Article in Japanese

Echovirus 11 meningitis in childhood: A retrospective observational study at two institutions in Kobe, Japan 2023-2024

Moeka Kubo^1）, Keigo Hamahata^2）, Ai Mori^3）, Ryohei Nomoto^3）, Kenichi Isome^1）, Yu Kawasaki^1）, Aya Iwata^1）, Kousaku Matsubara^1）

In 2022-2023, an epidemic caused by a new variant, designated as new lineage 1, of echovirus 11 （E11） emerged in several European countries, and several deaths of affected neonates were reported. However, the current epidemiology of childhood E11 infection in Japan and the genomic information of the causative E11 remain to be fully elucidated. The aim of this study was to describe the clinical features of children with E11 meningitis, who were hospitalized at two institutions in Kobe, Japan, in 2023-2024, and to analyze the nucleotide sequence of the viruses detected. A total of six patients （four boys） were identified: one in September 2023 and five in August-November 2024. The age of onset ranged from seven days to nine years, and five patients were less than two months old. All patients became afebrile within four days, showed no elevation of liver enzymes, and were discharged from the hospital without sequelae. Phylogenetic analysis of the VP1 and VP4/2 regions of E11 revealed that four of the five strains （80%） in 2024 belonged to new lineage 1 and the other two were classified as non-new lineage 1, exhibiting high genetic homology within each group. The study showed that the clinical course of E11 meningitis cases during the study period was favorable, and that while there were two groups of E11 meningitis-causing pathogens, the new lineage 1 strain from European countries contributed to the 2024 epidemic in Kobe.

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1）Department of Pediatrics, Kobe City Nishi-Kobe Medical Center
2）Department of Pediatrics, Kobe City Medical Center General Hospital
3）Health Research Department 2, Kobe Institute of Health

Key words	aseptic meningitis, echovirus 11, multiplex polymerase chain reaction-based testing, neonate, new lineage 1
Received	March 2, 2024
Accepted	April 15, 2025

37 (2)：165─176,2025