West Nile Virus

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West Nile Virus is commonly found in mosquitoes in Yakima County. Learn how to protect yourself and your family.

What is West Nile Virus?

West Nile Virus (WNV) is a disease transmitted to humans and animals through the bite of an infected mosquito. While many people infected with WNV do not experience symptoms, it can cause serious illness in some individuals, especially those with weakened immune systems or underlying health conditions.

How Does it Spread?

West Nile Virus (WNV) is a virus spread mainly by mosquitoes. When mosquitoes bite birds carrying the virus, they can become infected. These mosquitoes can then bite humans or other animals, transmitting the virus. WNV cannot be spread directly from an infected animal or person to another animal or person.

Who is at Risk?

People who work outside or participate in outdoor activities are more at risk of getting WNV because of greater exposure to mosquitoes. People over the age of 60 years and people with certain medical conditions, such as cancer, diabetes, hypertension, and kidney disease are at greater risk of serious illness if they become infected with WNV.

Symptoms of West Nile Virus

Most people (about 80%) who are infected with WNV do not show any symptoms. However, those who do develop symptoms may experience:

• Fever
• Headache
• Body aches
• Joint pains
• Vomiting
• Diarrhea

In severe cases, WNV can lead to neurological illnesses, such as encephalitis or meningitis, which can include:

• High fever
• Neck stiffness
• Stupor
• Disorientation
• Coma
• Tremors
• Seizures
• Paralysis

If you develop symptoms of the virus after being bitten by a mosquito, contact your healthcare provider immediately.

How can I Protect Myself Against WNV?

Here are some steps you can take to protect yourself and your family from mosquito bites and reduce the risk of WNV:

• Prevent Mosquito Breeding:
  • Remove standing water from around your home where mosquitoes can breed. This includes flowerpots, gutters, pet water dishes, and discarded tires. 
  • Replace water in birdbaths, fountains, and your pets' water dishes at least twice a week.
• Install and Repair Screens:
  • Ensure that doors and windows have tight-fitting screens to keep mosquitoes out of your home.
• Wear Protective Clothing:
  • Wear long-sleeved shirts, long pants, and socks when outdoors, especially during dawn and dusk when mosquitoes are most active.
• Use Insect Repellent:
  • Use EPA-registered insect repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus, or para-menthane-diol on exposed skin. Always follow the application directions on the labels.
  • Apply permethrin (a pesticide that kills mosquitoes) to clothes and gear to prevent mosquito bites. Permethrin kills mosquitoes when they land on your clothes. It lasts through several washes after it is applied. Do not apply it directly to skin.
• Stay indoors at dawn and dusk, if possible, when mosquitos are the most active.

West Nile Virus and Animals

West Nile Virus can infect pets such as dogs and cats, but it is rare. However, it can cause serious illness in horses, mules, and donkeys. While most horses that become infected will not get sick, about 1 in 3 horses infected will die. To protect your horse, ask your veterinarian about the West Nile Virus vaccine. For more prevention tips, read our West Nile Virus in Horses Flyer.