What Every Dog Owner Should Know About Heartworm Disease
What is Heartworm Disease?
Heartworm disease is a serious health problem in many parts of the world. It is
caused by the roundworm, Dirofilaria immitis, a parasite that lives in the heart
and major arteries of the lungs. Yet, it is an infection that can be prevented.
The Heartworm Life Cycle
Heartworms (Dirofilaria immitis) have been found in a variety of wild and domestic
mammals. Mosquitoes carry immature forms of heartworm from an infected animal to
a new host by taking a blood meal from both animals. As the mosquito feeds from
the first animal, usually a dog, it picks up microfilaria (the offspring of adult
heartworms) as it engorges with blood. These microfilaria mature in the mosquito,
developing into infective larvae of D. immitis. When the mosquito subsequently bites
another animal, the larvae are introduced to the new host through the bite wound.
The larvae eventually make their way to the heart and associated blood vessels by
migrating through the body. Inside the heart they mature to adults and begin producing
microfilaria, completing the lifecycle. These new microfilaria are then ready to
be passed on to another dog or cat through the same process.
Are all Dogs at Risk?
Dogs are the most commonly infected mammals and are considered the preferred host
of the heartworm. While the highest prevalence of heartworm infection is in areas
with heavy mosquito populations, heartworm-infected animals can be found in all
types of environments. The mobility of people and our four-legged companions as
well as the widespread prevalence of mosquitoes make heartworm disease a health
consideration no matter where you live. Ask your veterinarian for recommendations
regarding diagnosing and preventing this disease in your pet.
What Are The Signs of Heartworm Disease in Dogs?
The severity and onset of clinical signs relate to 3 things: the number of worms,
the duration of the infection and the dog’s response. Many dogs infected with heartworms
may not show any evidence of the infection in the early stages of the disease. Signs
can eventually appear and will worsen with increased numbers of worms and with lengthy
infections, making early detection and prevention programs an important part of
managing your pet’s health.
Initially dogs tend to develop a cough and experience difficulty breathing. They
may also exhibit a decreased tolerance to exercise, develop fainting episodes or
suffer severe weight loss. Since the heart and lungs are affected, many of the clinical
signs seen or observed are typical of heart failure, pneumonia or other debilitating
diseases. Many other less serious diseases can cause similar clinical signs, so
it is almost impossible to diagnose heartworm disease based on clinical signs alone.
A blood test is necessary to definitively diagnose heartworm infection.
How do I know if my Dog has Heartworm?
Because most dogs in the early stages have no outward signs of disease, your veterinarian
will want to run a simple test for heartworm infection. Testing for heartworm infections
is routinely done in areas where mosquitoes live and the prevalence of heartworm
infection is high. The test itself requires a blood sample from your dog, and can
quickly determine if your dog has heartworm or not. Blood antigen tests are highly
reliable and can be preformed in the clinic while you wait for the heartworm status
of your dog to be determined.
My Dog rarely goes outside; can it be infected with Heartworms?
Dogs that rarely go outside are at lower risk of becoming infected because of the
reduced exposure to mosquitoes. However, heartworm infections have been reported
in dogs that rarely go outside. Such infections may be caused by infected mosquitoes
that have gained access to the house. In addition, most dogs make frequent short
trips outside, during which mosquito bites are possible.
When do Veterinarians Recommend Testing for Heartworm Infection?
Veterinarians recommend testing for heartworm infection before beginning heartworm
preventive medication, at regular intervals after the dog is on a preventive and
when dogs have clinical signs consistent with heartworm disease. In heartworm endemic
areas, testing is generally recommended as part of the annual physical.
Can Heartworm Infection be prevented?
Fortunately, heartworm infection can be prevented if preventives are started early
and are consistently given throughout the dog’s life. There are a number if medications
available that prevent heartworm infection in dog’s. However, preventives will not
eliminate an existing infection. Knowing the heartworm infection status of your
dog is an important part of keeping your dog healthy and fit. We carry Heartguard
Plus a monthly chewable and Revolution.
What can be done of my Dag has Heartworm?
Medical intervention is necessary to achieve a favorable outcome for the dog infected
with heartworms. Your veterinarian will choose a course of action that will most
effectively deal with your dog’s disease and clinical signs. Medications to eliminate
adult heartworms and immature heartworms are available. Once successfully treated,
preventives and regular monitoring with a heartworm test should become part of your
dog’s healthy maintenance plan.
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