House Springs Animal Clinic, PC

PO Box 715
House Springs, MO 63051


Heartworms                                   No Description

Heartworms are 12 to 18 inch long worms that live in the right side of the heart, as well as the blood vessels in the lungs.  They are spread by mosquito bites.  From the time the mosquito bites a dog bringing baby heartworms, it takes 6 to 7 months for the worms to grow to adulthood.  Because the test only detects adult female worms, we don't test dogs younger than 6 months of age, or we will get a false negative test.  Heartworms cause much damage to the blood vessels in the lungs and the heart by causing inflammation and partial obstruction.  Symptoms are heavy breathing, coughing, getting out of breath easily, weakness, and weight loss.  Severe infections can be fatal, although a dog is usually sick for quite a while before dying.  It is much easier to prevent heartworms by giving once-a-month heartworm preventive than to wait until a dog is sick with heartworms to treat.  Treatment can be risky, especially in sick dogs, as the treatment is an arsenic (highly toxic) drug. Once the worms die, they remain in the heart and pulmonary arteries until the body slowly breaks them down and removes them.   While this is occurring, the dog is at high risk to get emboli (clots) in the lungs.  We follow the guidelines set by the American Heartworm Society by requiring a heartworm test before a dog starts monthly heartworm preventive (unless it is less than 6 months old).  We recommend annual heartworm testing for all dogs, even if on preventive year-round, because there is still a slight chance that a dog may get heartworms.  It is best to catch heartworms early, before a dog is very sick, to treat the heartworms.

Heartworms are very common in Jefferson County and the House Springs area.  We have had many positive tests, and have treated hundreds of dogs for heartworms over the years.  The great majority of dogs treated for heartworms survive, but there can be complications and even fatalities post-treatment, so, as mentioned, dogs, whether inside or outside dogs, should be on heartworm preventive year-round.  The heartworm preventive also treats some kinds of intestinal worms that are not spread by mosquitos.  People who give heartworm preventive just part of a year usually wind up missing some important months, when a dog can be bitten by mosquitos that carry heartworms. 

Cats can also get heartworms.  It is about one-tenth as common in cats as it is in dogs, and the symptoms in cats are somewhat different in than in dogs.  Cats can get respiratory problems that look like feline asthma, and they can also vomit and lose weight.  Cats can not be successfully treated for heartworms because the treatment is usually fatal in cats.  It is also a good idea to give monthly heartworm preventive to cats.  Please ask us about heartworm preventives for your cat. 

We have several types and brands of monthly heartworm preventives in stock, and you can also order from our on-line pharmacy.  You can read about them on our pharmacy website.  Please ask us, if you have questions.

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