The association between consuming bivalves, and acute gastroenteritis and norovirus in Tokyo, Japan

Abstract

A prospective matched case‐control study was conducted to evaluate associations between dietary histories, including consumption of bivalves, diarrhea, and norovirus positive diarrhea in adult ambulatory patients at an outpatient clinic of a hospital in Tokyo, Japan. Ambulatory cases with diarrhea were matched with nondiarrheal control patients, who visited the same clinic. A standardized questionnaire was used to obtain patients’ information, including histories of food consumption and clinical information. Norovirus infection was confirmed using real‐time reverse transcription polymerase chain reaction. A total of 207 patients, including 69 diarrheal cases and 138 nondiarrheal cases were included in the analysis. Among them, 60 (29.0%) participants reported consuming bivalves. Norovirus was detected in 35% (24/69) of diarrheal cases. Of those, 10 (41.7%) reported consumption of bivalves and of those, 6 (60.0%) consumed raw bivalves. The proportion of those who consumed raw bivalves was significantly higher in norovirus‐positive diarrheal cases than in norovirus‐negative diarrheal cases (25.0% vs 6.7%; odds ratio [OR], 4.67; 95% confidence interval [CI], 1.1‐20.7) and matched nondiarrheal controls (25.0% vs 6.3%, OR: 5.00; 95% CI, 1.1‐22.2). The attributable fraction of consuming raw bivalves for norovirus‐associated diarrhea to matched nondiarrheal controls was 20.0%. Consuming raw bivalves was substantially attributed to norovirus‐associated diarrhea in adult ambulatory patients and preventive measures for reducing the risk associated with consumption of raw bivalves could decrease the incidence of norovirus‐associated diarrhea.

Occurrence and distribution of fecal indicators and pathogenic bacteria in seawater and Perna perna mussel in the Gulf of Annaba (Southern Mediterranean)

“…They may therefore jeopardize human health, especially when they are consumed as seafood (Stabili et al 2005;Zannella et al 2017, Vincy et al 2017. Numerous studies have reported that many serious illnesses such as acute gastroenteritis and hepatitis E virus infections are related to the presence of pathogenic microorganisms in bivalves mollusks, especially when they are eaten raw or undercooked (Le Guyader et al 2006;O'Hara et al 2018;Kobayashi et al 2019;Fouillet et al 2020). Hence, there is an urgent need for an overall assessment to predict the presence of these infectious agents related to waterborne outbreaks, and to prevent the impacts of fecal contamination on human and environmental health.…”