Epidemiological Investigation of Sapovirus, Taiwan, September 2020–June 2024

Shu-Chun Chiu, Lun-Hao Hsieh, Ya-Chun Yu, Yu-Hua Chen, Yu-An Lu, Jen-Hung Chang, Jih-Hui Lin*

2025 Vol.41 No.18

Correspondence Author： Jih-Hui Lin

Abstract：

    The number of diarrhea outbreaks reported in Taiwan has increased over the years. In early 2024, multiple large foodborne outbreaks occurred across the country, causing public concern and leading to a sharp rise in reported cases and specimen submissions for testing, surpassing previous levels. Routine testing found no suspected pathogens in nearly 40% of the stool specimens associated with these outbreaks. We analyzed residual specimens from outbreak-associated diarrhea cases reported in Taiwan during September 2020 to June 2024 that had tested negative in routine examinations to conduct a molecular epidemiological analysis of pathogens.
    Among the 3,564 residual specimens tested, 256 (7.2%) were positive for sapovirus. Of these, 51.6% (132/256) were children aged five years or younger, making this age group the most affected. The most common outbreak settings were schools and congregate settings, accounting for 78.1% (200/256) and 11.3% (29/256) of cases, respectively. Furthermore, the investigation revealed that the predominant genotype shifted from GI to GII during the surveillance period, with sporadic detections of GIV and GV also observed. This evolving trend warrants ongoing monitoring.

Keywords：Diarrhea outbreaks, Sapovirus, Epidemiology