A study from Japan has confirmed the potential of PCR and phylogenetic analysis to enable identification of group A coxsackieviruses and diagnosis of illnesses they cause in children. Throat swabs cultured from 246 children with acute summertime febrile illness yielded 33 enteroviruses—coxsackievirus A16 from a case of herpangina, 32 enteroviruses from children with pharyngitis/tonsillitis—but none from children with febrile seizures.

Nested PCR (PCR-FMU) of culture negative samples showed enteroviral DNA in 17/22 cases of herpangina, 11/21 febrile seizures, and 26/135 pharyngitis/tonsillitis. Further testing of the positive samples with other sequences and phylogenetic analysis showed that those positive for group A coxsackieviruses featured in 14/17 cases of herpangina, 8/11 febrile seizures, and 16/26 pharyngitis/tonsillitis. Two clusters within group A corresponded to year of isolation.

The children came from Fukushima Prefecture with summer fevers in June-August 1997 and 1998. Twenty four had herpangina, 21 febrile seizures, and 210 pharyngitis/tonsillitis. Throat swabs were taken into transport medium, which was divided. One sample was used for virus culture and identification, the other subjected to PCR-FMU to detect enteroviral DNA. Positive samples were typed by PCR-MBCL and phylogenetic analysis according to similarity of sequences in the VP4 region compared with VP4 region of all 64 human enteroviruses in the MBCL database.

Group A coxsackieviruses are difficult to culture. By using PCR and phylogenetic analysis the researchers had found that enteroviruses were associated with summertime febrile seizures in children and wanted to see whether group A coxsackieviruses were associated with other summertime febrile illnesses.

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