104 NEBRASKA CATTLEMAN February 2026 PEERS ZOONOTIC DISEASE RISKS DURING CALVING SEASON LINDSAY WAECHTER-MEAD, DVM, MS | EXTENSION EDUCATOR & DIRECTOR OF NEBRASKA BEEF QUALITY ASSURANCE, UNIVERSITY OF NEBRASKA-LINCOLN According to the Center for Disease Control and Prevention (CDC), zoonotic diseases are pathogens that can spread from animals to humans, leading to illness. The CDC reported 59 zoonotic outbreaks in 2017, causing more than 1,500 illnesses and three reported deaths. There are several different germs that have the potential to be zoonotic, with some more prevalent than others. The disease lists can be categorized in different ways, such as route of transmission, type of pathogen or production season. While it is important to familiarize yourself with all potential areas of concern, this article will focus on diseases that may be more commonly observed following contact with young calves. CRYPTOSPORIDIOSIS Cryptosporidiosis (crypto) is a common disease that causes severe, watery diarrhea in both animals and humans. Of the 59 outbreaks in 2017, cryptosporidium was the most common at 41 percent. Crypto is caused by a very small parasite called Cryptosporidium parvum, which can live in the environment for months. Once ingested by the animal, the parasite completes its life cycle in the intestines and is shed in the feces. Most infected calves’ age range is one to four weeks. Clinical signs include lethargy, weakness and diarrhea. Feces may contain bile, blood, undigested milk and mucus. It is important to remember calves may be infected without showing any signs. Supportive care (fluid therapy, nutritional support) is the only treatment. Crypto can be spread to humans through oral contact with contaminated soil, water or feces. Symptoms in humans are similar to those observed in calves. Zoonotic transmission often occurs during calving season when treating infected calves. Multiple outbreaks have been reported in veterinary hospitals and farms across the country. SALMONELLOSIS Salmonella is a widespread gram-negative bacteria that may cause diarrhea in young calves, with dairy calves being most prevalent. Infected cattle range in age from younger than one month to adult, with most patients lacking adequate colostrum intake at birth. Clinical signs may include fever, depression, diarrhea and swollen joints. In addition, carrier animals may not show any signs of illness. A human outbreak from contact with dairy calves infected with Salmonella occurred in 2018, leading CONTINUED ON PAGE 106 The CDC reported 59 zoonotic outbreaks in 2017, causing more than 1,500 illnesses and three reported deaths.
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