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©The Author(s) 2025. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Virol. Dec 25, 2025; 14(4): 110435
Published online Dec 25, 2025. doi: 10.5501/wjv.v14.i4.110435
Published online Dec 25, 2025. doi: 10.5501/wjv.v14.i4.110435
Comparison of three pediatric studies investigating acute hepatitis of unknown etiology
Haruki Komatsu, Department of Pediatrics, Komatsu Children’s Clinic, Yachiyo 276-0040, Chiba, Japan
Author contributions: Komatsu H wrote this article and prepared all the figures and tables.
Conflict-of-interest statement: Komatsu H has no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.
Open Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Haruki Komatsu, MD, PhD, Department of Pediatrics, Komatsu Children’s Clinic, 4-2-1 Midorigaoka-nishi, Yachiyo 276-0040, Chiba, Japan.
Received: June 6, 2025
Revised: August 12, 2025
Accepted: September 19, 2025
Published online: December 25, 2025
Processing time: 202 Days and 10.7 Hours
Revised: August 12, 2025
Accepted: September 19, 2025
Published online: December 25, 2025
Processing time: 202 Days and 10.7 Hours
Core Tip
Core Tip: The rate of positivity for adeno-associated virus serotype 2 (AAV-2) was 80% or greater in cases of acute hepatitis of unknown etiology (AHUE) according to metagenomic sequencing and real-time polymerase chain reaction. AAV-2 RNA was detected in the nuclei and cytoplasm of ballooned hepatocytes through in situ hybridization. No distinct clade was observed in the phylogenetic tree analysis of whole genomes of AAV-2 isolated from cases. Coinfection of AAV-2 with one or more helper viruses (HAdV, HHV-6B, EBV, etc.), a high viral load of AAV-2 in blood, anti-AAV-2 IgM and human leu