6, France, April 2014–March 2015. The maximum credibility tree is inferred with the partial VP1 sequence (369 nt, position 2,441–2,808 relative to the Gdula CV-A6 prototype strain). The phylogenetic relationships were inferred with a Bayesian method by using a relaxed molecular clock model. The tree was reconstructed using Figtree version 1.4.2 (http://tree.bio.ed.ac.uk/software/figtree). For clarity, the sequence names are not included in the tree. Circle sizes are proportional to posterior probability. Each tip branch represents a sampled virus sequence. The continents/countries where the virus strains were sampled are indicated by different colors: Europe, purple; France 2010, light blue; France 2014–2015, dark blue; the Americas, green; Asia, red. The inset shows the complete tree, with the box indicating the portion enlarged for clarity.