Minnesota health officials issued a health advisory Thursday for health providers to be aware of diarrheal illnesses that may be due to visiting farms. The Minnesota Department of Health is investigating an outbreak of diarrheal illness associated with visiting the Nelson Farm in Litchfield, MN (Meeker County).
Outbreaks associated with farm animal contact may include multiple pathogens including Salmonella, Campylobacter, Shiga toxin-producing E. coli (STEC), and Cryptosporidium.
Over 10 cases of diarrheal illness from 5 different schools have been reported, including three cases of laboratory-confirmed Cryptosporidium infection. All cases reported visiting the Nelson Farm as part of school sponsored trips starting on May 9. However, numerous school groups have visited the farm through May 25, so there could be many more individuals who are currently ill or incubating illness.
Symptoms and incubation periods vary between pathogens, but most patients present with diarrhea and abdominal pain that last longer than 3 days.
Patients with Salmonella infection generally present with diarrhea and fever that occur 12 to 72 hours after exposure but can begin up to a week after exposure.
Patients with Campylobacter infections generally present with diarrhea and fever 2 to 5 days following exposure.
Patients with STEC infections generally present with severe bloody diarrhea or non-bloody diarrhea and abdominal pain, but little to no fever 1 to 8 days (usually 2 to 5 days) following exposure.
Patients with Cryptosporidium infections present with watery diarrhea, vomiting, stomach cramps 2 to 14 days following exposure and symptoms may be intermittent.
Providers should obtain stool samples from patients with vomiting and diarrhea and test for bacterial and parasitic pathogens with a specific request for Cryptosporidium. Patients infected with E. coli O157:H7 are at increased risk for developing hemolytic uremic syndrome following antibiotic exposure. Do not prescribe antibiotics to patients with bloody diarrhea until STEC have been ruled out.