# Detection of enteric pathogens in young children before and during acute gastroenteritis: results from a prospective German birth cohort study (LoewenKIDS)

## TL;DR

This study found that enteric viruses, especially norovirus and adenovirus, are strongly linked to acute gastroenteritis in young children, while bacteria and parasites are less significant.

## Contribution

The study provides new insights into the etiological role of specific enteric pathogens in acute gastroenteritis among young children in high-income countries.

## Key findings

- Enteric viruses were detected in 64% of symptomatic samples and were strongly associated with gastrointestinal symptoms.
- Bacteria and parasites showed no significant association with symptoms, with bacteria detected equally in symptomatic and asymptomatic samples.
- Norovirus GII, astrovirus, and sapovirus showed increased pathogen loads in symptomatic samples compared to asymptomatic ones.

## Abstract

To identify enteric pathogens in pediatric acute gastroenteritis (AGE) and assess their etiological relevance by comparison with samples during asymptomatic period.

Children < 2 years of age (n = 89) were prospectively enrolled as part of the population-based birth cohort LoewenKIDS. Asymptomatic stool samples were collected regularly, and symptomatic samples were collected after the occurrence of > 3 loose stools and/or one vomiting in 24 h. Intraindividual pairs of symptomatic and preceding asymptomatic samples for each child were analyzed for 25 enteric pathogens via multiplex real-time RT-PCR.

Enteric viruses were detected in 64% (57/89) of symptomatic samples and significantly associated with gastrointestinal symptoms (Odds Ratio [OR] 3.9; 95% Confidence Interval [CI] 2.1–7.3). The most common viruses in AGE were norovirus (Genogroups GI and GII) (36%, 32/89) and adenovirus (27%, 24/89). Bacteria were detected in 46% (41/89) of symptomatic samples and 43% (38/89) of asymptomatic ones, with no association to symptoms (OR 1.1; 95% CI 0.6-2). The most common bacteria in AGE were Enteropathogenic Escherichia coli (28%, 25/89) and Clostridium difficile (16%, 14/89). Dientamoeba fragilis was the only detected parasite in AGE (7%, 6/89), and was not associated with symptoms (OR 1.4; 95% CI 0.4–5.5). Pathogen loads in symptomatic and asymptomatic pairs correlated with symptoms for norovirus GII, astrovirus and sapovirus (each p < 0.01), but not for other pathogens.

This study supports the clinical significance of detection of viral pathogens in young children with acute gastroenteritis and without relevant comorbidities in high-income countries, but limits the significance of enteric bacterial and parasitic pathogens detection, partly due to constraints in their specific identification.

Clinicaltrials.Gov Identifier: NCT02654210.

The online version contains supplementary material available at 10.1007/s15010-025-02670-1.