The Centers for Disease Control and Prevention (CDC) has released a report detailing a recreationalwaterborne- disease outbreak at a Maine hotel.

The outbreak occurred in March 2023 and affected 23 people who contracted Pseudomonas aeruginosa at an unidentified hotel swimming pool. People who swam in the pool on March 4 or 5 reported developing ear pain, rash, or pain or swelling in their feet and hands.

P. aeruginosa is a virulent pathogen that can cause acute otitis externa (‘swimmer’s ear’), folliculitis (hot tub-related rash), and painful nodules on the soles or palms.

According to the report, the hotel had been cited for multiple violations the previous year, including having no chemical feeder system.

Other violations included 1) no operator had successfully completed approved training, 2) no pool logs documenting free chlorine concentration readings at least three times per day while the pool was open for use, 3) no posted routine operating procedures. During a subsequent March 2023 inspection, although one operator had completed the required training, none of the other violations had been corrected.

Following the outbreak, hotel staff added an indeterminant amount of chlorine to the pool; therefore CDC inspectors did not bother collecting water quality and environmental samples.

The hotel pool remained closed while the violations were corrected.

Researchers noted that hotel pools are the source of a third of treated recreational water-associated outbreaks and the Pseudomonas outbreaks generally occur between January and April.

“Outbreak prevention strategies include maintaining chlorine concentration and otherwise vigilantly managing the pool, especially during January-April, and disseminating prevention messaging to pool and hot tub users,” they wrote.