A new report from the US Centers for Disease Control and Prevention (CDC) suggests that disease outbreaks tied to water often happen after people use spa pools or spas.

Published in the CDC's Morbidity and Mortality Weekly Report, the paper reveals that between 2009 and 2010, there were 81 outbreaks – defined as two or more people who visited the same location, at around the same time, becoming sick – and 1,326 cases of illness in the United States linked to recreational water exposure (pools, lakes, spa pools, etc), according to information reported from 28 US states and Puerto Rico.

According to the report, eighteen of these outbreaks (22 per cent) were linked with spa pools or spas and roughly 40 per cent occurred in February or March, with many of these stemming from hotels.

One of the most common illnesses linked with spa pool/spa outbreaks is an infection with the bacterium Pseudomonas aeruginosa. Healthy people can develop Pseudomonas aeruginosa infections, including ear infections or skin rashes, after exposure to spa pools that have not been properly chlorinated, according to the CDC.

Most recreational-water outbreaks occurred in the summer months: Of the 57 outbreaks in treated facilities (such as pools), 25 took place in July or August.

An additional 24 outbreaks came from untreated natural water, almost all of which occurred in spring or summer.