Wednesday, 07/13/2022

Canine heartworm disease is a severe tropical parasitic infection.The disease is caused by a parasitic worm known as Dirofilaria immitis. The worm lives in the small blood vessels of dogs and other mammals, including humans and many pets such as cats, pigs, foxes, and even horses. 

However, research has shown that canine heartworm disease prevalence is 28% more compared to felines. The same study has found that Dirofilaria repens microfilariae and Acanthocheilonema reconditum microfilariae are observed in dogs taken under the radar of study. Microfilariae from Dirofilaria immitis or Acanthocheilonema reconditum, also called Dipetalonema reconditum, are the vast, extracellular filarial larvae. These parasites have an elongated “wormlike” anatomical structure.

Dirofilaria immitis adult females live inside certain mosquitoes that feed on warm-blooded animals. Once they bite, these female worms mate in the dog’s blood cells to produce more offspring called microfilariae. The microfilariae move into the dog’s bloodstream and mature into adult male and female worms inside the dog’s heart. 

The ailment is treatable with medication and can be prevented by monthly heartworm preventative drugs. But before we explain how to prevent your dog from contracting this dangerous parasite, let’s take a closer look at heartworm diseases as a whole, about the causes, symptoms & preventions.

What is Heartworm Disease in Dogs?

Heartworms in dogs are a fatal disease that can affect the pet’s health, lungs, and blood vessels. It leads to heart failure, lung disease, or organ damage of the affected pet. Along with canines, heartworms are also seen in mammals such as foxes, wolves, ferrets, and along with mosquitoes; also, the foxes and the coyotes that live in the proximity of the cities are regarded as prime carriers of the disease.

The microfilariae causing heartworm disease in dogs also damages the animal’s immune system. Female adult heartworms are up to 15 – 36 cm, 3 mm wide. Male worms are half the size of female worms. In the USA, Atlantic, Mexico, New Jersey, and Mississippi River areas are more susceptible to heartworm disease in pets. Simultaneously, research has shown that heartworm disease in dogs is observed in all 50 states. 

What are the Key Symptoms of Heartworm Disease in Dogs?

The fatality of heartworm disease in dogs depends upon the number of worms inside the infected canines, the duration of infections, the immunity, and the pet’s activity level. The symptoms of heartworms in dogs can be diversified into four stages. Higher intensity of the symptoms  indicate that the disease severity has worsened. The common symptoms of the disease are:

CoughBased on the disease severity, mild to persistent, dry cough is a common sign seen in dogs with heartworm disease. 
Weight LossSome canines suffering from heartworm have a reduced appetite for food, leading to weight loss. 
 LethargyLethargy or reluctance to activity or exercise is another sign seen in dogs with heartworm disease. If your feet are reluctant to go for their daily walk or fatigued after mild to moderate activity, it may be a sign of heartworm disease.
Swollen RibsIn the middle stage of the disease, as the fluid fills the lungs, the pet’s chest may protrude; you also may observe the bulging appearance of ribs caused by weight loss.  
Respiratory Disorder In the advanced cases, dogs can develop more breathing difficulty and persistent coughing.

In the late stage, more complications emerge; if the stage advances, you can witness the consistent signs of late-stage heartworm disease including abnormal lung sounds, enlarged liver, etc.

What Causes Heartworm Disease in Dogs?

Heartworm lives inside a canine’s body and produces offspring that lead to damage to arteries, heart, and lungs. Even the dead worm can cause severe damage to pet health and quality of life. Heartworm is transmitted via mosquitoes. It transferred the baby worms called microfilaria to an infected animal that circulated in the bloodstream. Microfilaria developed within mosquitoes for approx 10 to 14 days. 

When the carrier mosquitoes bite your pet’s open wounds, the larvae are deposited in the skin. Inside a new host, larvae took around 24 weeks to develop adult heartworms. Adult heartworms live 5 to 7 years in dogs.

The microscopic adult male worms stay in the heart and mate with female worms who remain in the arteries to produce another generation of microfilariae. Each microfilaria will then live for about two months before dying off from natural causes. Once they die, their empty bodies drop off from their host’s body until they are ingested by another mosquito which reinvigorates, mate again, and produce more worms.

We crafted the infographic with the visual illustration of heartworm disease in dogs to offer a crisp idea. Let’s roll through it.

What are the Stages of Heartworms in Dogs?

Ensure to observe the signs of heartworm disease in dogs; when you witness any heartworm symptoms in your pet, consult your vet immediately. You can find a top-rated vet in your area using an online vet directory such as GreatVet; whatever may be the way, a vet consultation is crucial to cure the heartworm in your pet. Upon being left untreated, the ailments can damage a dog’s heart, lungs, liver, and kidneys, eventually causing death. Let’s check out the stages of the illness and it’s severity:

StagesIllness Severity 
Stage- 1In stage one of the illness, you may witness occasional cough in your pet or no symptoms at all. At stage-1 the lavare is yet to form a new generation of microfilariae in the dog’s body, and the disease has not yet progressed. 
Stage- 2In the stage pet mat show, mild to modest symptoms include tiredness and occasional cough. Also, the activity level may be reduced. At this stage, for a longer duration, heartworms are already in the body for antibody production and probable microfilariae production. At stage-2, a vet can detect the disease with blood tests.
Stage-3Stage three is a more serious stage of the disease when the pet displays symptoms such as tiredness even after mild activity and persistent cough. Also, you may witness trouble breathing in your pet or other signs of heart failure.  During this stage, your pet may also cough up blood, and the ailment is evident in x-rays. 
Stage- 4  Stage four of the symptoms is also termed caval syndrome. It is life-threatening, and you need to seek immediate vet attenuation. Testing reveals the impact of the disease with abnormal sounds within the dog’s heart; with treatment, the stage of the illness also holds a high risk of long-term debilitation. Caval syndrome is treated with surgery; however, going by statistics, the stage is fatal and can lead your, furry friend to eternal rest. 

