Only you and your family live in your furry friend’s heart! Don’t let canine heartworm disease affect this relationship. Learn everything about this disease and how to prevent it from affecting your family!
Next, learn what canine dirofilariasis is , also known as parasitic heart disease, how your furry friend can get it, whether it is serious or not, how to prevent it and whether it can be cured.
Causative agent and mode of transmission of dirofilariasis
Considered a cardiopulmonary parasitic disease, it mainly affects dogs. The causative agent of canine heartworm disease is Dirofilaria immitis , a nematode parasite similar to roundworm, but which lodges in the heart of dogs when it reaches adulthood.
It is transmitted through the bite of mosquitoes, such as Aedes, Anopheles and Culex, that have bitten another previously infected host. From then on, a new cycle of the disease begins, which occurs as follows:
- a mosquito bites an animal with canine dirofilariasis, ingesting the microfilariae (first-stage larvae) of D. immitis present in the animal’s bloodstream;
- with the mosquito serving as an intermediate host, the larvae will develop in approximately two weeks and migrate from the thorax to the biting apparatus, where they are released through bites;
- Once in the healthy dog’s bloodstream, the larvae go to the subcutaneous and muscular tissue, where they become young adults in three to four days;
- After approximately 100 days, the larvae reach the heart, lodging themselves in the host’s right ventricle and pulmonary arteries. There, they reach sexual maturity, mate and release new microfilariae into the host’s bloodstream, beginning a new cycle.
Amanda Gomes, a veterinarian at Petz, explains that these larvae only reach the peripheral bloodstream between six and eight months after infection. This means that before this period it is not possible to detect the disease through blood tests .
Symptoms of Canine Heartworm Disease
According to Dr. Amanda, “the severity of the disease is directly related to the number of worms the carrier has, the duration of the infection and the individual response of the host”.
Therefore, it is difficult to know when a dog has heartworm disease, since newly infected dogs are almost always asymptomatic. This makes the disease silent, chronic and very serious, as symptoms only appear when it is advanced.
As the disease progresses, however, the owner may notice some symptoms of canine heartworm disease . They start out mild and, over time, become recurrent and more easily noticed. The most common are:
- chronic cough;
- exercise intolerance;
- weakness;
- tachypnea (rapid breathing);
- dyspnea (rapid, shallow breathing);
- weight loss.
According to Amanda, the most severe symptoms are related to the greater presence of adult worms in the pulmonary arteries. “It results in chronic pulmonary hypertension and leads to right-sided congestive heart failure,” she explains. “This can even cause the pet’s death,” she adds.
Diagnosis and treatment of heartworm disease
As always, the earlier the disease is diagnosed, the faster, easier and more effective the treatment will be. In the case of heartworm, several tests can be performed to identify the parasite. Among them, an echocardiogram and blood tests can detect both the parasite and antibodies against it.
Other tests, such as blood count, serum biochemistry, urinalysis and chest x-rays, may also be requested by the veterinarian in order to check the severity of the changes caused by heartworm disease in the pet.
“If diagnosed early, heartworm disease can be treated successfully, resulting in a cure without any after-effects,” says Dr. Amanda. The veterinarian explains that there is treatment for canine heartworm disease and it is usually done with adulticides and microfilaricides.
While the former kill adult larvae, the latter, as the name suggests, take care of the microfilariae. Because it has many adverse effects, including the risk of embolism from dead worms, adulticide treatment should only be used on dogs in adequate physical condition.
Surgery to remove adult canine heartworm worms is indicated when caval syndrome occurs. That is, when there is a blockage of the vena cava, making it necessary to immediately reestablish its blood flow.
Prevention of canine heartworm disease
For any disease, the best medicine is still prevention. It’s no different with heartworm! The veterinarian explains that canine dirofilariasis can be cured , and the best solution would be to control the intermediate hosts: mosquitoes.
“Since this is quite complicated, the ideal is to prevent the dog from being bitten by the vector,” he warns. This is done by using repellent collars or topical repellents. In addition, there are pills that are used periodically so that, if the pet is bitten, the larvae die when they enter its bloodstream.
There is also a vaccine against canine heartworm disease . It can be administered to dogs from six months of age and lasts for 12 months. Therefore, it must be reapplied annually.
Another good news is that stores like Petz already have several repellent products that are safe for your furry friends. Options include collars, pipettes to use on the skin, repellents for the home, among others.