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Safeguarding Your Best Friend - Tips and Tricks to Protect Your Dog from Canine Heartworm

May contain: grass, plant, animal, canine, dog, husky, mammal, and pet

As the weather warms up and spring turns to summer, it's important to remember that mosquitoes are not just a nuisance, but also a potential health threat to your pets. Aedes sierrensis, also known as the western treehole mosquito, is a particular concern for dog owners as it can transmit canine heartworm, a serious and potentially fatal disease in dogs.

 Treehole mosquitoes lay their eggs in the cavities of oak, bay, and other types of trees, as well as in discarded tires or containers with stagnant water and plant debris. If your property has a high density of trees, or you live adjacent to recreational areas and open spaces, your dog may be at greater risk of being bitten by these mosquitoes.

Although treehole mosquitoes do not transmit pathogens to humans, they can spread canine heartworm when they feed on infected dogs or coyotes. Once the mosquito is infected, it can transmit the parasite to other animals, including your pets.

Prevention is key when it comes to protecting your furry friend from heartworm. Regular check-ups with your veterinarian and preventative medications can help keep your dog safe. Be sure to consult with your veterinarian to determine the best heartworm preventative medication for your dog and follow the recommended dosage schedule.

In addition to medication, there are other steps you can take to minimize the risk of your dog being bitten by treehole mosquitoes:

  • Inspect trees for holes, including holes as small as half an inch that lead to cavities that may hold water. Contact a licensed arborist to discuss measures to prevent water from accumulating in tree holes.
  • Remove buckets, toys, tarps or other items holding water.
  • Check your gutters for clogs and standing water.
  • Contact the District for advice on reducing mosquito populations on your property.
  • For temporary relief from treehole mosquitoes in your backyard, try using one or more oscillating fans pointed away from seating areas. Treehole mosquitoes are weak flyers and have difficulty flying against the wind generated by fans.

Protecting your dog from heartworm is a year-round responsibility. Make sure you stay up to date with your pet's preventative medication and take necessary steps to minimize the risk of mosquito bites. Your furry friend will thank you for it!

For more information or to report mosquito issues call 707-285-2200 or visit

The Marin/Sonoma Mosquito and Vector Control District's programs and services are funded through property taxes and benefit assessments and are provided to all residents in Marin and Sonoma counties at no additional charge. 

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