Family outbreak of an infection with a recombinant Coxsackie A virus in eastern Switzerland

We report on an unusual familial outbreak of a coxsackie virus infection in Switzerland in which five family members were affected. Most of the patients presented with signs of meningitis, and four were hospitalized.

In three individuals, the virus was detected in the cerebrospinal fluid, pharynx, and stool, respectively. The genome was sequenced in specimens of two patients.

The nucleotide sequences of both virus strains were identical. Blast search revealed that the first half of the sequence was 88 % homologous to Enterovirus 75 (EV-75), 87 % with Echovirus 11 (E-11), and 84 % homologous to Coxsackie virus A9 (CV-A9). The second half of the sequence was 77 % homologous to EV-75, 75 % to E-11, and 91 % to CV-A9.

We propose that the isolated virus strain is a recombinant strain with a 5' untranslated region and with the start of the VP4 sequence originating from E-11/EV-75 and the rest of the genome originating from CV-A9. Interestingly, this novel virus strain showed an exceptional virulence and rapid spread. Two weeks after the initial outbreak in this family, a similar outbreak was observed in a second geographic area roughly 100 km distant to the primary identification site, and another 2 months later this virus strain was found to circulate in the western part of Switzerland some 250 km distant to the primary locus. These findings suggest that genetic recombination has resulted in a novel enterovirus with features of high virulence, contagiosity, and spreading.