Heartworms: Dangerous Parasites

Animal lovers are special people. We have unique hearts comprised of something more than the traditional four chambers and anatomically correct assortment of blood vessels. We also have an intangible place in our hearts that serves no physical function but is reserved entirely for the pets we love. Our pets have special hearts, too. They love us in return in their own unique way.

But besides being the symbol of love, hearts are essential for life. So, for the love of our pets, let’s focus on the physical nature of their hearts and how we can keep these loving hearts (and the rest of their bodies) healthy. Let’s consider a specific health threat—heartworm disease.

THE HEARTWORM LIFE CYCLE

The heartworm is a filarid or “threadlike” worm that needs a carrier or “vector” to infect an animal. The heartworm’s carrier is the pesky mosquito. When a mosquito takes a blood meal from an infected dog, it can ingest tiny, immature forms of the heartworm called microfilariae. Microfilariae are the first stage of the heartworm life cycle. These tiny larvae enter the mosquito’s body and grow as they molt from one stage to the next. After a sufficient period of development, the immature heartworms are ready to move to a new residence. With its incubation role complete, the mosquito can carry the larvae to a new home—an unprotected dog or cat—and literally drop them off.

The mosquito deposits the larvae onto the surface of the pet’s skin. Some of the larvae die here, but many make their way into the animal’s body through the mosquito’s bite wound and begin a long journey toward their final destination near the heart. Migrating through the subcutaneous tissues of the pet, the larvae continue to mature. The larvae then penetrate a thin-walled blood vessel (a vein) that serves as an expressway toward the animal’s heart.

The heartworms eventually grow into mature adult heartworms. Contrary to their name, heartworms don’t actually reside in the heart, but rather set up residence in the pulmonary artery, a major blood vessel near the heart. Once in their new home, the heartworms begin to wreak havoc on their unsuspecting host—an unprotected dog or cat.

Dogs and cats react very differently to the presence of heartworms. Our easy-going, willing-to-do-anything-to-please dogs accept their heartworm guests, providing them with a comfortable place to live and raise a family. Male and female adult worms breed and have children (microfilariae) that venture away from their comfy lodging in the pulmonary artery, enter the general circulation, and hitch a ride with the next hungry mosquito, thereby completing their life cycle.

Cats, on the other hand, are not hospitable to heartworms. In fact, cats often eliminate their guests before they reach adulthood by activating their own unique immune systems. The feline immune response reduces the number of worms that reside in the pulmonary arteries. Even with fewer worms than their canine counterparts, however, cats with heartworm infection can become quite ill.

SIGNS OF INFECTION

How does a pet owner know when his dog or cat has heartworms? Does the pet look different? No, she often looks just fine. We can watch for physical signs, but the infection may be well under way before the dog or cat becomes ill. It is far better to have your veterinarian perform the appropriate tests to determine your pet’s heartworm status before the damage is done. If your pet is exhibiting any of the symptoms described below, take her to your veterinarian as soon as possible.

Heartworm-positive dogs may become lethargic or exercise intolerant or have difficulty breathing. Dogs can develop cardiac problems and retain fluid in their lungs and abdomen due to heart failure. Live adult worms usually hold on tightly to their home in the pulmonary artery, but when they die, the worms can be swept into the bloodstream and eventually lodge in tiny blood vessels in the lungs. These dead worms or worm fragments essentially behave like blood clots, called pulmonary emboli, and their presence in the blood vessels of the dog’s lungs can be fatal. Also, if there are many adult worms in the dog, they can band together and block even larger vessels, resulting in a condition called caval syndrome, which may require surgical removal of the worms.

Cats, unlike dogs, rarely have heart problems as a result of heartworms, but they can suffer severe, even deadly, lung problems. Infected cats may cough or have difficulty breathing. Cats may also be lethargic or, in rare instances, suffer neurologic problems. Other cats exhibit gastrointestinal signs such as vomiting. If your cat experiences vomiting unrelated to eating, heartworms may be the culprit.

Also unlike dogs, cats are severely affected not only by the presence of adult heartworms but by the presence of immature heartworms as well. Although cats eliminate many of the immature larvae before they reach adulthood, the mere presence of these larvae poses a significant health threat to cats. The respiratory syndrome associated with immature heartworms is called HARD, or heartworm-associated respiratory disease, and can be debilitating or fatal to your cat.

ROUTINE TESTING

Besides physical signs, how does a pet owner know if his pet has heartworms? Should we wait until she becomes ill? Absolutely not! Early diagnosis of heartworms means early intervention— and early intervention means our pets have a greater chance of surviving heartworm infection.

To prevent illnesses, we should have our dogs and cats examined on a regular basis. Dogs and cats should be tested for heartworms at least once a year. Because cats are more difficult to diagnose, they may additionally require radiographs or cardiac ultrasounds to determine their heartworm status.

