Mosquito Bites Are the Cause of Dog Heartworm

By Chris Williams on June 15, 2015.

Asian Tiger Mosquito 
I’ve avoided giving my dog heartworm medication, but I just learned yesterday that heartworm is spread by mosquitoes. Now I’m worried because we had a very bad mosquito problem in our yard last year. Besides giving Roscoe the heartworm pill, what else can we do
? E.K., Tilton, NH

It’s true that mosquitoes are the only vectors of dog heartworm. Heartworm is present in every state and can be spread by over 30 different species of mosquitoes. The incidence of heartworm is more common where mosquitoes are more prevalent, especially along waterways and coastlines. The length of the mosquito season in a region also directly correlates with the number of heartworm cases.

Dog Heartworm Basics

Dog heartworms are parasitic roundworms that develop and reproduce inside a dog’s body, eventually causing illness and sometimes death if untreated.

Heartworms are spread when a female mosquito sucks blood from an already infected dog. Along with the blood, she ingests the tiny worm larvae, called “microfiliariae.” After developing in the gut of the mosquito, heartworm larvae are passed along to the next dog that the mosquito feeds on. Inside the dog’s bloodstream, the larvae mature into adult worms and migrate to the dog’s heart, lungs, and blood vessels where they mate and continue to produce more microfilariae.

A heartworm can grow to 12 inches long and can live up to 5 years. During this time, a female can produce millions of offspring. These microfilariae live mainly in the small blood vessels where they can block blood flow, primarily affecting the dog’s lungs and liver.

It can take a few years before dogs show signs of the infestation. Symptoms of heartworm disease include a soft dry cough, shortness of breath, fatigue, and nervousness. Have your vet check Roscoe for heartworms without delay.

Even indoor dogs have been known to get heartworm when mosquitoes find their way indoors. All it takes is one bite from an infected mosquito to infect a dog. Cats can get dog heartworm, too, but they respond very differently. They can become ill but the worms don’t complete development. In very rare cases, people have been infected with heartworm, but again the worms cannot complete development.

Heartworm and Mosquito Prevention

The best and most reliable way to protect your dog from heartworms is heartworm medication: pills, lotions, or injectables. Talk to your veterinarian for details. Of course, anything you can do to prevent mosquitoes in your yard is also a positive step towards preventing heartworm. If you had a mosquito problem last year, it’s possible that there are conditions on your property that allow mosquitoes to breed.

Check out the blogs below for mosquito prevention tips and then give Colonial Pest a call. We can inspect your property and can treat high risk areas in your yard to prevent mosquito development. Being proactive against mosquitoes will not only help protect Roscoe from heartworm, but will protect the rest of your family from human mosquito-transmitted diseases like West Nile Virus.

Photo credit: frankieleon / Foter / CC BY



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