Vet Blog

The Truth about Heartworms

May 10, 2018

Heartworms are a variety of internal parasites that are spread through the bite of infected mosquitos.

When the mosquito bites your dog, cat or ferret, it deposits immature heartworm (heartworm larvae) into the wound. These are microscopic, so it is impossible to tell at this stage if your pet has been infected. Once the larvae are inside your pet, they migrate to the blood vessels of the lungs and heart, which they then make their home. Over time they mature into adults, growing to between 8 and 12 inches in length. Once they reach maturity, they can reproduce over and over, causing a huge infestation of these parasites.

The effect of heartworms

An infestation of heartworms can have a devastating, and potentially fatal, effect on your pet. As heartworms increase in number, they begin to block the blood vessels in and around the heart and lungs. This prevents the flow of oxygenated blood around the body, causing damage to the major organs. Left untreated, an animal with heartworms will almost certainly die.

The difficulty with diagnosis

One of the most challenging aspects of treating a heartworm infection is identifying it. This is because symptoms often don't become apparent until there are a significant number of heartworms living inside your pet, and damage to the body has already started to occur.

When symptoms do become evident, they are easily overlooked or attributed to a simple cough or virus. Nevertheless, indicators to watch for include:

  • A soft, dry cough
  • Lethargy
  • Rapid breathing
  • Difficulty breathing
  • Loss of appetite
  • Weight loss

In some, rare cases, the worms may penetrate the brain and cause confusion, disorientation and seizures.

Can heartworms be treated?

Fortunately, there is a treatment that has been shown to be effective in killing adult heartworms. However, because they must be eradicated at every stage of their lifecycle to rid your pet entirely of the infestation, preventative medication to destroy the larvae must also be given.

It is also important to mention that the process of treating heartworms is lengthy and expensive. It requires a course of injections into their back that have a range of side effects. Your pet will need to stay overnight with our vet after each injection, so that he can be monitored for any problems. The entire course of treatment takes an average of 60 days.

Does my pet really need year-round preventative treatment or is this just a ruse by the manufacturers to make us buy more medication?

One of the biggest controversies surrounding preventative medication is the need to administer it throughout the year. After all, if a specific disease, such as heartworm, can only be transmitted via a mosquito, surely you only need to protect your furbaby during the summer months when mosquitos are prevalent?

Fact is, studies have shown that mosquitoes are becoming much more resilient to cold temperatures and can live throughout the winter months, particularly in the colder states. An open window or air vent is enough to allow a mosquito access to the interior of your home, and since just one bite is enough to cause a life-threatening heartworm infection and debilitating effects to your pet's health, most experts agree that not vaccinating your pet against this parasite is simply not worth the risk.

The importance of continual protection

The best way to protect your pet from the risks posed by a heartworm infection is to ensure that he receives preventative treatment all year round. There are several different preventatives available, and our Columbus NC veterinarian will be happy to advise which is the most suitable for your pet. Our vet may also be able to incorporate your pet's heartworm preventative into his regular schedule of preventive medication.

It is essential that you stick to the recommended schedule as closely as possible. Preventive medications are designed to only protect your dog for a specific number of weeks or months at a time, and so by missing a dose or administering one late, you could be leaving your furbaby vulnerable.

For further advice about heartworms and heartworm preventative medicine, please do not hesitate to contact our knowledgeable and experienced veterinary team at Bonnie Brae Veterinary Hospital in Columbus NC.