How To Treat Heartworm Disease In Dogs?

The first step in recovering from an infection is to identify it. After identifying the infection in heartworm disease in dogs, the next step is to eliminate the immature worms by killing them while keeping the side effects of the treatment to a minimum.

In treatment for heartworm disease in dogs Immiticide and Diroban are trade names for melarsomine dihydrochloride used. It is an arsenic-containing medicine approved by the FDA to kill adult heartworms in dogs. It is injected deep into the dog’s back muscles to treat dogs with class 1, 2, and 3 heartworm disease that has been stabilized. Microfilariae in the dog’s bloodstream can be eliminated using Advantage Multi for Dogs (imidacloprid and moxidectin). This topical solution is applied to the dog’s skin. 

It is not easy to deal with heartworm infection in dogs. Due to the treatment the dog’s body may turn toxic, and dangerous blood clots to the lungs may occur. Also the entire process of treatment requires multiple veterinary visits, blood tests, x-rays, hospitalization, and injection therapy, which also can be costly on your pocket as a pet owner. 

How to Prevent Heartworm Disease in Dogs

The best preventive measure is to consult your vet as soon as you witness any symptoms. As a preventative measure, vets eliminate the fillare that can grow into adult heartworm. To prevent heartworms in canines, often the pet medical professionals use a product that the FDA has approved. Certain  heartworm preventive products contain ingredients that are also effective against intestinal parasites (such as fleas, ticks, and ear mites). 

However, the best prevention strategy is to administer your dog a preventive medication every month. Ensure to consult your veterinarian if you have any concerns. There are two methods of administering the anti-heartworm drug: a topical liquid applied to the animal’s skin or an oral tablet that can be eaten. Also, vets suggest injection based on the disease severity, which is given every six or twelve months. If you are seeking a top-rated vet in your area to take care of your puffball, you can check out the vets near me within a click without wasting time. 

Final Thought

Heartworm disease in your pet is a matter of concern, and along with the mentioned symptoms, you also may witness signs such as Anemia, Fainting Spells, High Blood Pressure, and Rapid Heart Beat. 

Treatment for heartworm disease also holds certain risk factors. After undergoing the heartworm treatment, they may suffer from anaphylaxis and emboli; also, there is the possibility of abscess formation after the melarsomine injection. 

In addition, the pet also goes through emotional distress,  the severity level impacting the prognosis, and if the ailment is identified sooner and treated, the greater likelihood there is for a good outcome. Also, you must adhere to routine vet check-ups as curing does not indicate immunity from the disease and susceptible to it; hence you must consult your vet for a thorough and round-up preventive care for your pet, ensuring its well-being. 

Heartworm Disease in Dogs: FAQs

  1. Is vaccination available for heartworm disease in canines?

Vaccination is not commercially available for heartworm disease in dogs, but research on its possibility continues. A vet prescribes the current preventative medication for heartworms, and it is available in both oral, topical, or injection format. Many medicines used in heartworm prevention also have additional benefits in treating parasites in the pet. 

  1. Why Do pet parents require a prescription for a pet’s heartworm preventive medication? 

Heartworm prevention medication requires a prescription. According to the U.S. Food & Administration (FDA), heartworm prevention states that the remedy is to be used under the prescription of a licensed veterinarian.

  1. At what age should pet owners be started on heartworm prevention? What particular aspect to consider or know about prevention in my new pet?

According to the American Heartworm Society puppies and kittens can be taken for heartworm prevention at eight weeks of age. Ferrets are started on preventatively when they weigh at least two pounds.

If you have adopted a new puppy, note that the dosage of a heartworm medication depends on body weight, not age. For preventive measures, ensure to bring your pet to the scheduled well-puppy or well-kitten exam, and provide your vet that it is given the right heartworm prophylactic dosage by having your pet weighed at every visit.

  1. Are heartworms more common in some regions of the U.S.? 

Heartworms are prevalent across 50 states; however, a few very high-risk areas are the Atlantic region, Mexico, and the Mississippi River & its river tributaries. Factors that affect the risk of heartworm infection risk include the climate, the species of mosquitoes in the area, the presence of mosquito breeding areas, and the presence of infected animals such as infected dogs, foxes, or coyotes.

  1. What is the life duration of heartworm in a canine? Can a pregnant dog be treated for heartworm disease? 

Inside a dog, a heartworm’s life span is 5 to 7 years. Year-round heartworm prevention is recommended for the pregnant dog; however, it is notable that certain products are not safe during pregnancy. Also, treating a pregnant dog for heartworm diseases may lead to toxic effects on the puppies.

Disclaimer: The content on the site is for educational purposes only, and it does not provide medical advice. The shared information must not be treated as a substitute for or alternative for medical practitioner advice, diagnosis, or treatment. Regarding any concerns about your pet’s health, seeking veterinary guidance is of utmost necessity. Each pet has specific health, fitness & nutrition needs. Do not disregard, avoid or delay pet health-related advice from veterinarians based on reading the information provided on this site.



Alex Schechter

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