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It’s that time of year again. As the weather warms, we are reminded of the lesser joys of living in the Hudson valley – mosquitoes and heartworms. Please be sure your pet is on heartworm prevention.

As you may remember, heartworms are, in fact, worms that live in the vessels that connect the heart to the lungs. They can invade the chambers of the heart itself and cause permanent heart and lung damage, which often is fatal. Mosquitoes transmit these worms, and while the highest incidence is in the southeast of our country, this is a national (and local) problem.

The problem starts when a mosquito bites an infected animal – typically another dog, but can also be a fox or coyote – and then bites an unprotected dog, thus giving them the worms. The worms migrate in the blood stream until they find their home in the heart, where they can live for 7-10 years!

While these worms are living, growing and multiplying in the dog’s body, they are often silently causing damage until the damage is irreversible. While sometimes the signs are detected (coughing, decreased appetite, labored breathing, etc.), they are often not detected until the disease is advanced. This is why testing (and preventing) is so important. If we can detect the disease early, we have better success in treating it.

Which brings us back to this time of year. We typically test in the early spring, as that is when many people are restarting their heartworm prevention. Ideally, you would give your preventative year-round to hopefully catch any unseasonably warm days where mosquitoes come out, but a lot of people do stop in the winter months. Testing is important to catch any “silent” infections, but it is also helpful prior to restarting prevention, as there is a risk of causing complications if you give heartworm preventatives to an already positive dog.

Another important note is that the life cycle of the heartworm – from the time a mosquito bites your dog to the time where they will test positive – is about 6 months. That means that if you adopt your dog from a high-incidence area, we will likely recommend rechecking the heartworm status 6 months from adoption, even if they were negative. This is also why puppies do not get tested right away – if they are too young, they will not have had time for the worm to grow and present a positive result on a test. (This is also why starting preventatives in young puppies is ideal – it will help protect them before they have a chance to even be infected).

Treating heartworm disease in dogs is expensive and has potentially severe complications, so routine testing and prevention are the keys to avoiding this deadly disease. The preventatives are extremely safe and effective, and it is much more affordable to prevent than to treat. Many animal hospitals offer oral, injectable and topical options.

A quick word on cats: Cats can get heartworm disease, but they are not the natural host, so often they are more resistant, or the adults will never fully grow. However, they can from time to time be infected and there is, unfortunately, no great test, nor is there any treatment. Heartworm preventatives do exist for cats and are highly recommended, especially if the cats go outside.

Should you have any questions, comments or concerns, please don't hesitate to contact us by phone at 845-876-6008, or by e-mail at [email protected].

Thank you for choosing us to be part of your pet's healthcare team!

With warmest regards,
Your friends at Rhinebeck Animal Hospital


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