HEARTWORM PREVENTION

The devastating effects of heartworm disease are something we pet lovers never want our dogs and cats to endure—and they don’t have to. Heartworm disease is preventable. There are a variety of oral and topical medications that interfere with the development of immature heartworm larvae into adult worms. The interference occurs early enough in the heartworm life cycle to prevent HARD in cats as well.

Many medications are available, so it should be easy for you to find the one that is best for both you and your pet. Oral and topical monthly medications work well. Discuss the available products with your veterinarian, and you’ll learn that most of them prevent more than heartworms. Many also prevent intestinal parasites, fleas, and even ear mites.

The prevention of intestinal parasites is important—not only for our pets, but for us, too. Some of these intestinal parasites are zoonotic, which means they can be transferred from animals to humans. So for the love of our pets and the love of our human family members, we should keep our dogs and cats on monthly heartworm medication.

The most important thing regarding heartworm prevention is not which preventive we choose, but how we administer it. Monthly heartworm medications need to be given monthly. That means no skipping or being late. If you have an unfailing memory, that’s great, but if you’re like the rest of us, you may need a little monthly prompting. Try putting a sticker on your calendar or circling the due date for the preventive. Or you could give the medication when you pay the rent or mortgage, or when you get your paycheck. If you live electronically, program the reminder into your device. Your veterinarian may even offer personal email reminders.

We live in a very busy world, but even so, there is no reason to miss something as important as heartworm prevention.

Yes, we are true pet lovers. And we want our pets around to love us in return for a very long time. So if your heart holds a special place for dogs and cats, remember to protect their hearts (and the rest of their bodies) from the devastating effects of heartworm disease.

Heartworm Disease Is Preventable

The bad news is that heartworm infection can be devastating to dogs and cats. The good news is that heartworm infection is preventable. Compared with the risk and cost associated with treating heartworm-infected dogs (and the fact that no approved treatment exists for cats), heartworm prevention is safe, easy, and inexpensive. By giving prescribed medications monthly, we can protect our pets so they do not have to suffer the consequences of heartworm infection. Ask your veterinarian which preventive is best for your pet.

Cats Need Protection, Too

Most people know that dogs are susceptible to heartworm infection, but they don’t realize that cats can become infected, too. In fact, feline heartworm infection can be debilitating or even fatal, and there is no approved treatment for adult heartworms in cats. For this reason, the American Heartworm Society and the Companion Animal Parasite Council advise pet owners to give their dogs and cats monthly heartworm medication year-round.

Car Travel Tips for Pets

For some pet parents, a trip’s no fun if the four-legged members of the family can’t come. But traveling can be highly stressful, both for you and your animal companions. With thoughtful preparation, you can ensure a safe and comfortable trip for everyone.
Planning a road trip? Traveling with a pet involves more than just loading the animal in the back seat and motoring off—especially if you will be driving long distances or plan to be away for a long time. The ASPCA offers the following tips to help you prepare for a safe and smooth car trip:

1. Keep your pets safe and secure in a well-ventilated crate or carrier. There are a variety of wire mesh, hard plastic and soft-sided carriers available. Whatever you choose, make sure it’s large enough for your pet to stand, sit, lie down and turn around in. And P.S., it’s smart to get your pet used to the carrier in the comfort of your home before your trip.
   
2. Get your pet geared up for a long trip by taking him on a series of short drives first, gradually lengthening time spent in the car. And please be sure to always secure the crate so it won’t slide or shift in the event of a quick stop.
   
3. Your pet’s travel-feeding schedule should start with a light meal three to four hours prior to departure. Don’t feed your furry friend in a moving vehicle—even if it is a long drive.
   
4. Never leave your animal alone in a parked vehicle. On a hot day, even with the windows open, a parked automobile can become a furnace in no time, and heatstroke can develop. In cold weather, a car can act as a refrigerator, holding in the cold and causing the animal to freeze to death.
   
5. What's in your pet’s traveling kit? In addition to travel papers, food, bowl, leash, a waste scoop, plastic bags, grooming supplies, medication and a pet first-aid kit, pack a favorite toy or pillow to give your pet a sense of familiarity.
   
6. Make sure your pet has a microchip for identification and wears a collar with a tag imprinted with your home address, as well as a temporary travel tag with your cell phone, destination phone number and any other relevant contact information. Canines should wear flat (never choke!) collars, please.
   
7. Don't allow your pet to ride with his head outside the window. This can subject him to inner ear damage and lung infections, and he could be injured by flying objects. And please keep him in the back seat in his crate or with a harness attached to a seat buckle.
   
8. Traveling across state lines? Bring along your pet’s rabies vaccination record, as some states requires this proof at certain interstate crossings. While this generally isn’t a problem, it’s always smart to be on the safe side.
   
