WHAT YOU NEED TO KNOW ABOUT HEARTWORM DISEASE

Now that spring is officially in the air and summer is just around the corner, it is time to start thinking about heartworm disease prevention. Many of you have probably heard of heartworms and may have even had your pet tested for them, but you may not know the details about this potentially fatal disease and how it is transmitted. While heartworm disease is a very serious condition, it can be reliably prevented by giving your pet medication just once a month.

To talk to one of our veterinary nurses about heartworm disease and prevention, or to schedule your pet for a heartworm test, please contact our office at 303/779-5525. Heartworm testing requires collecting a very small blood sample from your pet, and the results are usually available within 10 minutes.

The following selections are reprinted with permission from the American Heartworm Society, an organization that is working to further heartworm disease research and public awareness. To read the full content that these excepts were taken from, please visit the American Heartworm Society's website at www.heartwormsociety.org and click on the Pet Owner Resources tab.

What is heartworm disease?
Heartworm disease is one of the major health problems of dogs in the United States and throughout the temperate and tropical areas of the world. As well as being found in dogs and other species, it is now being found in cats in ever increasing numbers. The disease develops when a pet becomes infected with parasites called Dirofilaria immitis that are transmitted through the bite of an infected mosquito. Dogs may be infected by a few or up to several hundred heartworms. Cats are similarly infected although usually by only a few worms. Heartworm infection often leads to severe lung disease and heart failure and can damage other organs in the body as well.

How is heartworm disease transmitted from one pet to another?
Adult female heartworms living in an infected dog or other host release their young, called microfilaria into the bloodstream. Mosquitoes become infected by the microfilaria while taking a blood meal from these infected animals. During the next 10 to 14 days, microfilaria mature to the infective larval stage within the mosquito. When the mosquito then bites another dog, cat or susceptible animal, the infective larvae exit the mosquito's mouth parts and are deposited onto the surface of the animal's skin. The infective larvae can then actively enter the new host through the fresh bite wound.

Inside a new host, it takes a little more than six months for the infective larvae to mature into adult heartworms. Once mature, heartworms may live up to five to seven years, and because of their longevity, each mosquito season can lead to an increasing number of worms in our pets.

How big is my pet's risk for heartworm infection?
Many things must be considered even if heartworms do not seem to be a problem in a local area. If owners travel with their pets to heartworm-endemic areas, pets will be at risk of infection. Heartworm disease is spreading to new regions of the country each year. Uncared-for dogs and certain wildlife such as coyotes, wolves and foxes can be carriers of heartworms. Mosquitoes blown great distances by the wind and the transportation of infected pets to different geographic locations all contribute to the spread of heartworm disease to areas that may have previously been considered heartworm-free. The best way for easy, safe prevention of heartworm infection is to administer a year-round heartworm preventive as directed by your veterinarian.

Why do dogs need to be blood tested before starting heartworm medication?
Before starting a preventive program, all dogs should be tested for heartworms. Giving preventives to dogs that have adult heartworm infection can be harmful or even fatal to the pet.

Adult heartworms produce millions of microscopic "baby" heartworms (called microfilaria) into the bloodstream. When you give a monthly heartworm preventive to a dog with circulating microfilaria, this can cause the sudden death of microfilaria, triggering a shock-type reaction. Even if your dog does not have this type of reaction, heartworm preventives do not kill the adult heartworms (although they may shorten the worms' life expectancy). This means an infected dog will remain infected with adult heartworms.

Unfortunately, as long as a pet remains infected, heartworm disease will progress and damage the heart and lungs, which can lead to life threatening problems. Giving heartworm preventives to heartworm-positive dogs can mislead an owner into thinking everything is all right, while within a pet, heartworm disease is worsening.

How often should I have my dog tested for heartworm infection?
Annual testing is recommended for several important reasons. First, many of us do not take our own medications as directed let alone medicate our pets. We're busy; we forget; we miss a dose here and there. Second, even if you never miss a dose there is nothing to prevent your dog from eating some grass and vomiting up the medication you just gave. Your pet would be without protection for an entire month. Third, if your pet accidentally became infected with heartworms, your veterinarian needs to detect it as soon as possible before irreversible heart and lung damage occur. Early detection and treatment are always best.

How often should I have my cat tested for heartworms?
Heartworm infection in cats is easily overlooked and harder to detect than in dogs. The preferred method for screening cats include the use of both an antigen and an antibody test. Your veterinarian may also use X-rays or ultrasound to look for heartworm infection. Your cat should be tested prior to starting a preventive, and annually thereafter. Remember, since there is no approved treatment for heartworm infection in cats, prevention is critical.

How do monthly heartworm preventives work?
Fortunately, there are many very effective once-a-month heartworm preventives available today. Some are chewable tablets and others are topically-applied solutions. Monthly heartworm preventives, because of their ease of use and effectiveness, have become the popular choice for prevention of heartworm disease. Unlike the daily products of the past, these compounds are capable of killing developing heartworm larvae and administering the preventive every month will effectively eliminate the chance of infection. Check with your veterinarian to see which product is right for your pet.

An important note to keep in mind is that monthly medications are quickly eliminated from a pet's system and do not continue to work for 30 days. Instead they work "backwards" to eliminate the larvae the pet acquired the previous 30 days, in essence, "de-heartworming" our pets each month; in many cases, these monthly preventives control other parasites too.

Source: American Heartworm Society. Frequently Asked Questions (FAQ). Retrieved March 5, 2010, from http://www.heartwormsociety.org/pet-owner-resources/faqs.html#q1