Rabies: Be aware, be very aware
for Tri-State Livestock News
Rabies is a fatal virus that attacks the nervous system of its infected host and while most cases occur in wild small animals, occasionally the disease can also be passed on to family pets or livestock with the same unfortunate effects.
The disease is not commonly found in livestock such as horses, cattle, and sheep, but they can contract the disease after being bitten by a wild infected animal—typically a skunk.
According to Dr. Bleaux Johnson of West River Vet Clinic in Hettinger, North Dakota, rabies symptoms can often be hard to distinguish from other diseases that an animal may encounter.
He explained that “Neurological signs can vary from animal to animal.” He went on to say that symptoms could include abnormal vocalizations, excessive salvation, a desire to bite, and/or the animal going down and not being able to get up.
Other signs could include unusual differences in the animal’s behavior.
Dr. Tammy Winger-Merriman of Faith Veterinary Service in Faith, South Dakota, has also had a few elusive cases of rabies.
In one case Dr. Winger-Merriman encountered rabies in horses. She explained that they had “colic symptoms [and] didn’t want to eat or drink and acted painful.” The animals acted lethargic and had a very profuse nasal discharge.
Stereotypes around rabies sometimes causes the public to believe that animals go crazy with the disease, but in this case Dr. Winger-Merriman said “none of them [the horses] presented in rage or anything.”
Eventually the disease progressed which resulted in the horses’ swallowing muscles becoming paralyzed. They had to be euthanized. Their brain tissue test resulted in a positive reaction for rabies.
Full post-mortem exams are “a lot of time how we find rabies,” Dr. Winger-Merriman explained. A rancher might bring in a carcass to the vet to try to figure out why the animal died and through the vet’s protocol of sending tissues in they find out that the cause of death was rabies.
Because of the nature of the disease and the ambiguous symptoms, it is often hard to officially diagnose that the animal indeed has rabies without sending brain tissue into a lab to be tested.
Ranchers who suspect that their livestock or pets might be infected with rabies should contact their vet immediately so that they can take the proper precautions and make a diagnosis. Many vet clinics have a 24-hour emergency phone number that would work to contact them on weekends as well.
Because the symptoms of rabies are hard to distinguish from other diseases that commonly infect livestock, ranchers could wrongly assume that their animal has a respiratory disease, for example, and treat them for that instead of suspecting rabies.
Most livestock producers are accustomed to treating their animals for various diseases, but this could be very dangerous for the producer if the animal does indeed have the virus.
Administering oral medication when the animal is rabid is especially dangerous because the human would come into direct contact with the infected saliva which could cause them to become exposed to the disease through transmission through the skin or through an open wound on the human’s hand.
Rabies virus is relatively unstable outside of the host’s body, nevertheless if there is a confirmed case of rabies within livestock, it is important to closely monitor the rest of the herd to ensure that the virus hasn’t spread.
If the animal has died and the producer wants to test so see if the cause of death was rabies, they should contact their vet and then bring the carcass into the clinic. When transporting the animal, it is very important to avoid contact with it through using double rubber gloves and if the animal is small enough, using double plastic bags to transport it in.
At the clinic, the veterinarian will remove brain tissue to be sent in to a lab. Each state has different protocols as to how and where tissues are sent in to be tested.
In South Dakota brain tissue samples are sent to South Dakota State University’s Veterinarian Lab; however, if there was possible human exposure to the virus through the infected animal in the case, the samples are sent to the South Dakota Department of Health.
Veterinarians receive rabies vaccine and booster shots, similar to the vaccines that dogs and cats get, which means that they have a resistance to the disease and can take care of the tissue without concern.
If someone thinks that they may have come in contact with the disease it is important to seek medical attention immediately to stop the disease from progressing.
If caught soon enough, or if there is a chance that they have been exposed, people can undergo a series of shots to prevent them from getting the disease. Unfortunately for animals, by the time they are showing symptoms, it is too late for life saving treatment.
Rabies is spread through direct contact most commonly through the saliva of an infected animal—usually via a bite wound.
According to the Center for Disease Control, “when the rabies virus is introduced into a muscle through a bite from another animal, it travels from the site of the bite to the brain by moving within nerves. The animal does not appear ill during this time.”
Because the virus takes this pathway it can take anywhere from a few days to months for the virus to reach the brain and consequently for the animal to show symptoms.
Dr. Johnson explained that if a horse was bitten in the foot it would take longer for the virus to infect the brain because it has to travel further to reach the central nervous system. On the flip side, if the horse was bitten in the nose and infected with the disease, the virus would reach the brain more quickly.
The highest risk for humans to contract rabies is through their pets, which is why veterinarians strongly recommend that people vaccinate their dogs and cats and stay up to date on their booster shots.
“If you catch it early it, you might not be suspicious of rabies,” Dr. Johnson explained. In situations where a clear diagnosis cannot be initially reached, it is important to remember that rabies could be an option and to take the proper precautions.
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