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Heartworm Testing: Why Your Dog Needs an Annual Check

0 Comments Posted by WestarborAdmin in Fleas Ticks & Heartworm, For The Dogs, Pet Health & Wellness on Thursday, April 15th, 2021.

Heartworm disease in dogs is one of those things you know happens, but you believe it can’t happen to your pet. It’s a common disease (veterinarians diagnosed over 200,000 positive cases of canine heartworm disease last year). Yet many dogs go without important heartworm testing and monthly preventatives that can keep them safe. This is unfortunate because heartworm disease is avoidable with the right precautions.

Spring is a great time to take an in-depth look at this parasitic disease and the importance of heartworm testing for your four-legged family member. Your friends at Westarbor Animal Hospital want you to have the right information, so let’s take a closer look!

Heartworm Disease in Dogs

The bite of a mosquito is the only way in which a pet becomes infected with heartworm disease. When an infected mosquito bites a pet, they transfer tiny heartworms called microfilariae into the bloodstream. From there, the microfilariae travel to the heart and develop into adult heartworms. These heartworms look like spaghetti and can grow to 12-14 inches or more in length.

Adult heartworms take about 6 months to develop fully. During this time, they take up residence in the blood vessels of the heart and lungs. There can be hundreds of heartworms damaging the heart, lungs and arteries. Over time, their presence disrupts the heart’s ability to pump blood, which results in heartworm disease.

All unvaccinated cats, dogs, and ferrets are susceptible to this disease. Dogs can live up to 5-7 years with this untreated condition, but cats generally show no signs of it until they have heart failure. 

Signs of heart disease in dogs include:

  • Coughing 
  • Lethargy
  • Loss of appetite
  • Difficulty breathing
  • Vomiting

If your canine friend experiences any of these symptoms, please contact us for a thorough examination.

The Benefits of Heartworm Testing

You will need a test to know whether your dog is already infected with heartworms since you won’t see symptoms in the earliest stages. There are two specific tests that detect heartworm in pets and both require just a small blood sample to test for heartworm proteins. 

The first test (the Heartworm Antigen Test) detects adult female heartworms, those that have already matured and are in the heart and/or lungs. The second form of testing looks for microfilariae in the bloodstream. There can be microfilariae in the bloodstream months before adult heartworms develop. When there is a positive or a weak positive result in the antigen test, your veterinarian will conduct a test for microfilariae. 

The most accurate tests for microfilariae are concentration tests. Through the use of a centrifuge, your veterinarian concentrates the blood sample to better detect microfilariae. 

Other forms of diagnostic testing include complete blood count and tests to look at the health of the kidneys and liver, EKG, X-ray of the chest, and ultrasound of the heart. These can help to determine the extent of the disease once diagnosed. 

Adult pets should have heartworm testing every year. It is the best way to detect heartworm infection before it develops into a more serious stage of the disease. Early detection through the use of these accurate and cost-effective tests prevents your pet from dealing with a serious condition down the road, including one that is fatal. 

You may ask why your pet needs testing if you have had them on a heartworm preventative. The question is a valid one and there are three main reasons:

  1. Missed dose — whether you miss a dose, go longer than you should between doses, or your dog spits out a heartworm pill without you knowing, it leaves a gap and opens the possibility of heartworm infection. Even one skipped month of your pet’s heartworm medication can result in a positive test later. 
  2. There’s still a chance of infection — It only takes one bite from an infected mosquito. While heartworm preventatives are great protection from heartworm infection, they are not 100% effective. This is why heartworm testing is an essential part of your pet’s annual examination. 
  3. Prevention after infection puts your dog at risk — Heartworm prevention given after infection can bring about serious harm. Heartworm preventatives given to a dog in the early stages of infection can trigger a serious, shock reaction as the microfilariae die. If adult heartworms are already present, preventatives won’t kill them, so they will continue to infect your dog until you start your pet on a treatment plan. 

If you would like to schedule an appointment for your pet’s annual heartworm testing and prescription renewal, or would like to ask questions, please feel free to call us.  Or learn more about heartworm disease from the American Heartworm Society.

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