How to deal with West Nile threat to horses, humans

RBC I Rio Blanco County’s first confirmed case of West Nile Virus was announced last Tuesday with the news that a horse on County Road 7 (Strawberry) had died following a bout with the virus.
“West Nile Virus is a disease that threatens the health of humans, horses and other animals; this is the time of year we are most likely to see it reported in horses,” said Colorado State Veterinarian Dr. Keith Roehr. “It is difficult to project how many cases we may see in the coming months.”
The transmission of the disease varies from year to year and depends on a number of factors including mosquito numbers. The virus can be carried by birds, specifically of the corvid family, such as crows, ravens, magpies and jays, said Colleen Zufelt, director of the Rio Blanco County Department of Public Health and Environment. The virus is then spread locally by mosquitoes that bite those birds. The mosquitoes can then pass the virus to humans and animals.
Infected horses may display symptoms including head tilt, muscle tremors, stumbling, lack of coordination, weakness of the limbs or partial paralysis, Roehr said.
The clinical signs of WNV are consistent with other important neurological diseases such as equine encephalitis, rabies and equine herpes virus; therefore it is important to work with your veterinarian to get an accurate diagnosis through laboratory testing.
Horse owners should also consult their private practicing veterinarian to determine an appropriate disease prevention plan for their horses.
Vaccines have proven to be a very effective prevention tool. Horses that have been vaccinated in past years will need an annual booster shot. However, if an owner did not vaccinate their animal in previous years, the horse will need the two-shot vaccination series within a three- to six-week period.
In addition to vaccinations, horse owners also need to reduce the mosquito populations and their possible breeding areas. Recommendations include removing stagnant water sources, keeping animals inside during the bugs’ feeding times, which are typically early in the morning and evening, and using mosquito repellents.
“It is important to protect your horse through the West Nile Virus vaccination and good management practices,” Roehr said.
“Individuals can protect themselves by wearing light-colored clothing that has long sleeves and pants; and use sprays containing DEET to repel the mosquitos, Zufelt said. “Most people will not become ill or will only have flu-like symptoms.
“About 20 percent of those infected may suffer from headache, fever, muscle aches and vomiting,” she said. “More serious illness could include brain swelling, meningitis, vision changes, paralysis or even death. People with symptoms should seek medical attention immediately.”
There is not currently a West Nile Virus vaccine for humans, Zufelt said.
In the United States, most people are infected from June through October. Seasonal outbreaks often occur in local areas that can vary from year to year. Many factors impact when and where outbreaks occur, such as weather, numbers of mosquitoes that spread the virus, and human behavior.
“Because our Rio Blanco County residents are active and outdoors a lot, it is important to take steps to prevent mosquito bites.” said Dr. Kellie Turner of Pioneers Medical Center in Meeker. “Take the time to do the following tips and it will decrease your risk against West Nile Virus:”
Use insect repellents with DEET when you go outdoors; wear long sleeves and pants during dawn and dusk; install or repair screens on windows and doors; Use air conditioning, if you have it; and empty standing water from items outside your home such as flowerpots, buckets, old tires and kiddie pools.
Approximately 20 percent of people infected with the virus will develop symptoms such as fever, headache, body aches, joint pains, vomiting, diarrhea, or rash. Less than 1 percent will develop a serious neurologic illness such as encephalitis or meningitis (inflammation of the brain or surrounding tissues). About 10 percent of people who develop neurologic infection due to West Nile virus will die.