In children with acute gastroenteritis (AGE), vomiting often precedes diarrhea. To establish the diagnosis of AGE, enteropathogen detection typically relies on diarrheal stool samples. However, testing requires sufficient stool sample, which may not be easily available. Recent studies suggest that in children presenting to emergency departments with presumed AGE with isolated vomiting, an enteropathogen can be identified using rectal swabs and molecular diagnostic tests. The rate of enteropathogen detection in children with isolated vomiting due to AGE may differ in various populations. Using rectal swabs and molecular diagnostic tests, we plan to assess the proportion of children with isolated vomiting with presumed AGE in whom an enteropathogen can be identified.

This will be a prospective cohort study. Children younger than 5 years with presence of ≥3 episodes of vomiting due to presumed AGE, lasting no longer than 7 days before enrolment, will be recruited. A total of 198 participants will be recruited and a rectal swab will be collected. The participants will be contacted 14 days after enrollment to complete a survey regarding symptoms experienced during that period and to identify any additional clinical care.

Inclusion Criteria:

• age 0-5-year-old
• presence of ≥3 episodes of vomiting due to presumed AGE at inclusion
• <7 days of symptoms at the time of inclusion
• signed written informed consent

Exclusion Criteria:

• anticipated inability to complete 14 days follow-up
• history of neutropenia (as rectal swabs are contraindicated)
• critically ill status requiring urgent medical intervention
• inability to provide a rectal swab for testing
• chronic gastrointestinal tract disorders such as inflammatory bowel disease, cystic fibrosis, coeliac disease
• immunodeficiency

Children younger than 5 years with presence of ≥3 episodes of vomiting due to presumed AGE, lasting no longer than 7 days before enrolment, will be recruited.