Skip to content
Mosquitos and Your Pet
M Duffy Jones, DVM posted:
Should you be concerned about mosquitos and your pets? The answer is yes. Mosquitos can cause serious problems for our pets, including transmission of heartworm disease, West Nile virus, and even allergic reactions for some.

Heartworm disease is by far the biggest threat pets face from mosquitos. There are many natural reservoirs for heartworm disease, including feral dogs, coyotes, and wolves. When a mosquito feeds from one animal with heartworms and then moves on to the next, it will inject the worm larvae into the next animal. The larvae then mature and migrate to the animal's heart and lungs. Once there, the worms cause damage to these organs. And if left untreated, they can lead to heart failure.

The good news is that giving your pet preventatives each month can significantly decrease his chances of contracting heartworms. Preventatives are very effective and we rarely see failures of these products when they are given correctly.

West Nile Virus
Mosquitos also carry and transmit the West Nile virus, which can be a devastating disease for pets. It can cause a loss in muscular control, difficulty walking, and anorexia. Testing for this virus is also very difficult. Many times the pets are already recovering by the time the testing is complete. There is a vaccine for horses. But as of right now, the vaccine is not approved for dogs and cats. The risk of contracting West Nile virus is directly related to how much time a pet spends outside. So, obviously, outdoor pets are at the greatest risk.

Allergic Reactions to Mosquitos
Mosquitos can also cause allergic reactions for some pets. In my practice, I see many pets that get just a few mosquito bites, and their ears will swell and they will lose much of their hair. This occurs the most around the head and neck, where the fur is typically shorter and where mosquitos have a better chance at getting to the skin to bite. Some allergic reactions to mosquitos can be very strong and cause lots of inflammation and swelling in our pets.

For West Nile Virus and allergic reactions, good mosquito control is the only way to help prevent these problems. In addition to keeping your pet inside during times when mosquitos are the worst, this can also include:
- hiring a service to spray for mosquitos
- setting mosquito traps in your yard
- making sure you don't have any standing water around for mosquitos to breed
- keeping your ponds and outdoor fountains treated to prevent mosquito breeding

There are some products that do help to repel mosquitos. But there are also some that claim to repel them and don't. Be sure to talk to your veterinarian so he or she can advise you about which products should work best, based on your pet's age, breed, and medical history.

What have you done to prevent mosquito problems for your furry friends?


William Draper, DVM, better known as "Dr. Will," is a well-known small animal practitioner in the Atlanta, GA area. He grew up in Inglewood,...More

Helpful Tips

Excellent website for information on parasites in dogs and catsExpert
I just conducted a seminar and hands-on demonstration on diagnosis of fecal parasites to veterinarians and technicians. An excellent ... More
Was this Helpful?
33 of 48 found this helpful

Report Problems With Your Medications to the FDA

FDAYou are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Learn more about the AVMA

WebMD Special Sections