Heartworm Awareness Month: Everything You Never Wanted To Know About Heartworms

April is Heartworm Awareness Month! These dangerous and disgusting worms are something every dog owner should be aware of. Read on as a local London, ON veterinarian goes over some basic information about heartworms. 


Do Dogs Need Heartworm Prevention Every Month?

Fido defintely needs to be kept current on his heartworm prevention. The schedule depends on the product used. If he’s on a monthly schedule, then yes, he would need it every month. There are now preventative products that may last 6 or even 12 months.

That said, those in northern climates, such as here in Canada, may choose to pause the medication during winter. While this is ultimately up to the owner, we would still recommend keeping up with it. Ask your vet for specific advice.

What Time Of Year Do Dogs Get Heartworms?

In most areas, summer is the most dangerous time, since that’s when mosquitoes are most common. However, Fido could contract them at any time. In southern areas, the risk is year-round.

The risk is lower in the north during the winter months, but is still there. Some mosquitos stubbornly hang on in the cold for longer than one would expect. (It’s also worth noting that rising average temperatures may increase the risk of infection in winter.)

Where Is Heartworm Most Prevalent?

Heartworms are a risk anywhere there are mosquitos. Cases have been reported throughout North America. Unfortunately, that means Fido can get infected anywhere in the US or Canada. 

Are Certain Breeds More Susceptible To Heartworm Than Others? 

Any dog can get heartworms, and at any point in their life. 

That said, pups with thin fur may have a somewhat higher risk, simply because it’s a little easier for mosquitoes to bite them. However, that doesn’t mean longhaired dogs are safe:  fluffy dogs are still vulnerable. 

What Do The Numbers Say About Heartworms?

The data doesn’t paint a pretty picture, unfortunately. 

Here are some of the numbers:

  • More than 70 types of mosquitoes can transmit heartworms.
  • Female heartworms get to be about 10 inches. males grow to about 12. 
  • They resemble spaghetti. (Ew) 
  • The larvae can live for a month inside the mosquito
  • Once a dog is infested, it only takes about 6 to 7 months for the worms to reach their adult size and start multiplying.

How Do Dogs Contract Heartworms?

Fido can’t get heartworms directly from another dog. In fact, the heartworm has enlisted everyone’s favorite insect—the mosquito—to spread them. That means Fido can get infected anywhere: even when he is safe and sound in his own doggy bed.

Basically, the mosquito will pick up heartworm larvae, which are technically known as microfilariae, by biting an infected dog. Then, when the mosquito bites another

pup, the heartworms will be injected into his bloodstream. From there, they grow and, before long, begin to multiply.

Can Heartworms Be Treated?

There is both good and bad news here. The good news is that there are treatment options available. The bad news? These options can be quite expensive, and can be pretty rough on poor Fido. Your pet may need to have his activities strictly curbed as he is being treated, to make sure his heart doesn’t get overstressed. That means only short walks, and no vigorous play. That isn’t much fun for the pup! With more severe cases, pets sometimes need to be kenneled.

A really bad infestation may require surgery. Needless to say, that can be quite expensive. Your canine buddy will also need to be monitored very closely during this time. 

What Are The Signs Of Heartworm Infestations In Dogs?

The symptoms can vary a bit from pup to pup. You may also not notice anything until the worms have matured, which can take about six months. A dry, mild cough is often the first red flag. You may also notice that Fido just doesn’t have much energy.

Here are some of the things to look for:

  • Lethargy
  • Weight Loss
  • Discolored Gums
  • Nosebleeds
  • Swollen Abdomen
  • Persistent Coughing
  • Loss Of Appetite
  • Breathing Issues
  • Fatigue
  • Lack Of Interest In Play
  • Exercise Intolerance

If the infestation persists, more serious symptoms will develop over time. These may include fainting, staggering, and heart attacks. Unfortunately, sudden death may also occur.

Can Cats Get Heartworms? 

Yes. Infestations are fairly rare in cats, simply because feline bodies aren’t as hospitable to the worms as canine ones are. However, don’t assume that Fluffy is safe. Even a single worm can cause permanent organ damage in a kitty. What’s even more concerning: cats sometimes show no signs, but may simply succumb to sudden death. Keep up on your feline pal’s preventative care as well. 


Do Other Animals Get Heartworms? 

Any and all canids can get heartworms. That includes not just Man’s Best Friend, but also his cousins, the wolf, coyote, and fox. Cats and ferrets are also susceptible. In fact, heartworms have even been found in sea lions!

Can People Get Heartworms?

Yes, humans can contract heartworm. Fortunately, though, this is quite rare. 


How Can I Keep My Dog From Getting Heartworms? 


The most important thing would be to keep up with Fido’s preventative care. Aside from that, you can also just take some measures to keep mosquitos away. You can use sonic repellers, for instance. Making your property friendly to pollinators and bats can also help. A single bat can eat 600 mosquitoes in just one night! Standing water tends to form mosquito nurseries, so dump out things like buckets and plant pots after it rains. 


What Happens If I Forget To Give My Dog His Preventative Care?


You’ll need to get your canine pal tested again before starting back up. This is because the products that protect Fido from infestations do not kill live worms. If your pet is already infested, preventative care won’t protect him from the worms that are already in his body. Ask your London, ON vet for more information. 


How Often Should My Dog Be Tested For Heartworm?


For most dogs, annual tests will be fine. However, some pooches may need more frequent tests. Keep in mind that some dogs will be at higher risk than others. Spending time around other dogs would of course increase your pet’s chances. Fido doesn’t even have to have direct contact: a neighbor’s dog three houses down could transmit the worms to him via mosquito.


Are Heartworms Getting More Prevalent?


Unfortunately, yes. As often happens with any type of medication or parasitic prevention, some worms seem to be becoming resistant. Also, it’s become more common for dogs to be adopted and transported from one part of the country to another, which has also contributed to rising numbers. For example, many people adopted dogs from the South after Hurricane Katrina. Louisiana, as mentioned, is a heartworm hotspot, due to its warm, wet climate. Therefore, it’s not surprising that cases increased in the north. 


That said, there is no need to panic. Just be sure to keep up with your canine pal’s preventative care and watch for symptoms. Contact your London, ON veterinary clinic if you notice anything off. 


Make An Appointment With Your London, ON Veterinary Hospital


Do you need to get your dog caught up on his heartworm medication? Is Fido overdue for an appointment? Contact us, your local London, ON pet clinic, anytime. 

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