Vet Corner

Heartworm disease

Heartworm disease is a serious, life-threatening disease in cats and dogs.

Life cycle: Mosquitos transmit the heartworm microfilaria when feeding (blood transmission) from one infected animal to another. The larvae mature into adult worms in the heart and lungs of the host animal. The adult worms then reproduce, creating microfilariae about 6-9 months after the initial mosquito bite. Dogs are more susceptible to infection than cats.

Signs of Heartworm disease: Often clinical signs are not recognized in the earlier stages of the disease. As the number of heartworms increase over a period of time (months to years), signs may appear and are different for dogs and cats. Dogs often show a mild persistent cough, exercise intolerance, decreased appetite and weight loss. Cats often have non-specific signs that mimic other diseases and can include vomiting, gagging, lethargy, difficulty breathing and weight loss.

Testing for heartworm: A blood test looking for the “antigens” of the heartworm is usually the first test. Occasionally, additional testing will be needed. Ask your veterinarian for more information. Prevention of heartworm infection: There are many highly effective, easy, inexpensive and safe monthly (or less often) chewable or topical preventatives for heartworm. A veterinarian must test for heartworm prior to starting many of these products and should be consulted about what prevention is best for your pet. It is imperative that you stick with whatever prevention plan you decide on.

Treatment if your dog or cat is infected with heartworm disease: There are a few treatment options for dogs; however, they are all lengthy, taking several weeks, expensive and with significant risk to the dog. There is no approved treatment for cats. This is why prevention is key!

What CHS is doing to help prevent the spread of heartworm disease: We have begun testing all dogs that come into CHS for heartworm disease with a simple blood test. Any dogs that are transported from other areas are tested prior to travel, and those that are positive will not be brought to CHS. A special thanks to IDEXX laboratories, who have given us a huge discount on the cost of the tests. Without their help, we would not be able to afford to do them. All CHS dogs and cats are given revolution, a topical flea and heartworm preventative, during intake as well (and have been for years). It is recommended that you have your new pet (from wherever) tested six months after adoption (if already tested), and annually if already on preventatives.

References: http://www.heartwormsociety.org/pet-owner-resources/heartworm.html, and
http://oregonvma.org/care-health/heartworm-disease