Heartworm Facts

What is heartworm?
Heartworm is exactly that… a worm that goes into the animal’s heart!

Mosquitos transmit Heartworm in dogsHow does a dog get heartworm disease? It is transmitted by infected blood sucking mosquitos. The microscopic larvae that the mosquito injects into the animal’s skin then matures into adult worms in approximately 6 months. The adult worms then continue to reproduce and the dog can transmit heartworm to other dogs with the help of a mosquito.


What happens when an animal gets heartworm disease?

If a dog becomes infected with heartworm, hopefully it will be detected by a simple blood test before it gets to be life-threatening. If not, the animal may develop a cough, inability to exercise and or weakness. In severe cases, an animal may actually die suddenly from heartworm infestation.

Can cats get heartworm disease?
Yes, although it is quite uncommon. In many cats, it is also a single sex worm that infects them. Cough as well as sudden death can be the only symptoms.

Can heartworm disease be prevented?
Heartworm disease can be prevented with a medication that kills any larvae that have been injected into the animal within the last thirty (30) days. It is “retroactive” treatment which prevents the larvae from becoming adults and causing any clinical signs.

We recommend heartworm to be given during the months that mosquitos are most likely to be present (April to December). With crazy New England weather patterns, there may be an occassional mosquito during even frigid winter months. Some clients choose to give their pet preventative year round so as to not forget about it when the spring comes. Most animals can tolerate the medication without any problem. Some animals may have other conditions such as epilepsy or cancer should consult with their veterinarian before administering the medication. Also, if your animal develops any vomiting, diarrhea or other abnormal sign, contact your veterinarian.

Should my cat be on heartworm preventative?
At this time, we do not recommend routine preventative for cats.

Who is most at risk for heartworm disease?
Any dog that lives in an area that has mosquitos (essentially everywhere!) is at risk for heartworm. Areas that have mosquitos year round such as the southern United States are somewhat higher risks. Many of our animals do travel a lot (lucky dogs) and we also have a number of dogs in this area that have been adopted from Puerto Rico and other islands that can act as reservoirs for heartworm disease in not tested.

How often should my dog be tested?
Dogs should be tested once yearly if they are on seasonal heartworm preventative, ideally before preventative is started. If an animal has been getting heartworm preventative EVERY month year round, then it is reasonable to test every other year. No medication is 100% effective, hence the need for testing routinely. With routine testing, we can detected cases of heartworm before it causes symptoms.

What does the test look for?
The simple blood test detects presence of adult worms by detecting antigen or “reaction” to the presence of adult worms.

Can heartworm be treated?
In most cases, heartworm disease can be treated with a special injectable medication. In some cases, an animal may not be treated due to other pre-existing medical condition. Each case is analyzed individually with other blood tests as well as radiographs and possibly an ultrasound.