Heartworm and Tickborne Diseases

Here are some answers to frequently asked questions about Heartworm and tickborne diseases that will help you make informed choices when it comes to testing for disease and preventing illness in your pets

What is Heartworm Disease? Heartworm disease is the result of a dog being bitten by an infected mosquito. The heartworm larvae is transmitted through the mosquito bite and travels to the animal's heart where it develops into a 35cm/14" long, slender worm. If not treated, adult worms will interfere with blood flow, damaging the animal's main pulmonary arteries and heart.

Symptoms of heartworm disease include coughing, shortness of breath, intolerance to exercise, nose bleeds, lung clots, non-infectious pneumonia, compromised immune system, and kidney and joint inflammation among others. In its worst form the animal develops Caval Syndrome, which is an infestation of up to 100 or more worms, leading to shock and death if not treated immediately.

Can Cats get Heartworm?

Yes. There is a difference however, between canine and feline heartworm disease. Heartworm is a parasite of the dog and the worm is “programmed” to travel to the heart where it matures. Because a cat's internal make-up differs from a dog, the heartworm can become “lost” while using a map of the dog to find its way to the heart. The worm can end up anywhere in the cat including the abdomen, the brain, the lungs, or the heart. Canine heartworm disease is a heart disease, whereas feline heartworm disease is primarily a lung disease, caused by an inflammatory reaction in the cat generated from the worm's presence.

Symptoms of feline heartworm disease include respiratory distress, chronic coughing and vomiting, and inflammation of the kidneys, gastrointestinal tract and nervous system. Feline heartworm disease can result in sudden death.

Can Heartworm be transmitted from my pet to my family? Heartworms are rarely transmitted from dogs to humans. In fact, only 81 cases of heartworm in humans were reported from 1941 to 2005

How often should my pet be tested for Heartworm?

Dogs should be tested every year at the start of warm weather (usually April or May). A simple blood test which we run in-house, called a “4DX”, will tell us whether or not your companion is infected. This is an extremely comprehensive test, covering Heartworm, Lyme Disease (transmitted by ticks) and two other tickborne diseases called Anaplasmosis and Ehrlichiosis. Cats are not typically tested yearly.

If my pet tests positive for Heartworm, how is it treated?

Dogs are treated with heartworm adulticide therapy, which is a medication that kills adult heartworms. Depending on the level of disease in the dog, other treatments may be required for complications caused by this disease.

If a positive cat does not appear sick, the American Heartworm Society recommends attempting to wait out the worm's two to three year life span and simply monitor chest radiographs every six months. Heartworm adulticide therapy is dangerous for a cat and is considered a last resort in treatment.

How can Heartworm infection be prevented?

Annual heartworm testing (in dogs) followed up with a standard six or seven month course of heartworm preventative medication (in dogs and cats) is the best defense against heartworm infection. There are several medications available that prevent heartworm infection among other diseases. Discussing your pets environment and lifestyle with your vet will help you narrow down which prescription medication is best.

Heartgard: A flavoured chewable “treat” administered once a month. This treats heartworm, roundworm and hookworm in dogs.

Spectra: A flavoured chew administered once a month. This treats Heartworm, Roundworm, Hookworm, Whipworm, fleas and ticks in dogs.

Milbemax: A pill administered once a month. This treats heartworm, hookworm, roundworm and tapeworms in cats.

Revolution: A topical solution for dogs and cats, applied to the skin once a month. In dogs this medication treats: heartworm, fleas, most ticks, ear mites, sarcoptic mange, and roundworm. In cats this medication treats: heartworm, fleas, ear mites, roundworm and hookworm.

Ticks that infect animals and humans with Lyme Disease are present in the city of Winnipeg and surrounding areas. Their extremely small size can make them hard to detect. Here are some commonly asked questions regarding ticks.

What are tickborne diseases and why should I be concerned?

There are three common tickborne diseases we test for in Manitoba: Lyme Disease, Anaplasmosis and Ehrlichiosis. All three are covered in our 4DX Heartworm test and all three are transmissible to animals and humans. People are not infected by their pets directly, however animals can introduce unfed, infected ticks to the household. It is possible for partially fed ticks to detach from their animal host and reattach to people.

Lyme Disease: Caused by a bite from the tiny “deer tick” or the “black legged tick”. Unlike wood ticks, which are larger and do not transmit Lyme Disease, these ticks are only slightly larger than the head of a pin and are very easy to overlook. Once bitten, it takes approximately 24 hours of active feeding (blood sucking) to transmit the organism that causes Lyme Disease.

Symptoms which usually develop 2-5 months after a bite can include fever, swollen lymph nodes, joint swelling, and shifting leg lameness. Non-erosive polyarthritis is reported as the most common clinical sign. The limb closest to the tick bite is usually the first to exhibit signs of disease, then it may shift to another limb. A red, bulls-eye lesion is seen in 80% of people exposed to lyme disease and a similar lesion can appear in dogs. Less common, but far more severe symptoms include kidney disease, kidney failure, loss of appetite, vomiting, weight loss, and lethargy. Many patients die or are euthanized because of kidney failure. Other uncommon, but reported disorders include rheumatoid arthritis, myocarditis-induced arrhythmias (heart disease), focal meningitis and encephalitis (brain disease). Lyme Disease Treatment can be attempted with a combination of anti-inflammatory and antibiotic medication. Improvement is usually noted within 24 to 48 hours, with antimicrobials given for a minimum of 30 days.

Canine Anaplasmosis: Is usually a mild tickborne disease with no clinical signs, but can occasionally cause an illness called Infectious Cyclic Thrombocytopenia (low platelets and bleeding tendencies). Many times this disease can be associated with Lyme disease or Ehrlichiosis. Possible clinical signs include anorexia, lethargy, weight loss, fever, pale mucous membranes, nose bleeds, petechial hemorrhage, and swollen lymph nodes. Antibiotic treatment is usually successful if started promptly.

Ehrlichiosis: As is the case with Anaplasmosis, in most cases this disease is mild causing lameness, transient fever and malaise. Occasionally it can lead to lymphoma (cancer of the lymph nodes). Antibiotic treatment is usually successful if started promptly.

How can I protect my dog from tickborne diseases?

Testing for disease with the 4DX Snap test is the first step. Providing your dog with tick control medication is the second step. Vaccinating your dog annually against Lyme Disease is the third step.

If the unfortunate event arises where we have a positive result on the 4DX snap test, the doctor will be in contact with you on the steps needed moving forward.

What do I do if I find a tick on my dog?

Don't panic. If your dog is on tick prevention and has received the Lyme vaccine, they are as covered as you can be. You should remove the tick if you find one but most tick medications will kill the tick and they will fall off on their own. For this reason, you may find very little to no ticks on your dog while using the prevention. If a dog has become infected by a tick, it will usually take about 6 months to show up on any blood tests such as the 4DX snap test. Since it can take so long to get a positive result, it is important to test your dog yearly.

What tick control medication should I use on my dog?

Spectra: a flavoured chew administered once a month. This treats: Heartworm, Roundworm, Hookworm, Whipworm, fleas and ticks

Simparica:a flavoured chew administered once a month. This is for the treatment and control of tick and flea infestations

Revolution: a topical solution for dogs and cats, applied to the skin once a month. In dogs this medication treats: heartworm, fleas, ticks, ear mites, sarcoptic mange mites and roundworm.

None of the above mentioned products will control or protect from ticks 100%