Cryptosporidiosis Outbreak at a Summer Camp — North Carolina, 2009

In July 2009, local, regional, state, and federal public health officials investigated a cryptosporidiosis outbreak at a youth summer camp in North Carolina. The investigation identified 46 laboratory-confirmed and probable cryptosporidiosis cases at the camp. Analyses of data from a retrospective cohort study of staff members revealed that eating ham from a sandwich bar that included camp-grown raw produce and sharing a cabin with an ill person were significantly associated with illness. Cryptosporidium isolates from stool specimens of livestock and humans at the camp were of the identical Cryptosporidium parvum subtype, IIaA17G2R1, indicating that zoonotic transmission had occurred, and suggesting a link not implicated by traditional epidemiologic methods. This investigation underscores the importance of reducing the risk for Cryptosporidium transmission in camp settings and the value of Cryptosporidium subtyping as a tool to elucidate cryptosporidiosis epidemiology.