Heartworm Disease In Dogs

Heartworm disease is an extremely dangerous and life-threatening illness that affects animals in the United States and a multitude of other countries. Heartworms are one foot long parasites that can reside in the heart, lungs and adjoining blood vessels of domestic animals, leading to dangerous lung diseases, heart failure and injury to other organs. Heartworm illness is usually associated with dogs, cats, and ferrets, but it has been known to inhabit other mammals species, such as wolves, coyotes, foxes, sea lions, and humans in rare cases. Wild animals like foxes and coyotes that occupy areas close to cities are thought to be significant transmitters of the illness.

The canine species is a natural environment for heartworms, allowing them to grow from juveniles to adults, reproduce, and create new generations. Without any treatment, the number of worms can increase, and canines have had multiple hundreds of parasites in them. Heartworm disease is a long-term problem that can have serious consequences for the cardiovascular system of a canine, including the heart, lungs, and vessels. It can take a toll on the pooch’s wellbeing and well-being even after the parasites have been wiped out. It is optimal to prevent the disease whenever possible and if treatment is necessary, it should be started as promptly as possible.

Contrary to popular belief, feline heartworm disease is distinct from the canine variety. Cats are not usually susceptible to heartworms, and the majority of the heartworms found in cats never make it to adulthood. Adult cats with heartworms often have just one to three worms living in their hearts, and some cats suffering from heartworms do not have any adult worms. Though heartworm disease is not often detected in cats, it is still incredibly significant, as even immature worms can cause cardiac troubles known as heartworm associated respiratory disease (HARD). In addition, the medications administered to cure heartworm contamination in canines cannot be applied to cats, so the only way to safeguard cats from the harms of heartworm sickness is through deterrence.

 

The Heartworm Life Cycle in Dogs

In a canine host suffering from an infection, adult female heartworms emit larval offspring, called microfilariae, into the dog’s circulation. When a mosquito bites a dog that is carrying microfilariae, the mosquito will pick up the infection from the animal. In the next two weeks, the microfilariae residing in the mosquito could turn into infectious larvae, assuming suitable environmental conditions. In order to become contagious, microfilariae must go through a mosquito. When a mosquito carrying the infection bites a canine, the larvae responsible for the infection are transmitted to the dog through the bite mark. The infective larvae of the recently infected pooch take approximately 6 to 7 months to develop into full-grown heartworms. Adult heartworms join together in pairs and the female produces young that enter the dog’s circulatory system, completing the cycle. Have a look at a visual representation of the stages of heartworm development in canines.

Heartworm disease is not infectious, which implies that a canine cannot acquire the illness just by being close to a dog who has it. Heartworm illness is only transmitted via the sting of a mosquito.

A heartworm can survive inside a canine for up to 5 to 7 years. Adult heartworms are similar in appearance to cooked spaghetti, with males generally measuring around 4 to 6 inches and the females typically being between 10 and 12 inches long. The worm count in a dog that has been afflicted with parasites is referred to as the worm burden. Most dogs carry around 15 worms on average, yet the number of worms that can be present can span from as little as one worm up to 250.

 

What are the Signs of Heartworm Disease in Dogs?

At the beginning of the illness, some dogs either have few signs or are asymptomatic. The more time that passes with the infection, the greater the chances of symptoms appearing. Canines that have a lot of activity, dogs that have been greatly affected by heartworms, or those with other medical issues usually exhibit pronounced symptomatic signs.

It is possible to identify heartworm disease by indicators such as a persistent light cough, disinclination to physical activity, tiredness after undertaking only a moderate amount of exercise, reduction in hunger, and losing weight. As heartworm disease progresses, pets may experience heart failure and have an abdominal area that appears swollen from the accumulation of liquids. Canines harboring a great deal of heartworms may have their blood flow suddenly obstructed within their heart, likely creating a potentially deadly cardiovascular shock. This condition is known as caval syndrome and has symptoms that include labored breathing, pale gums, and bloody or dark-brown urine that appears abruptly. Without swift surgical intervention to remove the heartworm obstruction, few canines make it out alive.

 

How is a Dog Tested for Heartworms?

A vet will administer a blood test to determine if a canine has heartworms. An antigen test looks for particular heartworm proteins called antigens that are released into the canine’s bloodstream by female heartworms that are mature. Most of the time, antigen tests are able to precisely identify infections that involve at least one adult female heartworm. It may take up to 5 months for heartworm proteins to show up in a dog’s bloodstream following a bite from a mosquito that is carrying the disease.

Another test detects microfilariae in a dog’s bloodstream. The presence of microfilariae in the bloodstream shows that the dog has an adult heartworm infection, which is the only stage that can mate and create microfilariae. It may take up to 6 months for microfilariae to become present in a dog’s bloodstream after an infected mosquito has bitten it – due to the necessary time for heartworms to mature from an infective larval state to adults, which are then able to reproduce and thus populate the bloodstream with the smaller worms.

 

When Should a Dog Be Tested for Heartworms?

The amount of time between and number of heartworm tests is dependent on an array of factors. Some of these factors include:

The dog’s age when heartworm prevention is started;

• If the owner forgot to give heartworm prevention and for how long;
• If the dog is switched from one type of heartworm prevention to another;
• If the dog recently traveled to an area where heartworm disease is more common; and
• The length of the heartworm season in the region where the dog lives.

Prior to administering heartworm prevention to canines 7 months of age and over, they should be tested for heartworms. A canine may seem sound physically, yet may potentially harbor heartworm parasites internally. If a pup exhibiting indications of heartworm is not analyzed before beginning a preventive treatment, then the pup will keep being plagued with adult heartworms until it becomes unwell enough to demonstrate signs. Heartworm preventives do not kill adult heartworms. It can be harmful or even fatal to administer a heartworm preventative to a canine that has grown-up heartworms. If there are microfilariae present in the pup’s circulatory system, taking the preventive medicine could cause them to pass away all at once, leading to a type of shock response and potentially death.

