The snow shovels are packed away, the flannel sheets are off the bed and the heated water buckets in the barn are unplugged. Spring appears to finally be upon us! There are so many good things about this time of year, but it also means we must be aware of the danger parasites can present to our pets. Last month we looked at what we can do about fleas and ticks. This month we will discuss another threat — heartworm disease.
If you go back about thirty-five years or so, heartworm disease was one of the top killers of dogs in New Jersey. Then a drug was developed called diethylcarbamazine, which was a daily oral heartworm preventative. The incidence of heartworm disease dropped. However, stopping the medication for even a few days would leave a dog susceptible to the infection. A number of years later, ivermectin was created and its use as an anthelmintic was unparalleled. It could be used just once a month to prevent heartworms and because this was so much easier, the number of cases of heartworm disease dropped even more.
Clients often now question the need for heartworm prevention since heartworm disease is now much less common. The answer is that it is still vital to protect your pet for several reasons. The first can be summed up in one event — Hurricane Katrina. Many dogs were left homeless after that awful storm and rescue groups relocated them all over the country. Unfortunately, fifty percent of those dogs had heartworm disease. With those new sources of infection, mosquitos started transmitting heartworm and it is now present in all fifty states. A second thing that has occurred is that we are seeing many rescue dogs being brought up from the southern part of the United States, where heartworm disease is rampant. Again, with a source of infection, mosquitos (which should have been chosen over the goldfinch as our state bird) can spread the disease. In addition, coyotes and fox can carry and transmit heartworm. Luckily, by no means do we have an epidemic, but that is because so many owners are diligent in protecting their pets.
Heartworm disease is treatable but that treatment is not without risk. The medication, called Immiticide, does kill the heartworms quite effectively, but since those worms live in the heart and in the blood vessels leading into the lungs, when they die, they can cause fatal blood clots in the lungs. It is much better to prevent the infection in the first place. We have several safe and effective options for prevention. Heartgard is a chewable monthly tablet that also prevents roundworms and hookworms. Sentinel does all that, plus it controls whipworms and also kills flea eggs and larva, helping to prevent house infestations. A third option is Proheart 6. This is an injection that is given every six months and prevents heartworms as well as hookworms. Revolution is a topical application that is particularly useful in cats. Cats do get heartworm disease and since Immiticide is toxic to them, there is no treatment. Revolution prevents heartworm, roundworms, hookworms and kills fleas and ticks. It also kills ear mites and scabies.
If your pet is currently on heartworm preventative, kudos to you! If not, dogs need to be tested to make sure they are negative before starting the preventative. The test is a simple blood test that can also be combined with a test for several tick-transmitted diseases (lyme, ehrlichia and anaplasma). We can then discuss the best option for heartworm prevention to help your pet continue to have a happy and active life.
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