The Number Of West Nile Cases In Horses Is On The Rise

Jul 23, 2018

Mosquito pools in Box Elder, Davis and Uintah counties have been tested positive for West Nile Virus. State health officials are warning people to take precautions. Veterinarians are warning people to take precautions for horses and other animals.

July is the month when mosquito pools test positive for West Nile according to Karl Hoops, the Utah State University Equine extension specialist. In a few weeks, we will see birds test positive and shortly after humans and other animals.

“The way the disease is spread is when the virus is put into a bird, they become what we call an amplifying host,” Hoops said. “Their bodies allow that virus to replicate and get really, really concentrated within their blood. The mosquito can then bite them, suck out a small amount of that blood and then go bite a horse and then go bite a human. It then infects that mammal. Inside a mammal, when the virus gets in there it replicates, but we get sick a lot easier.”

The virus can’t replicate to the point where a mosquito can bite a mammal and then spread it to another mammal. Hoops said the disease has to be spread from bird to mosquito to mammal. That means you don’t have to quarantine your horses from other animals.

Hoops said the best way to prevent West Nile in horses is to vaccinate in about April or May. If you haven’t yet, he says it’s not too late. The vaccines aren’t 100 percent effective so Hoops says there are other precautions to take like removing stagnant water from tires and puddles.

How do you know if your horse does get the virus?

“Clinical signs in your horses you’re going to see a fever,” Hoops said. “A lot of people temp their horses every day. If they see a spike they’ll call their veterinarian. They start to stumble around a little bit, they don’t know where their legs and feet are, predominantly in the hind legs. You start to see muscle twitching in the muzzle and neck.”

In worst case scenarios Hoops said horses can’t get up which can lead to organ failure if they’re not up and moving. The best treatments are IV’s and anti-inflammatories. He said all cases should be reported to veterinarians.

According to the Utah Department of Health, the number of West Nile cases has risen from four in 2015, seven in 2016 and 35 in 2017. Hoops said this may be caused by people becoming more complacent about taking measures to prevent the virus.