Canine Heartworm Disease
One of the most prevalent and dreaded diseases for dogs, heartworm disease in canines can be dangerous and life threatening. By targeting the vital organs such as the heart, lungs and liver, heartworms invade your dogs system quickly and cause damage to tissue and organs. Caused by a parasite and transmitted by mosquitoes, heartworm larvae enter the bloodstream and are transported to the rest of the body, eventually entering the heart. Once in the heart, the parasites make their way to the right ventricle and rapidly multiply. Symptoms of Canine Heartworm: The first symptom usually seen in canines is a dry cough. This is usually because the parasites have worked their way into the lungs where they irritate the area and continue to multiply, affecting breathing. Dogs suffering from heartworms may also show low tolerance for physical activities and may be easily winded. These same symptoms may also be an indication of other conditions, which is why it’s always important to consult with a vet. Causes of Heartworm: Heartworms are caused by parasites transmitted into your dog’s blood by mosquitoes. The mosquito becomes a carrier for the parasite by biting other dogs or animals infected with the parasite and then transferring the disease to your dog. Dogs especially at risk for heartworm infection are those who live in areas with high numbers of mosquitoes. In the U.S., dog owners in the western states should be particularly proactive about taking preventative measures, but any dog in any state with warm seasons is at risk for infection. Prevention: Heartworm infection is very dangerous but extremely easy to prevent with a monthly dose of heartworm preventative. Such medications come in many different brands and can be purchased from your veterinarian. Methods of administration vary, but the most common form comes in a chewable treat, which contains drugs that destroy the larvae of the heartworm on contact before they travel to the heart. Doses are given based on the weight and size of your dog. Treatment: Treatment differs from prevention in that treatment addresses the dog already infected with heartworms. In these cases you are dealing with adult heartworms versus the parasite in the larvae form. Unlike the larvae, which can be easily killed, adult heartworms are difficult to exterminate. Currently the only product available for the treatment of adult heartworms is melarsomine dihydrochloride, or Immiticide. The infected dog will usually receive an intramuscular injection in the lower back muscles with the solution. Given in multiple doses, the goal is to gradually kill off the adult worms, as killing too many too quickly can cause circulatory shock. Your vet will choose the number of doses and duration of treatment based on his assessment of the severity of your dog’s infection. After treatment, the dog will need to be confined for roughly a month. This is to keep him quiet and reduce the chances of him running or playing, which would increase his heart rate and oxygen demand, and could lead to other embolism related problems. Post Treatment Concerns: Even after treatment some rare cases may still test positive for heartworms. This does not mean your dog still has the disease necessarily; it could be that it is just taking longer for everything to clear his system. To double-check your pet, he should be retested at 4 months, 6 months and possibly a year after treatment, to ensure that it was effective. In addition to this some enlargement of the heart is common after treatment. This can usually be seen on an x-ray and varies from dog to dog depending on the severity of the infection, health/age of the dog, and duration of the treatment. A recent Gallup survey of 18,000 veterinary clinics shows that only 55% of U.S. dog-owning households use a heartworm preventative. A similar survey of the same veterinary clinics also showed that more than 240,000 dogs tested positive for heartworm infection in 2009. Most owners would never knowingly put their pet at risk for such a disease, which is why it’s important to stay informed and be aware of the risks as well as the preventative measures. Heartworms are much easier and less costly to prevent than to treat, but even if you do have to put your dog through treatment he can still go on to lead a normal healthy life.
