Rabies detected in Brown County cow

St. Paul, MN: The Minnesota Board of Animal Health confirmed a Brown County Hereford heifer tested positive for rabies Sept. 8. Rabies is a preventable viral disease of mammals that affects the central nervous system, causing encephalopathy and death. The virus is most often transmitted through the bite of a rabid animal. This case highlights the importance of biosecurity, recognizing potential signs of infection, and personal protective equipment for those interacting with animals who may have an unknown infectious disease.

The owner noticed the heifer behaving oddly on Sept. 1, lying flat with its head down. A veterinarian observed the animal the same day, and the owner administered oral medication with bare hands. The following day, another veterinarian examined the animal and also gave oral medication without wearing gloves. On Sept. 3, a third veterinarian examined the animal and noted the cow had uncoordinated hind legs, was high-stepping, vocalizing, hypersalivating, and had a high temperature. The animal was humanely euthanized, and the head was removed for rabies testing at the Minnesota Department of Health (MDH) Public Health Laboratory on Sept. 8. 

“When we see livestock acting strangely, rabies may not be the first thing people think of to explain the behavior.” said Dr. Steve Kivisto, senior veterinarian leading the rabies program at the Board. “Given the severity of the disease, it’s better to assume an animal is infected until proven otherwise, and to be sure to take the proper precautions and use the correct personal protective equipment when working with a rabies suspect animal.”

In total, MDH recommended nine people obtain rabies post-exposure prophylaxis (PEP), as they may have been exposed to saliva from the infected animal. Rabies PEP consists of human rabies immune globulin (HRIG) and a series of rabies vaccinations given at specified intervals to prevent potentially exposed humans from developing rabies. The owner, the owner’s daughter, two minor children, two of the veterinarians that examined the animal, and three assisting veterinary technicians were recommended to seek PEP or rabies booster vaccinations. While a bite from an infected animal is the most common way that people are exposed to the rabies virus, it’s important to wear gloves and eye protection to prevent saliva from entering your eyes, nose or mouth or a fresh open wound when treating animals for an unknown neurologic illness.

“Consistent use of PPE when treating ill animals can help prevent exposure to rare illnesses such as rabies, said Dr. Stacy Holzbauer, State Public Health Veterinarian. “Additionally, MDH staff are available for consultation for any animal bite situation to assess rabies risk and provide recommendations for rabies prophylaxis.”   

The Board quarantined 13 cows, and more than 40 cattle will be kept under observation for rabies. A horse on the property was possibly exposed and is current on its rabies vaccinations and will be kept under observation along with three vaccinated dogs. Two unvaccinated barn cats with likely exposure were euthanized. 

Wild animals, especially bats, account for most of Minnesota’s annually reported rabies cases. Skunks and bats are the natural carriers of rabies in Minnesota. Numerous skunks were observed earlier this year on a neighboring plot of land owned by a relative that adjoins the area where the rabid cow was held. Less than 15% of rabid animal cases reported annually in Minnesota occur in domestic species; the most common being cattle, cats and dogs.

Clinical signs of rabies vary depending on the species of animal affected and the strain of the virus. Most animals show behavioral changes or neurological signs. Cats often become aggressive. Cattle may bellow frequently and have trouble walking and swallowing. Dogs may show a variety of signs ranging from aggression to difficulty swallowing and paralysis.

Once a domestic animal is exposed to the rabies virus, the amount of time until clinical signs develop (the incubation period) can range from 2 to 26 weeks, depending on the location of the bite and amount of virus that enters the body. Most domestic animals show clinical signs and die within 3 to 12 weeks. To help prevent the spread of the virus and to reduce exposure to other animals, the Board places all rabies exposed domestic animals that are not currently vaccinated under a 45-day – 180-day quarantine.

“Vaccination is very effective and directly saves the lives of exposed animals,” said Kivisto. “Vaccines are readily available for dogs, cats, ferrets, cattle, horses and sheep.” Vaccines are responsible for a substantial decrease in the number of human rabies cases in the past century.

If a pet animal bites someone, it must be confined and observed for 10 days. A domestic animal cannot transmit the rabies virus to humans or other animals until the virus is present in saliva, which occurs at the end of the disease process. Once the disease has progressed to this stage in domestic animals, the animal will show clinical signs of rabies infection within the 10-day observation period.

There are many steps pet owners and livestock producers can take to decrease the risk of rabies exposure and infection to domestic animals in Minnesota.

• Vaccinate animals under your care.
• Keep strays and wildlife (especially skunks and bats) away from pets and livestock.
• Do not approach unfamiliar or wild animals.
• Report stray animals or animals acting unusual to local animal control.
• Bat-proof your home.
• Avoid animals with abnormal behavior when hunting or trapping.
• Avoid contact with dogs and cats while traveling, especially internationally.

Numerous resources are available to veterinarians, human healthcare providers, animal producers and pet owners. MDH maintains the Animal Bites and Rabies Risk guide for veterinary staff and human healthcare professionals. The Minnesota Board of Veterinary Medicine offers this Rabies Vaccination Guidance Document for veterinarians and the public.

For all questions or concerns regarding possible pet or livestock exposure to rabies, call the Board at 651-201-6808. If you have questions or concerns regarding possible human exposure to rabies, call MDH at 651-201-5414.