Heartworms, roundworms, hookworms, whipworms, fleas and ticks are just some of the parasites our pets are exposed to on a regular basis in SE Virginia . Parasites are offensive creatures that live off the host animal's tissues in order to survive. They may be blood suckers, fluid drinkers or nutrient thieves but the goal is the same; survive and perpetuate the species preferably without killing the meal ticket (the dog or cat host). The good news is that all these parasites can be prevented or controlled by prescribing to a preventative program outlined by the veterinarians at Pet Care Veterinary Hospital .

Most dog owners are familiar with heartworm disease and the need to give year-round heartworm preventative, but did you know that nearly half of surveyed pet owners fail to follow the veterinarian's recommendations? And did you know that heartworm disease also infects cats and ferrets, and that monthly heartworm preventatives also protects against the most common intestinal worms and depending on the preventative used can even control fleas? According to the American Heartworm Society, more that 250,000 dogs and 3,000 cats test positive for heartworm infection every year. Mature adult heartworms produce microscopic larvae (baby worms) which circulate in the blood and are picked up and then carried by mosquitoes from an infected dog to its next blood meal on another dog, cat or ferret. That's how they spread and infect a new host animal. Nasty! Over the next 6 months adult heartworms grow to a length of one foot and live primarily in the pulmonary artery which carries blood from the heart to the lungs. With every beat of the heart blood gushes by these worms and knocks them against inside lining of the artery. Thump, thump, thump, thump all day long and with time arterial wall inflammation occurs and emboli (small blood clots) are sent out into the lungs causing severe inflammation. Infected animals start to cough and have limited exercise tolerance as a result of this lung damage. For dogs this usually takes a heavy worm burden and several years until it gets to this debilitating state, but in ferrets or cats just 1-3 worms can have devastating affects.

So what about heartworm disease in cats and why hasn't preventative been routinely prescribed for this species? Due to the decreased incidence of heartworm disease and lack of good diagnostic tests for its detection in this species the rationale for heartworm prevention has been somewhat less compelling than it is for dogs. As well, many cats never leave their owner's home and thereby are less likely to come in contact with heartworm carrying mosquitoes. However, we all know that mosquitoes make their way into our homes and over one-fourth of the cats diagnosed with heartworm disease at North Carolina State University 's College of Veterinary Medicine in Raleigh were solely indoor cats. Due to this fact and the added benefit of additional parasite control provided by the recommended preventatives, the doctors at Pet Care feel it is time to get cats on monthly parasite control as well.

Another advantage to year-round monthly heartworm preventative is that these products also prevent infection with the most common intestinal worms of dogs and cats. These include hookworms and roundworms in both species and whipworms in dogs. This is not only important for our companion pet's health but also due to the fact that roundworms and hookworms are zoonotic, meaning they can infect people as well. Accidental ingestion of roundworm eggs is most common in children who do not take the proper hygienic precautions after playing with a pet or playing in an area of the yard where the pet soils. Once ingested by a human, roundworm eggs hatch to larvae or baby worms and these migrate through the body looking for a place to settle down and live. However, as a result of being in the wrong host they become confused and continue to crawl around the body and have been known to damage the liver, eyes and brain among other organs. Hookworms are not quite as noxious as people are infected by coming in skin contact with the hookworm larvae that then proceed to tunnel under the skin causing an ugly, itchy rash.

What about fleas? Yes, they are vile blood sucking insects that are responsible for skin allergies in both dogs and cats and when they populate a house start to bite us as well. Remember, half the population of Middle Age's Europe was wiped out by the bubonic plague carrying rat flea! Since fleas really carry no redeeming qualities and no one likes them, the doctors recommend heartworm preventatives that can also effectively control flea populations. Another bonus is that all of these products are extremely safe and non-toxic to your pet. For dogs, our number one choice is Sentinel® from Novartis Animal Health as it prevents heartworms, the intestinal worms discussed above and contains a flea birth control agent known as lufeneron. [ note: Interceptor®, also from Novartis, is the same heartworm preventative just without the lufeneron] Lufeneron is a chitin inhibitor. Chiton is the exoskeleton of the insect and is what goes crunch when you crush it. Larvae develop within the flea egg and these larvae have a small pointed beak made of chiton which allows them to open the egg and thereby hatch. Without chiton this beak cannot form and flea eggs cannot hatch. Consequently the female flea cannot infest your home with the hundreds of fertile flea eggs she is capable of laying and a flea infestation never gets started. For cats we recommend Revolution® from Pfizer Animal Health which is a topical spot-on liquid applied monthly to the skin on the back of the cat's neck. This product will protect your cat year-round from heartworms, intestinal worms, and also kills 90% or more of the fleas that may hop on your cat. Pretty cool, huh?

For all of the above reasons the Companion Animal Parasite Council (CAPC), an independent council of leaders in parasitology, epidemiology, and veterinary and human medicine, recommends year-round heartworm prevention in areas of the country where heartworms are prevalent. This includes all of SE Virginia . Keeping your pet healthy and happy is our primary goal here at Pet Care Veterinary Hospital . By following these recommendations on parasite prevention you can help us accomplish this goal and at the same time diminish any potential human exposure. For more information on animal parasites and their control see www.capcvet.org.

Peter G. Fisher, D.V.M.