Middlesex Veterinary Center

31 Stevens St.
Littleton, MA 01460






Heartworm Prevention - Dog & Cat Outside in Grass


Heartworm is a disease transmitted to dogs and cats by mosquitoes infected with the heartworm larvae and is potentially fatal to your pet.  When an infected mosquito bites the animal, the larvae are injected into the bloodstream and eventually develop into adult worms in the blood vessels of the lungs and heart.  If left untreated, the subsequent inflammation and clogging of the vessels in the heart and lungs will kill the dog or cat.  Treatment for this disease in dogs is potentially dangerous and expensive.  However, prevention is affordable and easy.

It is important for owners to realize that cats are also at risk for heartworm.  The disease is more dangerous in cats because it takes much fewer heartworms to lead to a fatal illness and there is currently no safe and effective treatment for cats.  However, prevention is also easy and affordable.

Heartgard Plus: 
This is a monthly chewable beefy flavor tablet that protects your dog and cat against heartworms and three common intestinal worms.  The tablets are given once per month according to the proper weight range and should be given year round. The active ingredient is Ivermectin.

This is also a monthly chewable heartworm and intestinal worm preventative for cats and dogs and is particularly effective against whipworms. For dogs (especially the herding breeds) who are sensitive to the active ingredient in Heartgard (Ivermectin) this is a good choice. The active ingredient in Interceptor is Milbemycin.

Heartworm/Lyme/Ehrlichia/Anaplasma Testing (4DX): 
We recommend performing this simple blood test on all dogs once per year to screen for potentially fatal heartworm disease and for three tick borne diseases.  No medication is 100% protective but if a pathogen should slip through we can identify and treat as soon as possible.

For more information, visit the American Heartworm Society website at http://www.heartwormsociety.org.