Heartworm disease poses a deadly threat to dogs and cats, but doesn’t need to endanger your pet—heartworm prevention is easier, safer, and more effective than ever, and annual screening tests can identify early or hidden disease. So why does this devastating parasitic infection affect more than one million pets every year? Perhaps a lack of general awareness about heartworm disease and its real-and-present threat to pet health is to blame.

Cherry Knolls Veterinary Clinic wants to explain heartworm disease, and its harsh realities but simple prevention methods, so pet owners can easily protect their furry friends. Take this information “to heart,” and take action to protect your pet from heartworm disease. 

#1: Heartworm disease is a deadly but preventable threat to dogs and cats

Heartworm disease is transmitted through an infective mosquito’s bite. As the heartworm larvae enter circulation, they migrate to the heart and large lung vessels, where they can grow up to 12 inches. As the worms reproduce and compete for space, they irritate the vessel lining and restrict blood flow, leading to cardiovascular complications, respiratory difficulties, and death in untreated pets.

Heartworm prevention—available as a monthly oral or topical for dogs and cats or a 6- or 12-month injection for dogs—effectively kills any circulating immature heartworms (i.e., microfilariae), preventing them from reaching maturity, wreaking havoc, and reproducing.

#2: One bite to your pet can transmit heartworm disease

Part of the scientific genius—and veterinary frustration—behind heartworm disease transmission is its simplicity. Only one infective-mosquito bite is needed to transmit Dirofilaria immitis (i.e., heartworms). And, chances are, you won’t notice the bite. Unlike ticks that attach and feed for hours, mosquitoes bite, feed, and leave with barely a red mark left behind—usually hidden beneath your pet’s fur.

#3: Heartworm disease is treatable only in dogs

Waiting to see if your pet gets sick with heartworm disease is not a logical prevention strategy. Although treatment is available for dogs, the process is lengthy, painful, expensive, and dangerous.

Unfortunately, at this time, no safe treatment exists for cats suffering from heartworm disease, making consistent monthly prevention the only way to keep your cat safe.

#4: Heartworm prevention must be given to pets year-round

While mosquitoes are rarely seen during bitterly cold Colorado winters, these pesky bugs can reappear on mild weather days, or make a winter home in your basement, garage, or attic. Choosing to pause your pet’s preventives during the winter can leave your pet vulnerable to infection, and makes remembering to resume dosing when spring arrives less likely. 

#5: When your pet misses a dose, immature heartworms can reach adulthood

If your pet becomes infected during a heartworm preventive hiatus, the microfilariae have time to mature into adult worms—making them impossible to treat without full veterinary intervention.

#6: Pets with early heartworm disease rarely show signs

As microfilariae move through your pet’s tissues during the first two months following a bite, they are relatively harmless. But, when they reach the large lung vessels and heart, they mature and cause irritation and damage to the lining of these structures.

 At this point—roughly four to five months after the initial mosquito bite—this irritation may be  visible as clinical signs, including:

  • Persistent cough
  • Exercise intolerance
  • Fatigue after basic activity
  • Appetite changes
  • Occasional vomiting
  • Weight loss

As the disease progresses, pets may experience more dramatic signs, as the adult worms cause heart failure, respiratory distress, or blockages in major vessels.

  • Pot-bellied appearance from abdominal fluid build-up
  • Collapse
  • Coordination loss
  • Sudden death

#7: Annual heartworm screening tests identify early infection in pets

While consistent prevention is your pet’s best bet against heartworm disease, we also recommend annual heartworm testing at Cherry Knolls Veterinary Clinic. This simple blood test allows us to confirm that your pet’s preventive is effective, and helps you avoid the heartache of hidden illness, because break-through infections can occur. Heartworm testing is especially important if you have missed or forgotten your pet’s monthly preventive at any point.

#8: Cats get heartworm disease, but it’s different

Unlike dogs, cats are not natural hosts for Dirofilaria immitis, and their heartworm infection can present with unusual signs, or show no visible signs. Since heartworms cannot reproduce in cats, they tend to have small adult infections of only one or two worms. However, because of their small anatomy, one to two worms can still cause life-threatening damage.

Feline signs may mimic asthma or other respiratory diseases. Unfortunately, the first and only sign for many cats is sudden death.

#9: Natural methods are ineffective against heartworm disease in pets

Although natural strategies for preventing heartworm disease sound appealing, they can only work by repelling mosquitoes and discouraging the bite. Only FDA-approved veterinary heartworm disease preventives can eliminate circulating microfilariae from your pet’s system.

#10: Environmental control can help prevent heartworm disease—with veterinary preventives

Deterring mosquitoes with environmental control can be a great benefit to pet and human health. However, with heartworm disease, environmental management must be used as a complement—never a replacement—to preventives.

Some effective ways to reduce mosquito exposure include:

  • Removing standing water
  • Avoiding outdoor exercise during peak mosquito activity (e.g., dawn and dusk)
  • Using pet-safe mosquito repellent sprays or bandanas
  • Planting pet-safe, mosquito-deterring plants (e.g., lemongrass, marigolds, mint)
  • Skipping the citronella—these products are toxic to pets

Don’t start the spring season without a strong defense against heartworm disease. If your pet isn’t protected, contact Cherry Knolls Veterinary Clinic to schedule an exam and heartworm test.