Background Gastrointestinal infections in Germany account for 24.5 million outpatient visits annually. Surveillance of gastrointestinal infections in emergency departments strengthens timely outbreak detection and disease trend monitoring.

Aim We developed a syndrome definition for automated syndromic surveillance of gastrointestinal infections in emergency departments, and validated it against statutory laboratory-based surveillance.

Methods To develop a syndrome definition, we selected presenting complaints (Canadian Emergency Department Information System) and diagnoses (ICD-10). We validated the definition through time series and cross-correlation analysis, comparing trends between syndromic and laboratory-based surveillance. We analysed German emergency department registry (AKTIN) data and included emergency departments that continuously transferred (01/2019-06/2023) data. As reference we combined statutory norovirus-gastroenteritis, rotavirus-gastroenteritis, campylobacteriosis and salmonellosis notifications.

Results Our syndrome definition combined presenting complaints (diarrhoea, vomiting and nausea) and diagnoses (Intestinal infectious diseases). Accordingly, in 7 emergency departments with n = 864,353 visits, 2.1% (n = 18,158) were gastrointestinal infection cases. Of those, 57% (n = 10,424) were female, with 23% 0–19 years (n = 4,108) and 23% 20–29 years (n = 4,116) old. We visually observed similar gastrointestinal infection trends in both surveillance systems. The cross-correlation was 0.73 (95%-confidence interval 0.61–0.85; p<0.001) at lag −1, indicating a 1-week relative reporting delay of laboratory-based surveillance.

Conclusion The coherent trends and significant cross-correlation validated our syndrome definition, which adequately captures gastrointestinal infection cases in emergency departments. Our novel automated surveillance complements laboratory-based surveillance, while offering advantages regarding timeliness and reduced workload. Therefore, it will be implemented in national routine surveillance.

The authors have declared no competing interest.

The Robert Koch Institute is an Institute within the portfolio of the German Federal Ministry of Health. The AKTIN emergency department registry is funded by the German Federal Ministry of Education and Research. This publication was partially funded by the German Federal Ministry of Education and Research (BMBF) Network of University Medicine 2.0: "NUM 2.0", Grant No. 01KX2121, Project: AKTIN-EZV, AKTIN@NUM

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

Ethics Committee of the medical facility of the Otto von Guericke University in Magdeburg gave ethical approval for The AKTIN emergency department registry (ethics approval: 160/15 and 52/21). Primary data is stored (pseudonymized and decentralized) in local data warehouses at each hospital. AKTIN provides anonymized data to researchers after approval from their Data Use and Access Committee. Therefore, an additional ethics approval for this specific study is not required. Moreover, the data protection officer at the Robert Koch Institute gave approval for the use of routine emergency department data for surveillance (BDS/ISB, 09-01-2019).

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↵18 AKTIN Research Group: Markus Baacke; Jaqueline Bauer; Michael Bernhard; Jonas Bienzeisler; Sabine Blaschke; Jörg Brokmann; Volker Burst; Hans-Jörg Busch; Harald Dormann ; Christoph Duesberg; Saskia Ehrentreich; André Gries; Thomas Händl; Eric Handmann; Felix Hans; Frank Hanses; Thomas Henke; Matthias Klein; Tobias Hofmann; Marina Karg; Jan Kleinekorth; Alexander Kombeiz; Bernhard Kumle; Philipp Kümpers; Christoph Lewejohann ; Alexander Dinse-Lambracht; Benjamin Lucas; Carsten Mach; Raphael W. Majeed; Jürgen Neubauer; Ronny Otto; Thomas Peschel; Norbert Pfeufer; Rainer Röhrig; Wiebke Schirrmeister; Domagoj Schunk; Wolfgang Stahl; Hartmut Stefani; Lucas Triefenbach; Bernd UIrich; Felix Walcher; Markus Wehler; Hardy Wenderoth ; Sebastian Wolfrum; Christian Wrede; Markus Zimmermann