In late 2012, Minnesota Department of Health (MDH) officials in investigated an outbreak of Cryptosporidiosis. The first two cases were identified through routine surveillance. Interviews with parents of the cases revealed that both had attended a birthday party held on a farm on November 9. The two cases reported onset of illness on November 14 and November 15. Both cases were female and 9 years old.

An MDH epidemiologist contacted the party host who agreed to answer some questions. A total of 10 children attended the party including 4 of the birthday girl's siblings. Two adults also attended. This was a sleepover birthday party. While at the party, the children petted goats, horses, mini llamas, chickens, and ducks. They also bottle fed two calves that had been purchased two weeks prior to the party. One of the calves had diarrhea at the time of the party. MDH offered to test the animals on the farm, but the party host declined.

On additional case was identified by speaking with the party host; this third case was the birthday girl. She became ill 5 days after her party and reported diarrhea, cramps, fever, and weight loss. A stool specimen tested negative for Cryptosporidium. The party host denied any other illness among party attendees.