Every dog and cat owner knows that heartworm prevention is essential for their pet's healthcare routine, but how much do you understand about heartworm disease?
What Is Heartworm Disease?
Heartworm disease, a severe and potentially deadly condition, is a stark reality for cats and dogs. It is caused by a parasitic roundworm called Dirofilaria immitis, transmitted through mosquito bites. The severity of this disease cannot be overstated, as it can lead to significant, long-lasting damage and even death if left untreated.
As the larvae mature, they reside in the lungs' heart and blood vessels, wreaking havoc and causing significant, long-lasting damage. These adult heartworms can reach a staggering 14 inches (36 cm), and a single dog can play host to a horrifying 250 worms. This invasion can lead to blood clots, inflammation of the lung tissue, severe allergic reactions, and all of which can be life-threatening for our furry friends.
Heartworm Basics
- Mosquito bites can transmit heartworms with just one bite.
- Heartworm disease impacts both dogs and cats.
- Both indoor and outdoor pets are vulnerable to heartworms.
- While heartworm disease is difficult to treat, it is easy to prevent.
- Early signs of heartworm are often hard to notice.
- Heartworms affect both the lungs and the heart.
How Heartworm Disease Can Be Transmitted?
The heartworm parasite (Dirofilaria immitis) is a stealthy enemy mosquitoes transmit. When a mosquito bites an infected animal, it inadvertently ingests microscopic heartworm larvae called microfilariae. These microfilariae then develop into infective larvae inside the mosquito's digestive system. The next time the mosquito bites another animal, it transfers these infective microfilariae through the bite wound, potentially causing heartworm disease. It's a chilling fact that a single mosquito bite can be enough to transmit heartworm disease in a dog or cat.
After transmission, the heartworm larvae develop under the skin before entering the bloodstream. They then travel to the lungs, where they mature into breeding adults.
Factors That Increase The Risk Of Heartworm Disease
Since mosquitoes transmit heartworms, pets in areas with mosquitoes are at risk. Mosquitoes thrive in warm climates, flooded regions, and near stagnant water. Even in colder climates, they can appear during brief warm periods, and small amounts of standing water, like bird baths or gutters, can become breeding grounds for mosquitoes.
Many pet owners believe indoor pets are safe from heartworms, but mosquitoes can quickly enter homes, putting indoor cats and dogs at risk.
The risk of heartworm transmission also increases with the number of infected hosts in the area, including other pets and wild animals such as ferrets, foxes, coyotes, raccoons, and wolves.
How Does Heartworm Prevention Work?
Heartworm preventatives do not treat existing heartworm disease or protect your pet from the initial infection.
These preventatives work by targeting heartworm larvae. They eliminate any microfilariae that have entered your pet's bloodstream in the past 30 days, stopping them from developing into adult worms. This interrupts the heartworm lifecycle, preventing the worms from breeding and migrating to the heart, lungs, and other organs.
Diagnosis Of Heartworm Disease
Your heartworm medication may recommend testing your pet for existing heartworms before use. These medications only prevent heartworm larvae from developing and cannot treat an existing infection.
Since symptoms of heartworm disease can take years to appear, a vet test is the only way to detect it early. Dogs may react adversely to the medication if they already have heartworm disease, even if they show no symptoms.
Testing your pet for heartworms is straightforward and affordable. Typically, a blood test can diagnose the disease, but your vet may also use additional tests, such as urine tests or X-rays.
Due to the heartworm lifecycle, these tests are only effective about six months after the initial infection.
Symptoms Of Heartworm Disease
Heartworm disease manifests differently in dogs and cats, so it's essential to recognize the specific symptoms in each.
Symptoms may not appear for several years after infection, by which time significant damage may have occurred. Regular blood tests are crucial for early detection, giving your pet the best chance to eliminate heartworms and recover fully.
The severity of symptoms depends on the worms' number, location (lungs, heart, kidneys), and your pet's activity level.
Heartworm Symptoms in Cats:
- Coughing
- Difficulty breathing
- Gagging
- Vomiting
Heartworm Symptoms in Dogs:
- Coughing
- Lethargy
- Loss of appetite
- Difficulty breathing
- Fainting
Treatment Prognosis and Options For Heartworm Disease
Treatments can be expensive and potentially dangerous once a dog or cat develops heartworm disease. The goal is to eliminate the heartworm without harming the pet.
Heartworm Treatment for Cats
The medication used to kill adult heartworms in dogs is unsafe for cats and can cause lung failure or death. Therefore, preventive measures are crucial for cats.
Currently, the only option for treating heartworm in cats is to manage the symptoms until the heartworms die off naturally, which can take 2-3 years. Treatment may include corticosteroids to reduce inflammation, diuretics to remove fluid from the lungs, and oxygen therapy in severe cases.
In some regions, surgical extraction of heartworms in cats is being trialed. As these trials advance and become more common, this method may become more effective in eliminating heartworm in cats.
Heartworm Treatment for Dogs
Treatment for heartworms in dogs has improved, but it still carries risks. Your vet will administer several injections, often spaced a month apart. Your dog must be hospitalized for the injections and confined for several days or weeks. This confinement is essential because their fragments can block blood vessels as the adult worms die and break apart. Limiting your dog's movement reduces the risk of these blockages. Your vet may also prescribe anti-inflammatory medications.
The success of treatment depends on factors like the stage of heartworm development and your dog's overall health. Generally, with proper care, the dogs' prognosisdogs' prognosis is good.
