Heartworm disease is a very frustrating condition. The reason this disease is so frustrating is because it can be extremely deadly, but is so easily preventable. It is heartbreaking to see an animal suffering from heartworm disease when it could have been avoided by simply giving them one pill a month.
Heartworm disease, which is caused by an organism called Dirofilaria immitis, has been found in all 50 states. Infection with heartworm is more common in the southern states. In areas where heartworm is considered endemic nearly 100% of unprotected dogs are infected. Even though this disease occurs more in the southern states, the American Heartworm Society reports that in 2007 for most of Minnesota an average of 6-25 cases of heartworm disease were seen per veterinary clinic. In the more populated Twin Cities area, an average of 26-50 cases were seen per veterinary clinic.
All it takes to contract this deadly disease is one bite from an infected mosquito. When the mosquito bites the target animal, it injects an immature heartworm. This immature heartworm then develops into an adult in the target animal in about 6 months. Once the heartworm is an adult, they are able to produce baby heartworms. While in the body these worms live in arteries in the lungs and occasionally in the right side of the heart. As the heartworms multiply they cause multiple problems including heart failure. Signs that your pet may be infected with heartworm include coughing, lethargy (tiredness), weight loss and difficulty breathing. There is treatment available for dogs who are suffering from heartworm disease, but the treatment poses its own risks and it can take anywhere from one to two months to consider an infection cleared. Unfortunately there is no approved treatment for heartworm in cats. Luckily, for unknown reasons, cats are inherently more resistant to infection with heartworm and are occasionally able to spontaneously rid themselves of a heartworm infection.
Current recommendations from the American Heartworm Society are to provide heartworm medication for all dogs. In Southern areas of the United States continuous, year-round prevention is recommended. For Northern states, such as Minnesota, heartworm preventative is recommended from May thru October. However, it is important to speak to your veterinarian about an appropriate heartworm regimen for your pet because an unseasonably warm Spring or Fall may necessitate prevention prior to May or later than October. It is also important for cats to receive heartworm preventative in areas where heartworm is considered endemic (southern states) or in areas where cats have a lot of exposure to mosquitoes. It is also noteworthy that indoor cats are also susceptible to heartworm infection as mosquitoes can easily come into a house in the summer months. Speak with your veterinarian to see if heartworm preventative is recommended for your pet. Preventing heartworm disease is easy, unfortunately treating it is not. Visit the American Heartworm Society's website for more information on heartworm and the most up to date recommendations on heartworm prevention.