The 131st Annual Meeting (November 15-19, 2003) of APHA

The 131st Annual Meeting (November 15-19, 2003) of APHA

4035.0: Tuesday, November 18, 2003 - 8:30 AM

Abstract #55183

An outbreak of Cyptosporidiosis in a public swimming pool

Lionel S Lim, MBBS1, Prathibha Varkey, MD, MPH1, Peter Giesen, MS2, and Larry Edmonson, MPH3. (1) Division of Preventive Medicine, Mayo Clinic, 200 First Street SW, Baldwin 5A, Rochester, MN 55905, (507) 284-3195,, (2) Division of Environmental Health, Olmsted County Public Health Services, 2100 Campus Drive SE, Rochester, MN 55904, (3) Division of Disease Prevention and Control, Olmsted County Public Health Services, 2100 Campus Drive SE, Rochester, MN 55904

Background: In May 1998, the Olmsted County Public Health Department initiated an investigation when several members of a local competitive swimmers’ group developed a diarrheal illness following a banquet. A foodborne outbreak was ruled out after an initial case-control investigation of 40 competitive swimmers. Interviews were conducted; stool samples and swimming pool water and filter material analyzed to determine the source of the outbreak. A case was defined as a person who experienced diarrhea for 3 or more days.

Results: Twenty-six of the 206 interviewed met the case definition. The most common symptoms were diarrhea (100%), abdominal cramps (81%), and nausea (77%). The median duration of symptoms was 9 days. The index case was a preschool swimmer. The attack rates were higher in the competitive swimmers (61%) compared to the non-competitive swimmers (9%) (p < 0.0001). Stool testing confirmed Cryptosporidium in 3 preschool swimmers and 1 competitive swimmer.

Discussion: The outbreak of Cryptosporidiosis was associated with exposure to a contaminated swimming pool. Based on the even distribution of case onset among preschoolers, it is likely that the preschool swimmers aided in the propagation of this outbreak. The high attack rate experienced by the competitive swimmers is likely from prolonged exposure to the pool water relative to the other swimmers. A high index of suspicion as well as rapid assessment and control are necessary during outbreaks of Cryptosporidiosis. Public awareness including avoidance of recreational water facilities during diarrheal illness, and proper hygiene are vital in preventing Cryptosporidiosis.

Learning Objectives:

Keywords: Environmental Health, Infectious Diseases

Presenting author's disclosure statement:
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.

Handout (.ppt format, 883.0 kb)

Results From Outbreak Investigations: Implications for Public Health Practice

The 131st Annual Meeting (November 15-19, 2003) of APHA