Heartworm Disease 2011
Westside Family Pet Clinic recommends year round, monthly heartworm medication (such as Heartgard) to prevent heartworm disease in dogs & cats.
Positive Heartworm Case Fall 2010.
Here is the story (we will call the dog Harry):
Harry’s owner seemed to have done everything RIGHT! He adopted Harry last October and began giving heartworm preventative monthly year-round. Harry had tested negative for heartworm disease one week prior to his adoption. Harry received all of his necessary examinations and vaccinations, and seemed to be a healthy 1 year old dog. He was a few pounds underweight when adopted, but his new owner slowly got the necessary weight back on him.
At Harry’s annual exam last month a small amount of blood was collected for his heartworm/tick panel and he was heartworm positive! Additionally, microfilaria (heartworm larvae) were seen swimming in his blood sample under the microscope.
How did this happen?
Adult heartworms are undetectable with a test until they are 6 months old at the earliest, and oftentimes not until 7-9 months. Additionally, the test requires the presence of at least one female, so if an animal is only infected with males we may never know that they are present. In Harry’s case, he was likely infected prior to adoption but the worms were too young to detect.
Harry’s new owner was giving monthly preventative, which would not have killed the worms that were already too mature, but would have killed any new young larvae that were present.
Why then, did we see baby larvae in his blood?
Unfortunately, by putting a little weight on Harry, his owner inadvertently sent him into the next higher dosing range for heartworm preventative, and the babies that the adult female worms were laying, were not being effectively killed each month.
In this instance, we were able to catch the disease before Harry developed any of the devastating complications of heartworm disease. He will be treated to kill the adults, and will begin receiving the next dose up of Heartgard to prevent infection in the future.
This serves to remind all of us that heartworm disease is most definitely present and that we must remain vigilant in order to protect our pets. (Cats too! – a local practitioner just diagnoses 3 cases less than 2 miles from our clinic.)
Please contact us at Westside Family Pet Clinic if you have any questions!
Visit the American Heartworm Society’s website for additional information www.heartwormsociety.org.
Dr. Sarah Kalstrup
General Heartworm Biology/Prevention
The American Heartworm Society (www.heartwormsociety.org) states that although heartworm transmission decreases in the winter months, the micro-environments present in urban areas virtually ensures that the risk of transmission never reaches zero.
Heartworm transmission: A mosquito takes in microscopic heartworm larvae from an infected animal. The larvae mature (10-14 days) and then are passed to a dog or cat when they are subsequently bitten by this infected mosquito.
The larvae migrate into the tissues of the pet all the while growing larger, and eventually push themselves into the pets veins to begin circulating in the bloodstream (60-120 days).
Important note ****Heartworm preventatives such as Heartgard work backwards to kill any larvae that were transmitted in the previous month. If given monthly, and in the right dose, these medications have been found to be 100% effective****
Adult worms can eventually grow to be 10-15 inches long and are able to be detected by a blood test 6-9 months after the initial mosquito bite. If they reach this stage, they can begin to do irreparable damage to the heart and lungs, potentially resulting in premature death.
Once mature heart worms are present, treatment involves a series of three injections of poison deep into the back muscles of your dog. As the worms die and break apart, there is an increased risk of damage to the lungs and/or death while your pet’s system tries to absorb the pieces.
Westside Family Pet Clinic recommends year-round, monthly heartworm medication (such as Heartgard) to prevent the devastating consequences of heartworm disease.
Spring Heartworm Alert 2010
With our Wisconsin spring underway, mosquitoes are here! They’re a nuisance to you, but to your pets they are a deadly enemy. In a single bite, mosquitoes can transmit a microscopic heartworm to your dog or cat that within 6 months can have serious medical consequences.
Heartworms are blood parasites that make their home in your pet’s heart and pulmonary arteries (in the lungs). Infection occurs when a mosquito picks up a microscopic heartworm by biting an infected animal and then biting your pet, depositing the worm in the process.
The heartworm larvae then work its way to the heart & large vessels. They can grow to be up to 14 inches in length, and resemble strands of angel hair pasta. As the worms reach maturity and reproduce in your pet’s arteries, they can cause serious illness including heart failure, difficulty breathing, and even death.
Treating a heartworm infection can be risky (arsenic is only approved/effective treatment) and costly, and like any disease, taking preventive steps is a far better alternative.
YEAR-ROUND PREVENTATIVE MEDICATIONS AND YEARLY BLOOD TESTING ARE YOUR PET’S BEST DEFENSE.