BACKGROUND: Zoonotic Cryptosporidium transmission is commonly associated with pre-weaned calf contact, but outbreaks associated only with goat contact have not been previously documented in the United States. In March 2016, the Indiana State Department of Health (ISDH) received a complaint regarding Cryptosporidium in goats purchased from an Indiana farm. In April and May, the ISDH identified two people with laboratory-confirmed Cryptosporidium from different households, both of which had purchased goats from the same farm.
METHODS: An environmental inspection was performed at the farm in April. Sales records from February 1 to May 5 were provided by the farmer. The ISDH administered a questionnaire and offered Cryptosporidium testing to members of households that purchased goats during this period. A confirmed case was defined as a patient with diarrhea, at least one additional symptom, and a positive laboratory test for Cryptosporidium; a probable case had diarrhea and at least one additional symptom; and a suspect case had diarrhea with no other symptoms.
RESULTS: Twenty-seven buyers were identified from the sales records in addition to the two index cases. The ISDH successfully contacted 14 (48%) households comprising 46 people. Among these, a total of 92 goats were purchased; the median number per household was three (range: 2–43) and the median age at purchase was three weeks (range: 1–168 weeks). Ten (71%) households reported illness among purchased goats; of these, five (50%) reported that goats were ill on the date of purchase. Twenty (43%) case patients were identified (three confirmed, 12 probable, and five suspect). All 20 (100%) case patients lived in a household that bought goats that were ill on or after the date of purchase. Illness onsets occurred within 2–12 days after purchase of the goats and occurred over an eight-week period from March to April. The attack rate was 43% among individuals and 36% among households. The farmer reported diarrhea in the herd, but did not have space available to isolate sick animals.
CONCLUSIONS: This is the first documented outbreak of zoonotic cryptosporidiosis associated only with goat contact in the United States. A strong association was observed between human illness and exposure to sick goats purchased from the farm. The incubation period and range of onset dates suggest zoonotic Cryptosporidium transmission in the case patients and ongoing transmission among the goats at the farm. Recommendations to the farmer included isolating sick animals, improving goat housing conditions, and not selling visibly sick goats.