Matter of the Heart

posted: by: Dr. Joanne Carlson Tags: "Clinic Specials" "News" 

Spring has sprung! With the onset of warmer weather we all urge to get outside, including our animal companions, and we are exposed to those pesky insects, mosquitoes. A major health concern for your pet is Heartworm disease. Although all warm-blooded creatures are susceptible to the disease, dogs are primarily affected. Male dogs have a four time greater risk of infection than females. Dogs, which live outside, are 4-5 times more likely to be infected than other dogs. Large dogs are more prone to the disease than small dogs. Hair coat types do not appear to influence the risk of disease.

The major way Heartworm disease is transmitted is via mosquitoes. There are over 70 species of heartworm-transmitting mosquito. Unfortunately the warmer winters we have been experiencing have resulted in more mosquitoes and more dogs contracting the disease. Female mosquitoes are the culprits. They bite a dog, which has baby heartworms (micrfilaria) in their bloodstream. These microfilaria develop within the mosquito and are capable of infecting another dog within 2 weeks. The mosquito then bites a susceptible dog and the infective microfilaria migrate through the skin and tissues for 100 days until they are young adults. The young adult worms progress into the blood vessels of the lungs and find their way into the heart. Thus, within about 6 months of getting bit by an infected mosquito, the dog has worms living in its heart and is shedding microfilaria within its bloodstream. Just one infected dog can lead to an epidemic. When that infected dog is taken to a neighborhood where owners do not give their dogs preventative medication, mosquitoes can rapidly spread the disease to other unprotected animals.

Depending on the number of adult heartworms (anywhere from 1-250), the dog will show varying degrees of signs. Most dogs do not show any signs despite infection. The most common signs are weakness, fatigue, chronic cough, loss of appetite and weight loss. These warning signs of disease will not be present until Heartworm disease has reached advanced stages. By that time, your dog may have already suffered irreversible damage to the heart, lungs, liver and kidneys.

Treatment for Heartworm disease is available, involving several different protocols depending on each specific case. Dr. Carlson would need to perform bloodwork, x-rays and other tests to determine the severity of infection and to determine which treatment route is best suited for your pet. Unfortunately, despite the best treatment, dogs may die from the disease.

Overall, the key to Heartworm disease is prevention. This is imperative. Prevention is much easier than dealing with the consequences of the disease. A yearly blood sample serves to ensure your dog is heartworm-free. Then a monthly preventative is prescribed, which is effective 100% if given all year round in preventing heartworm disease. These monthly pills are chewable or tablets, and also help to decrease intestinal parasites or worms. Please consult Dr. Carlson  for the best preventative for your dog.

Cats are susceptible to Heartworm disease but to a much lower extent than dogs. They tend to have 5-20% the infection rate of dogs and are usually without any signs. They frequently do not have any microfilaria and the adult worms have a shorter life span. There currently is not a very specific test. Indoor cats are more prone to infection, perhaps due to the outdoor cats developing immunity over time and exposure. There is a monthly preventative available. Dr. Carlson  can suggest appropriate prevention for your feline.