Can Dogs Get West Nile Virus?
West Nile virus rarely causes illness in dogs, but mosquitoes can still expose them. Here’s what dog owners should know about risk, symptoms and practical prevention.
Key takeaways
- Yes, dogs can be infected with West Nile virus through mosquito bites, but CDC describes West Nile disease in dogs as rare.
- The busy 2026 season is being tracked in people. No current source we found reports a 2026 rise in canine illness.
- Sudden weakness, tremors, stumbling, confusion, seizures or trouble standing need a veterinarian right away, whatever the cause.
- Never put a human insect repellent on a pet unless the label says it is for animals.
West Nile virus has had an early, active season in the United States this year. On July 1, CDC said the season had started early, with more infections reported by that point than in any year since 2004. Its current-year surveillance page was last updated September 22.
Those numbers describe people, not pets. They are a good reason to think about mosquitoes. They are not evidence that more dogs are getting sick.
So can your dog catch it? Yes. Is it likely to make your dog ill? The evidence says that is uncommon. Here is what is known, what is not, and what to do.
The short answer
Dogs can become infected when an infected mosquito bites them. CDC's surveillance and control guidelines state that West Nile disease in dogs is rare and that vaccinating dogs against it has not been recommended or practiced.
The Center for Food Security and Public Health at Iowa State University reaches a similar view in its veterinary fact sheet: dogs are readily infected, antibodies are relatively common in dogs where the virus circulates, but illness is uncommon. Sporadic sick dogs have been reported, including rare deaths, though most reported cases were not fatal.
Rare is reassuring. It is not the same as impossible.
What this year's numbers do and don't tell you
CDC's July statement reported at least 48 human cases as of June 30, 2026, 38 of them the severe neuroinvasive form. That early count is a signal about mosquito activity and human risk.
It does not translate into a canine case count. CDC's current-year page describes its data as preliminary and subject to change, notes that state and local health departments may have more up-to-date figures, and warns that surveillance of animals, birds and mosquitoes is done unevenly across the country. The absence of reported activity in your area, CDC says, should not be read as no risk.
For the most local picture, check your state or county health department's West Nile page.
Why most dogs don't get sick
West Nile virus normally circulates between birds and mosquitoes. People, horses and dogs are infected along the way, but CDC says there is no evidence that dogs or cats carry enough virus in their blood to become "amplifier" hosts that keep the cycle going. Veterinary references call dogs dead-end hosts.
The best-known experiment is small and more than 20 years old. In a 2004 study published in CDC's journal Emerging Infectious Diseases, researchers exposed four young adult hounds to infected mosquitoes. The dogs developed only low levels of virus in their blood, lasting roughly 12 to 60 hours, and showed no signs of illness. No virus was found in their mouth swabs.
Four healthy laboratory dogs cannot speak for every pet. The study helps explain why canine illness is rarely diagnosed. It does not prove that an older, very young or medically fragile dog would do as well.
The UC Davis School of Veterinary Medicine says dogs and cats are considerably more resistant to West Nile disease than horses, people and some birds, and that very young, very old and immunocompromised animals appear most likely to show illness.
So a healthy dog does not need an emergency visit after an ordinary mosquito bite. Watch for changes, and focus on prevention.
Signs that need a veterinarian now
When West Nile virus does cause illness in a dog or cat, it can affect the nervous system. Signs described by UC Davis and the Connecticut Department of Agriculture include:
- Fever
- Depression or unusual dullness
- Weakness
- Muscle spasms or tremors
- Stumbling or poor coordination
- Seizures
- Paralysis or inability to stand
None of these signs points to West Nile on its own. Many serious conditions can look the same, and UC Davis notes that blood tests are needed to diagnose infection. Don't try to work it out at home.
If your dog suddenly can't walk normally, collapses, has a seizure or seems confused, call your veterinarian or an emergency clinic right away. Calling ahead lets the clinic prepare.
Can a sick dog infect your family?
Not through ordinary contact, as far as current evidence shows. The Connecticut Department of Agriculture says there is no documented person-to-person, animal-to-animal or animal-to-person spread of West Nile virus. UC Davis likewise reports no evidence that people catch it from handling infected animals.
Connecticut still advises people who handle sick animals to wear gloves and avoid contact with their saliva. That is sensible with any dog showing sudden neurological signs, because the cause is not yet known.
Protect your dog the right way
Skip your own bug spray. EPA says not to use any repellent on pets or other animals unless the label clearly states it is for animals. UC Davis specifically warns that DEET products are not safe for pets.
Ask your veterinarian which flea, tick or mosquito product suits your dog, and buy the version made for your dog's weight. EPA stresses that weight matters a great deal in how much product a dog should receive.
Keep dog products away from cats. EPA has found that cats can be harmed by dog products because they are more sensitive to certain pesticides. In a mixed household, read every label twice.
Make your home less mosquito-friendly
Mosquito control starts with water. CDC recommends that once a week you empty and scrub, turn over, cover or throw out anything that holds water. Around a dog-friendly yard, that often means:
- Outdoor water bowls (refill with fresh water rather than removing them)
- Buckets, planters and flowerpot saucers
- Toys and kiddie or wading pools
- Birdbaths and trash-can lids
Install or repair window and door screens. CDC notes that the mosquitoes that spread West Nile are most active between dusk and dawn. On evenings when mosquitoes are heavy, a shorter walk or an earlier bathroom break is a reasonable adjustment. Your dog doesn't need to stay inside all season.
The bottom line
West Nile virus is having a notable year in people. In dogs, disease remains rare, and no current source we found shows that changing in 2026.
Clear standing water weekly. Keep screens in good repair. Use only pet-labeled products, chosen with your veterinarian. And treat sudden weakness, tremors or confusion as a reason to call the vet right away.
Mosquito season deserves attention. It doesn't deserve panic.
This article provides general educational information and is not a substitute for veterinary advice, diagnosis or treatment. If you are worried about your dog, contact your veterinarian.
Sources and further reading
- CDC — Current Year Data (2026), updated September 22, 2026
- CDC — July 1, 2026 newsroom release
- CDC — West Nile Virus Surveillance and Control Guidelines
- Austgen et al., Experimental Infection of Cats and Dogs with West Nile Virus
- Iowa State Center for Food Security and Public Health — West Nile Virus Infection
- UC Davis School of Veterinary Medicine — West Nile Virus
- EPA — Pet pesticide product safety
- CDC — Mosquito Control at Home
Health note: This article provides general educational information and is not a diagnosis or individualized veterinary plan. Contact your veterinarian about concerning signs or diet/medication decisions.
