An outbreak of coxsackievirus A6 hand, foot, and mouth disease associated with onychomadesis in Taiwan, 2010

Abstract

Background: In 2010, an outbreak of coxsackievirus A6 (CA6) hand, foot and mouth disease (HFMD) occurred in Taiwan and some patients presented with onychomadesis and desquamation following HFMD. Therefore, we performed an epidemiological and molecular investigation to elucidate the characteristics of this outbreak.

Methods: Patients who had HFMD with positive enterovirus isolation results were enrolled. We performed a telephone interview with enrolled patients or their caregivers to collect information concerning symptoms, treatments, the presence of desquamation, and the presence of nail abnormalities. The serotypes of the enterovirus isolates were determined using indirect immunofluorescence assays. The VP1 gene was sequenced and the phylogenetic tree for the current CA6 strains in 2010, 52 previous CA6 strains isolated in Taiwan from 1998 through 2009, along with 8 reference sequences from other countries was constructed using the neighbor-joining command in MEGA software.

Results: Of the 130 patients with laboratory-confirmed CA6 infection, some patients with CA6 infection also had eruptions around the perioral area (28, 22%), the trunk and/or the neck (39, 30%) and generalized skin eruptions (6, 5%) in addition to the typical presentation of skin eruptions on the hands, feet, and mouths. Sixty-six (51%) CA6 patients experienced desquamation of palms and soles after the infection episode and 48 (37%) CA6 patients developed onychomadesis, which only occurred in 7 (5%) of 145 cases with non-CA6 enterovirus infection (p < 0.001). The sequences of viral protein 1 of CA6 in 2010 differ from those found in Taiwan before 2010, but are similar to those found in patients in Finland in 2008.

Conclusions: HFMD patients with CA6 infection experienced symptoms targeting a broader spectrum of skin sites and more profound tissue destruction, i.e., desquamation and nail abnormalities.

Figure 1

A 2-year-5-month-old boy experienced prominent skin eruptions and vesicles on his buttocks (a). A 2-year-6-month-old boy had fingernail abnormalities 3 weeks after hand, foot, and mouth disease (b). Another 4-year-old boy presented with desquamation on his feet 1 week after the CA6 infection episode (c); he developed nail shedding on his right index finger in the following weeks (d) and recovered gradually.

Figure 2

Phylogenetic analysis of Coxsackievirus A6 strains based on the partial VP1 gene sequence (nucleotide position 196-447) was performed using the isolates in 2010, 52 previous CA6 strains isolated in Taiwan from 1998 through 2009, along with 8 sequences obtained from Genbank (7 strains from Finland, and the prototype strain, Gdula). Clade I included the 52 strains isolated from 1998 through 2009 in Taiwan, while clade II included the 123 strains isolated in Taiwan in 2010 (the compressed subtree indicated by the bold triangle) and the 7 strains isolated in Finland in 2008.