Heartworm is a very serious—and sometimes fatal—parasitic disease. All it takes is one mosquito bite to change a dog’s life forever. Fortunately, there are medications available that will protect your puppy so they can grow up into a healthy adult dog. Your local vets at East Valley Animal Hospital can prescribe the medicine your puppy needs for heartworm prevention. 

How Does Heartworm in Puppies Start?

Heartworm disease is only transmitted by mosquitoes. When they drink the blood of an infected wild animal, like a coyote, they can transfer heartworm larvae to the next animal they bite. Heartworms cannot be passed from one dog to another, or transferred through feces. However, because mosquitos are so prevalent, heartworm disease can still spread quite easily among animals.

Heartworms live up to seven years and grow to be a foot long. They infect the heart, lungs, and arteries and can cause lasting damage, as well as lung disease and heart failure. Heartworms will reproduce and multiply inside a dog’s body, so it’s very important to protect your puppy early in life. 

How to Prevent Heartworm in Puppies

Heartworm prevention is easy—all you need is a prescription from your vet. Preventive heartworm medication kills heartworm larvae before they can grow into worms. It can be administered as a chewable pill, a topical liquid, or an injection. You will want to start giving your puppy heartworm medication when they’re about 8 weeks old. Depending on the type of medication you choose, you’ll need to give them a new dose either once a month or once every six months. 

How Can I Tell If My Puppy Has Heartworms?

Because heartworms live so long, and take almost two months to mature, it’s unusual to notice any signs of heartworm in puppies until they are older and the disease is more advanced. It takes about 51 days for the larvae to grow up into worms and start causing problems. It can also take about six months before an infected dog will test positive for heartworm.

However, it’s still good to know what to watch for. The main symptoms of heartworm in dogs include:

  • Coughing and wheezing
  • Trouble breathing
  • Distended belly
  • Fatigue/reluctance to exercise
  • Loss of appetite
  • Weight loss

Preventive heartworm medication will not work if a dog already has mature heartworms inside its body—it only kills the larvae. That’s why it’s important never to miss a dose of heartworm prevention medicine and to get your dog tested regularly. The American Heartworm Society recommends testing puppies for heartworm when they are seven months old, and then again 6 months later, to make sure they are not infected. Adult dogs should get tested once a year.

Does Your Puppy Need a Prescription for Heartworm Prevention?

Every puppy deserves a good chance at a long, healthy life. Besides vaccinations, puppies also need medicine for heartworm prevention. If you have a new puppy, bring them to East Valley Animal Hospital in Gilbert for a wellness exam. We’ll discuss the types of vaccinations they’ll need, and help you decide which type of anti-heartworm medication will work best for your pup. Call us at 480-892-1577 or make an appointment online today. 


Photo by Ben Michel on Unsplash used with permission under the Creative Commons license for commercial use 06/06/2022.