9. When it comes to H2O, we say BYO. Opt for bottled water or tap water stored in plastic jugs. Drinking water from an area he’s not used to could result in tummy upset for your pet.
   
10. If you travel frequently with your pet, you may want to invest in rubberized floor liners and waterproof seat covers, available at auto product retailers.

For more pet tips, please visit: http://www.aspca.org/

Top 10 Pet Poisons of 2009

With various dangers lurking in corners and cabinets, the home can be a minefield of poisons for our pets. In 2009, the ASPCA’s Animal Poison Control Center (APCC) in Urbana, IL, handled more than 140,000 cases of pets exposed to toxic substances, many of which included everyday household products. Don’t leave it up to Fido or Fluffy to keep themselves safe. Below is a list of the top 10 pet poisons that affected our furry friends in 2009.

1. Human Medications
   For several years, human medications have been number one on the ASPCA’s list of common hazards, and 2009 was no exception. Last year, the ASPCA managed 45,816 calls involving prescription and over-the-counter drugs such as painkillers, cold medications, antidepressants and dietary supplements. Pets often snatch pill vials from counters and nightstands or gobble up medications accidentally dropped on the floor, so it’s essential to keep meds tucked away in hard-to-reach cabinets.
   
2. Insecticides
   In our effort to battle home invasions by unwelcome pests, we often unwittingly put our furry friends at risk. In 2009, our toxicologists fielded 29,020 calls related to insecticides. One of the most common incidents involved the misuse of flea and tick products—such as applying the wrong topical treatment to the wrong species. Thus, it’s always important to talk to your pet’s veterinarian before beginning any flea and tick control program.
   
3. People Food
   People food like grapes, raisins, avocado and products containing xylitol, like gum, can seriously disable our furry friends, and accounted for more than 17,453 cases in 2009. One of the worst offenders—chocolate—contains large amounts of methylxanthines, which, if ingested in significant amounts, can cause vomiting, diarrhea, panting, excessive thirst, urination, hyperactivity, and in severe cases, abnormal heart rhythm, tremors and seizures.
   
4. Plants
   Common houseplants were the subject of 7,858 calls to APCC in 2009. Varieties such as azalea, rhododendron, sago palm, lilies, kalanchoe and schefflera are often found in homes and can be harmful to pets. Lilies are especially toxic to cats, and can cause life-threatening kidney failure even in small amounts.
   
5. Veterinary Medications
   Even though veterinary medications are intended for pets, they’re often misapplied or improperly dispensed by well-meaning pet parents. In 2009, the ASPCA managed 7,680 cases involving animal-related preparations such as non-steroidal anti-inflammatory drugs, heartworm preventatives, de-wormers, antibiotics, vaccines and nutritional supplements.
6. Rodenticides
   Last year, the ASPCA received 6,639 calls about pets who had accidentally ingested rat and mouse poisons. Many baits used to attract rodents contain inactive ingredients that are attractive to pets as well. Depending on the type of rodenticide, ingestions can lead to potentially life-threatening problems for pets including bleeding, seizures or kidney damage.
   
7. Household Cleaners
   Everybody knows that household cleaning supplies can be toxic to adults and children, but few take precautions to protect their pets from common agents such as bleaches, detergents and disinfectants. Last year, the ASPCA received 4,143 calls related to household cleaners. These products, when inhaled by our furry friends, can cause serious gastrointestinal distress and irritation to the respiratory tract.
   
8. Heavy Metals
   It’s not too much loud music that constitutes our next pet poison offender. Instead, it’s heavy metals such as lead, zinc and mercury, which accounted for 3,304 cases of pet poisonings in 2009. Lead is especially pernicious, and pets are exposed to it through many sources, including consumer products, paint chips, linoleum, and lead dust produced when surfaces in older homes are scraped or sanded.
   
9. Garden Products
   It may keep your grass green, but certain types of fertilizer and garden products can cause problems for outdoor cats and dogs. Last year, the ASPCA fielded 2,329 calls related to fertilizer exposure, which can cause severe gastric upset and possibly gastrointestinal obstruction.
   
10. Chemical Hazards
    In 2009, the ASPCA handled approximately 2,175 cases of pet exposure to chemical hazards. A category on the rise, chemical hazards—found in ethylene glycol antifreeze, paint thinner, drain cleaners and pool/spa chemicals—form a substantial danger to pets. Substances in this group can cause gastrointestinal upset, depression, respiratory difficulties and chemical burns.
    Prevention is really key to avoiding accidental exposure, but if you suspect your pet has ingested something toxic, please contact your veterinarian or the Animal Poison Control Center’s 24-hour hotline at (888) 426-4435.

For more information about household poisonous plants please visit:
http://www.aspca.org/pet-care/poison-control/plants/