It is suggested that all canines be examined for heartworm prevention on a yearly basis. It’s essential to discuss with your pup’s vet the optimal time to have a yearly heartworm assessment.

 

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How Significant is my Pet’s Risk for Heartworm Infection?

Different elements need to be taken into account, even if heartworms do not seem to be a problem in your vicinity. It’s possible that the neighborhood you live in has a higher rate of heartworm sickness than you think, or that when you take your pet on trips, you may unintentionally enter an area where heartworm infestation is more prevalent. Heartworm illness is migrating to different parts of the nation annually. Neglected and wandering dogs as well as certain wild animals including coyotes, wolves, and foxes may contain heartworms. Mosquitoes that have been carried to new areas by the wind and the transportation of pets, who have heartworm disease, to places they weren’t before can also help spread the condition. This was noticed in the aftermath of Hurricane Katrina, when almost a quarter of a million pets, some of them with heartworm, were given new homes and were transferred throughout the US.

Heartworm disease is present in all of the United States, and it is not possible to know what is likely to cause it. The rates of infection can be drastically different from year to year and even within communities due to various factors, from changes in the climate to the introduction of animal carriers. Mosquitoes that are carrying a disease can enter both inside and outside dwellings, making both animals living indoors and outdoors susceptible.

The American Heartworm Society proposes that owners of pets adhere to the “think 12” rule, which entails testing their animal for heartworm each year and providing heartworm prevention annually.

 

What Happens if my Dog tests Positive for Heartworms?

Nobody likes to learn that their canine has heartworm, however the great news is that a lot of dogs infected with it can be dealt with effectively. The primary objective is to steady your canine if they have indications of affliction, then eliminate all adult and young parasites, while limiting the side effects of the treatment.

Here’s what you should expect if your dog tests positive:

• Confirm the diagnosis. Once a dog tests positive on an antigen test, the diagnosis should be confirmed with an additional—and different—test. Because the treatment regimen for heartworm is both expensive and complex, your veterinarian will want to be absolutely sure that treatment is necessary.
• Restrict exercise. This requirement might be difficult to adhere to, especially if your dog is accustomed to being active. But your dog’s normal physical activities must be restricted as soon as the diagnosis is confirmed, because physical exertion increases the rate at which the heartworms cause damage in the heart and lungs. The more severe the symptoms, the less activity your dog should have.
• Stabilize your dog’s disease. Before actual heartworm treatment can begin, your dog’s condition may need to be stabilized with appropriate therapy. In severe cases of heartworm disease, or when a dog has another serious condition, the process can take several months.
• Administer treatment. Once your veterinarian has determined your dog is stable and ready for heartworm treatment, he or she will recommend a treatment protocol involving several steps. The American Heartworm Society has guidelines for developing this plan of attack. Dogs with no signs or mild signs of heartworm disease, such as cough or exercise intolerance, have a high success rate with treatment. More severe disease can also be successfully treated, but the possibility of complications is greater. The severity of heartworm disease does not always correlate with the severity of symptoms, and dogs with many worms may have few or no symptoms early in the course of the disease.
• Test (and prevent) for success. Approximately 6 months after treatment is completed, your veterinarian will perform a heartworm test to confirm that all heartworms have been eliminated. To avoid the possibility of your dog contracting heartworm disease again, you will want to administer heartworm prevention year-round for the rest of his life.

 

Is There a Treatment for Heartworm Disease in Dogs?

Melarsomine dihydrochloride (marketed under the trade names Immiticide and Diroban) is a medication including arsenic that has been approved by the FDA to kill grown-up heartworms in canines. This medicine is administered via a deep needle into the dogs’ back muscles to manage stabilized Class 1, 2, and 3 heartworm disease. A different medication, called Advantage Multi for Dogs (containing imidacloprid and moxidectin), has been sanctioned by the FDA to eradicate microfilariae from a canine’s bloodstream. A topical solution, Advantage Multi for Dogs, is applied directly to the canine’s skin.

Curing heartworm illness is an unpleasant experience both for the pooch and the proprietor’s bank account. The medicine involved in the treatment may poison the canine’s organism and lead to severe side effects, including the formation of deadly blood clots in the animal’s lungs. Getting medical care for an animal is costly due to having to take them to the vet multiple times, getting their blood taken, doing x-rays on them, admitting the pet to the hospital, and having to administer multiple injections.

 

Is there a Vaccine for Heartworm Disease?

At the moment, there is no vaccine available which can be bought to protect against heartworm in dogs or cats. However, research scientists are looking at this possibility. At present, avoiding heartworm disease can exclusively be done via the routine and suitable utilization of prophylactic medications, which your veterinarian will provide. These medications can be taken in three different ways: a chewable pill once a month, a topical application once a month, and an injection twice a year. Consult with your veterinarian to decide which choice is most suitable for your pet. Many of the drugs have the bonus of stopping other parasites too.

 

The Best Treatment is Prevention!

Many products are FDA-approved to prevent heartworms in dogs. All require a veterinarian’s prescription. The majority of products are administered monthly, either as a topical solution to be rubbed into the skin or taken orally in the form of a pill. Both chewable and non-chewable oral tablets are available. A veterinary must administer a shot to the skin every 6 or 12 months of a single product. Some heartworm preventives include components which can be effective against certain intestinal parasites (including roundworms and hookworms) and other invasions (including fleas, ticks, and ear mites).

Year-round prevention is best! Speak with your dog’s doctor to figure out what kind of preventative is most beneficial for your canine.