Cryptosporidiosis Outbreak Chester County Pennsylvania 2007

In summer, 2007 the Chester County Health Department experienced the largest communicable disease outbreak in its 40 year history. The outbreak - Cryptosporidosis associated with public swimming pools - occurred as a result of a power failure followed by improper chrlorine monitoring at a large university pool. This pool provided swimming lessons to 1000-1100 youth per day. The outbreak spanned four months. Almost 800 people were reported confirmed and/or probable for Cryptosporidosis.

The outbreak spread to other public pools across the County and in neighboring counties. Staff closed thirty Chester County pools during the season; some were closed more than once. Staff collaborated with a number of State agencies and local health departments to establish statewide pool operator guidelines which, heretofore, did not exist. Similarly, staff worked closely with neighboring county health departments to establish a uniform response to controlling the outbreak and preventing future cases. The Centers for Disease Control was also consulted during the investigation.

Prior to the start of the 2008 swimming pool season, staff held an educational forum for public swimming pool operators to review the State guidelines and proper maintenance of public pools. The Department also increased its inspection of public swimming pools across the county and revised its swimming pool regulations. There were no Cryptosporidosis outbreaks associated with public swimming pools reported in Chester County, PA in 2008.