Heartworm Information

Learn more about heartworm and how you can protect your pets from this potentially fatal disease below.

Heartworm Testing and Prevention

At the Animal Hospital of Tiffin, we want to make sure our clients are thoroughly informed about this potentially deadly disease. Below are some common FAQs that might help answer any questions or concerns about heartworm disease. Please feel free to call us at 419-455-0470 for any other concerns you might have about your pet.

What is heartworm disease?

Heartworm disease is a serious and potentially fatal disease in pets in the United States and many other parts of the world. It is caused by foot-long worms (heartworms) that live in the heart, lungs, and associated blood vessels of affected pets, causing severe lung disease, heart failure, and damage to other organs in the body. Heartworm disease affects dogs, cats, and ferrets, but heartworms also live in other mammal species, including wolves, coyotes, foxes, sea lions, and—in rare instances—humans. Because wild species such as foxes and coyotes live in proximity to many urban areas, they are considered important carriers of the disease.

How is heartworm disease transmitted?

The mosquito plays an essential role in the heartworm life cycle. Adult female heartworms living in an infected dog, fox, coyote, or wolf produce microscopic baby worms called microfilaria that circulate in the bloodstream. When a mosquito bites and takes a blood meal from an infected animal, it picks up these baby worms, which develop and mature into “infective stage” larvae over a period of 10 to 14 days. Then, when the infected mosquito bites another dog, cat, or susceptible wild animal, the infective larvae are deposited onto the surface of the animal’s skin and enter the new host through the mosquito’s bite wound. Once inside a new host, it takes approximately 6 months for the larvae to mature into adult heartworms. Once mature, heartworms can live for 5 to 7 years in dogs and up to 2 or 3 years in cats. Because of the longevity of these worms, each mosquito season can lead to an increasing number of worms in an infected pet.

What are the signs of heartworm disease?

In the early stages of the disease, many dogs show few symptoms or no symptoms at all. The longer the infection persists, the more likely symptoms will develop. Active dogs, dogs heavily infected with heartworms, or those with other health problems often show pronounced clinical signs. Signs of heartworm disease may include a mild persistent cough, reluctance to exercise, fatigue after moderate activity, decreased appetite, and weight loss. As heartworm disease progresses, pets may develop heart failure and the appearance of a swollen belly due to excess fluid in the abdomen. Dogs with large numbers of heartworms can develop a sudden blockage of blood flow within the heart leading to a life-threatening form of cardiovascular collapse. This is called caval syndrome and is marked by a sudden onset of labored breathing, pale gums, and dark bloody or coffee-colored urine. Without prompt surgical removal of the heartworm blockage, few dogs survive.

Why do we recommend testing for heartworm disease?
Annual testing is necessary, even when dogs are on heartworm prevention year-round, to ensure that the prevention program is working. Heartworm medications are highly effective, but dogs can still become infected. If you miss just one dose of a monthly medication—or give it late—it can leave your dog unprotected. Even if you give the medication as recommended, your dog may spit out or vomit a heartworm pill—or rub off a topical medication. Heartworm preventives are highly effective, but not 100 percent effective. If you don’t get your dog test, you won’t know your dog needs treatment. Heartworm preventatives can cause adverse reactions in dogs with heartworm disease. This is why we require an up-to-date heartworm test in order to purchase prevention.
How do we test for heartworm disease?
Our heartworm test is called a 4Dx Snap test. This can be performed in the clinic with just a few drops of blood in less than 10 minutes. We also have the option of collecting the blood and sending it to our partner reference laboratory. The unique part about our heartworm test (and the reason we often refer to it as a blood parasite screen), is that it also tests for 3 different tick-borne diseases – Lyme disease, Anaplasmosis, and Ehrlichiosis.
Why do we recommend year-round heartworm prevention?

Because the life cycle of the heartworm is so long, it takes several months for a larva to become an adult heartworm. If your dog is infected late in the fall and is taken off of heartworm prevention over the winter, there is a high likelihood of developing the disease. Prevention can be purchased oftentimes for less than $10 per month whereas treating a case of heartworm disease can cost $1500-3000. Our heartworm prevention products also have intestinal parasite prevention in them as an added bonus.

What types of prevention are available?

We offer several types of stand-alone heartworm prevention products along with a product combined with flea prevention. We can talk to you about your preferences and your pet’s lifestyle to choose the best product for you. We often have rebates available on several of the products as well to help make it more cost-effective for you.

Heartgard Plus (ivermectin/pyrantel) – A beef-flavored chewable that is given monthly. Also treats and controls roundworms and hookworms

Interceptor Plus (milbemycin oxime/praziquantel) – A chicken-flavored chewable that is given monthly. Also treats and controls roundworms, hookworms, whipworms, and tapeworms.

Advantage Multi (imidacloprid/moxidectin) – A topical solution that is given monthly on the back of the neck. Also treats and controls roundworms, hookworms, and whipworms. This product also kills and prevents fleas and sarcoptic mange.

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