Assessment of swimmer behaviors on pool water ingestion.

Enteric pathogens in pool water can be unintentionally ingested during swimming, increasing the likelihood of acute gastrointestinal illness (AGI). AGI cases in outbreaks are more likely to submerge heads than non-cases, but an association is unknown since outbreak data are self-reported and prone to bias. In the present study, head submersion frequency and duration were observed and analyzed for associations with pool water ingestion measured using ultra high pressure liquid chromatography - tandem mass spectrometry. Frequency of splashes to the face was also quantified. Reliable tools that assess activities associated with pool water ingestion are needed to identify ingestion risk factors and at-risk populations. Objectives were to determine if the observed activities were associated with ingestion, and to test environmental sensor and videography assessment tools. Greater frequency and duration of head submersion were not associated with ingestion, but frequency of splashes to the face, leisurely swimming, and being ≤18 were. Videography was validated for assessing swimmer head submersion frequency. Results demonstrate ingestion risk factors can be identified using videography and urine analysis techniques. Expanding surveys to include questions on leisure swimming participation and frequency of splashes to the face is recommended to improve exposure assessment during outbreak investigations.