We want every calf to be healthy, but unfortunately scours can occur.
It is important to keep an eye out for calves with loose stools, so you can intervene early.
Cryptosporidiosis is one of the diseases that sick calves can spread.
In addition, humans can catch Cryptosporidiosis, said Dr. Jeff Bender, UMASH Director, DVM, University of Minnesota. UMASH, or the Upper Midwest Ag Safety and Health Center, is asking livestock producers to use good sanitation to avoid this waterborne disease.
There are many zoonotic intestinal diseases to consider on livestock farms. These include bacteria and parasites.
One of the most recently identified diseases is Cryptosporidiosis or “crypto.”
Discovered in the early 1900s, crypto was considered insignificant until associated with gastrointestinal illness in the early 1980s. It is an acute enteric (intestinal) disease and is generally associated with water.
Crypto protozoa can be classified into two main types: human (Cryptosporidium hominis) and animal-related (Cryptosporidium parvum), Bender said.
Both can cause people of all ages to experience diarrhea, stomach cramps, nausea and vomiting. Some people need hospitalization to treat dehydration.
Crypto has an outer shell that makes it tolerant to chlorine, but boiling water kills the protozoa, according to the Center for Disease Control and Prevention (CDC).
In an infected animal, the protected oocysts are shed in the stool. If the infected stool is ingested, crypto can easily spread to other animals in the herd.
An infected person or animal may shed 10-100 million crypto protozoa in a single bowel movement.
Swallowing as few as 10 crypto protozoa can cause infection.
Cryptosporidium is a leading cause of waterborne disease in humans in the U.S., according to the CDC.
In 2018, Minnesota had 532 cases of human cryptosporidiosis reported to the Minnesota Department of Health. Ages of patients ranged from 3 months to 92 years. Children 10 and under accounted for 22 percent of the cases, and 60 percent of the cases occurred during July through October.
Five recreational water outbreaks occurred in 2018, leading to 108 cases. Three occurred at campgrounds in Goodhue, Le Sueur and Waseca counties. One was associated with a splash pad in Carver County. One occurred at a municipal pool in Nicollet County.
These cases show the importance of using “swimmer diapers” for children that are not potty-trained.
Two outbreaks were associated with animals for eight cases in Rock and Stevens counties in 2018.
Seven outbreaks were due to person-to-person transmission at child care centers for 30 cases. These outbreaks occurred in Blue Earth, Kandiyohi, Carver, Fillmore and Stearns counties, according to the Minnesota Department of Health.
Calves can be exposed to crypto right after birth – especially when born in pens with contaminated manure. About a week after birth, the protozoa have caused enough disruption in the gut to create observable illness (e.g. scours). Calves may display scours ranging from “pudding-like to watery.”
Most cases of crypto occur in calves less than a month of age. Older calves are more resistant but can still pass the protozoa in their manure.
There are no effective treatments or vaccines for crypto in calves, according to an SDSU Extension bulletin, “Cryptosporidiosis: A Potential Source of Illness in Calves and People Alike,” by Dr. Russ Daly, DVM, SDSU Extension Veterinarian, State Public Health Veterinarian.
His paper was recently distributed with information from UMASH.
Agritourism events where children are petting or handling baby calves and not washing their hands can lead to crypto infections, Bender said.
Families with young children, those who are immunocompromised, and the elderly may have significant problems with crypto, he said. Seeing a cute young calf and not understanding about scours or zoonotic diseases also increases the risk for young children.
Bender recommends four practices for producers to protect themselves, their livestock and others from Cryptosporidiosis and other diseases:
1) Be aware of children in the barn, and organisms that can be passed to children.
2) Keep kids, especially younger children with poor hand washing skills, away from calves with scours.
3) Provide an area to wash hands thoroughly with soap after working with calves.
4) Practice good biosecurity. Keep ill calves separated from healthy calves. Engage your veterinarian on good practices and protocols to reduce transmission.
“Usually Cryptosporidiosis lasts for a week to two weeks,” Bender said. “There are a number of zoonotic diseases that can cause (watery) diarrhea in humans. Cryptosporidiosis is just one of them.”
Crypto is diagnosed by examining stool samples, and the parasites may not be shed every day. Some patients may need to give three samples collected on three different days to make sure there is a negative test for crypto.
According to the CDC, health care providers may need to request testing for crypto, as routine parasite testing may not include it.
For more information, visit the Minnesota Department of Health and the Center for Disease Control and Prevention, and http://umash.umn.edu/biosecurity.
Graphic: Reported outbreaks of Cryptosporidiosis in Minnesota by transmission route, 2009-2018.
Graphic: Average yearly incidence of reported Cryptosporidiosis in Minnesota by county, 2009-2018.