West Nile Symptoms in a Dog

The lazy, hazy days of summer also bring out the buzzing and biting of mosquitoes. Those biting insects can transmit the potentially deadly West Nile virus to people and animals. While horses and birds are most often WNV victims, dogs can get sick if bitten by an infected mosquito or if they consume an infected bird or other animal. Most canines show few, if any, symptoms, but some dogs become quite ill.

If your apparently healthy dog tests positive for WNV exposure in a routine blood test, don't panic. Most positive dogs remain asymptomatic. The majority of dogs who develop symptoms of WNV are puppies, seniors, those who are already sick or dealing with compromised immune systems. In humans stricken with WNV, the disease causes encephalitis, or brain inflammation. A similar condition can affect dogs with WNV. There's no record of infected people spreading WNV to their dogs, or vice versa.

If your dog does come down with WNV, he's likely to appear weak and lethargic, possibly exhibiting muscle tremors and coordination problems. He might spike a fever and lose his appetite. Some affected dogs experience neurological symptoms, such as circling and head tilting. A dog might suffer convulsions or seizures. Since the incubation period for WNV in dogs can last months before symptoms appear and it is relatively rare in dogs, your veterinarian might not immediately consider WNV as the culprit; these symptoms resemble those of various conditions, which your vet might test for first.

Your vet conducts a blood test to diagnose WNV. If your dog tests positive and displays symptoms, your vet recommends supportive care and specific symptom treatment. Since it's a virus, antibiotics aren't useful in symptom management. Fortunately, affected dogs rarely die from WNV infection and most make full recoveries.

While an equine vaccine exists for WNV, that's not true for canines. The key to prevention -- for you and your dog -- is mosquito exposure reduction. That means staying indoors during primary mosquito feeding hours. That's early morning, dusk and into the night. Ask your veterinarian about topical mosquito repellents that are safe for dogs. Don't use repellents designed for people on your pet. Get rid of any standing water around your property, and avoid taking your dog for walks near water.