Heartworms in pets or Dirofilaria immitis is a severe and potentially fatal disease in pets. This serious disease is caused by foot-long worms that live in your pet’s heart, lungs and blood vessels, and in so many cases, it could lead to severe health issues or even death.

The most responsible creature for transmitting this infection are mosquitoes because when they bite an infected animal, they draw blood that contains microscopic baby worms, then when an infected mosquito bites another animal, they will pass the virus to your animal.

It takes about six months for the larvae to develop and attack the vital organs of your pet. Moreover, once the number of mosquitoes increases, there is also the possibility that pets will contract more heartworms.

So, if you want to prevent this disease and keep your pet safe, here are some heartworm myths debunked by animal experts. Read on for more info!

Heartworm disease can only be contracted by dogs

This myth is totally wrong and fake, of course! It seems that dogs are more susceptible to contracting this virus because they are one of the most popular pets and their owners notice this much faster than in the case of other animals – but this doesn’t mean that cats, ferrets, wolves, coyotes, foxes and sea lions won’t get the heartworm disease.

“Cats are more resistant than dogs as a heartworm host,” but they can still become infected, says Dr. Laura Hatton, a veterinarian with BluePearl Veterinary Partners in Overland Park, Kansas.

Just like dogs, felines can develop adult heartworms, but these worms will die before reaching their full maturity. According to animal experts, there is no treatment for this disease in cats yet, so try your best to protect your beloved furry friend as much as possible.

Outdoor pets are more likely to get the virus than indoor pets

The truth is that there are certain situations in which we can admit that indoor pets are more protected than those that live outdoors, but in this case, the risk of getting sick is the same, no matter where they live. In fact, there are a lot of infected mosquitos that can easily get inside your house and transmit the heartworm disease to your pet.

According to Dr. Hatton, a considerable proportion of heartworm disease infections are reported in indoor felines.

“Even if your pampered pooch only goes outside for bathroom breaks or brief walks, remember — it takes just one bite from an infected mosquito to infect a pet,” says Dr. Rehm.

Animals should be protected only during the summer

Even though many people believe that animals should be protected only during the summer season, it is clear that the “mosquito season” can fluctuate depending on the region, and other factors that can affect the whole year. Hence, you should protect your animals as long as possible and don’t hesitate to go to the vet when you notice something strange in the behavior of your pet.

“Generally, mosquito activity will begin when the temperature reaches the 50 degrees Fahrenheit level and typically tapers off as the temperatures cool,” Dr. Hatton says.

“It’s not unheard of for mosquitos to be active in 40-degree temperatures,” says Dr. Susan Jeffrey, a veterinarian with Truesdell Animal Hospital in Madison, Wisconsin.

Unfortunately, there are some species of mosquitos that can hibernate, so they can emerge during the winter. So, it’s quite impossible to predict when the last mosquito will appear and if it is infected or not.

“Mosquitos also seek out warm, protected places like crawl spaces and decks where they can survive until well after the last leaves have fallen. For these reasons, the AHS recommends year-round prevention for all pets,” says Dr. Rehm.

In dry climates, animals are less likely to develop the disease

This is another myth that pet owners should stop believing. According to animal experts, cases of animals infected with heartworm disease have been reported in all 50 American states.

“Mosquitos are highly adaptable and will find other places to breed, even during a drought. While some mosquitos breed and hatch during rainfall, others prefer tires, birdbaths or tin cans to reproduce,” said Dr. Hatton.

Another favorable environment for the reproduction of mosquitoes are ponds, lakes and swimming pools. So, even if you live in a dry climate or not, you can’t completely protect your pet from mosquito bites. But taking your pet to the vet as often as possible is your responsibility.

“The lower likelihood that pets are protected from heartworms in desert regions makes the presence of just one heartworm-positive dog or coyote in a neighborhood a serious concern,” said Dr. Rehm.

Animals won’t die from this type of disease

It is true that there are some cases of sick animals that can recover if they receive special treatment, but many creatures that are infected with this virus are not so lucky, because unfortunately, heartworm disease could be fatal for our furry friends.

“Heartworms lead to an inflammatory reaction that can cause permanent damage to the blood vessels in the lungs. Apart from the risk of fatality, heartworms can compromise an animal’s quality of life and cause debilitating clinical signs and symptoms, which may improve but not necessarily resolve, even with treatment,” said Dr. Hatton.

In dogs, the symptoms can be quite severe and obvious, but the disease begins with an insistent cough. “Fatigue, difficulty breathing and weight loss are common later in the disease,” Dr. Hatton says. “Left untreated, dogs can go into heart failure and ultimately die.”

In cats, symptoms may include coughing, vomiting and asthma. “The death of one adult heartworm in a cat can cause that cat to die abruptly.”

Pets don’t need the annual heartworm test if they are on preventatives

Even if your pet has been receiving preventive treatment for a year, this does not mean that you have to skip the annual heartworm test. According to animal experts, in many cases, heartworm preventives are really efficient, but you can’t be entirely sure of that.

Unfortunately, there are some cases of dogs that receive treatment to prevent this disease, but they still become infected. So, you should take into consideration that the heartworm test, if you want your dog to be healthy and safe. “I’ve had two cases of dogs with heartworm who were on monthly preventatives and didn’t miss doses,” says Dr. Jeffrey.

“The best of pet owners can be forgetful, and missing just one dose of a monthly medication—or giving it late — can leave a dog unprotected. And even if you do everything right and on time, it’s no guarantee. Some dogs spit out their heartworm pills when their owners aren’t looking. Others may vomit their pills or rub off a topical medication. Fortunately, heartworm tests are safe and can be conducted during your pet’s annual checkup,” advises Dr. Rehm.

This disease is contagious

Even though heartworm disease is often called a “virus”, due to the confusion created by the fact that the animals become infected (so there is practically an infection in their body), it doesn’t make this disease contagious, or at least not directly between mammals.

“Heartworm is spread through a mosquito [that bites and] acquires the heartworm larvae from other infected dogs, coyotes, wolves or foxes,” Dr. Hatton says. “The infected mosquito then bites a dog or cat and transmits the immature worms to them. If not on heartworm preventive, the larvae mature and multiply, causing damage to the heart and lungs.”

According to experts, there are very rare cases of humans contracting this disease. “Humans are considered [to be] dead-end hosts. It’s extremely rare for humans to get heartworm disease, but they can be exposed to heartworm disease through the bite of a mosquito and end up with lung pathology and granulomas in various organs,” Dr. Hatton says.