Isolation of echovirus 9 from meningitis cases and exanthema cases, June 2000 - Miyazaki
(IASR 2000; 21: 168-169)

In Miyazaki Prefecture isolation of echovirus 9 (E9) has been increasing, and 57 isolates are obtained as of June 2000. Most of those isolates are collected from children with exanthema aged between 0-13 years (mean 2 years, no difference between boys and girls). Of those 57 isolates, 15 were collected in outbreaks that occurred at nursery schools and kindergartens, and 9 isolates were obtained within families and siblings. Clinical symptoms included fever (average 38.5C), exanthema (papule, erythema), upper respiratory infection (pharyngeal injection, pharyngitis), which resemble those of rubella or streptococcal infection. Only one isolate was collected from a case with aseptic meningitis.

All isolates except one from the meningitis case were collected from pharyngeal swabs or nasal discharge (average at the 3rd ill day, the latest 7th day). CaCo-2, Vero, and HeLa cell lines were employed, and CaCo-2 cell was the most susceptible; cytopathic effect was observed 2-3 days after inoculation and all 57 isolates were detected by the second inoculation.

During January to June 2000, 83 enteroviruses were isolated in Miyazaki Prefecture. Since E9 had been isolated since January when the epidemic had seldom been observed, and E9 has been frequently isolated every 3 years (i.e. 1994, 1997), this summer has been expected to have its epidemics. E9 tended to develop exanthema in infants, and aseptic meningitis in schoolchildren.

In total 22 echovirus 25 (E25) were isolated by the end of June. It is often difficult to clinically distinguish E25 from E9 infection. Of E25 case children (0-2 years), 9 cases (41%) were less than 12 months old. E25 is more isolated from younger children.

Reported by: Syuji Yoshino, Kazuhiro Kizoe, Seigo Yamamoto, Utako Iwaki, Miyazaki Prefectural Institute for Public Health and Environment

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