Cardiac Dirofilariasis (Parasitic Infection with Heartworms, Dirofilariae) in Dogs
- Occurrence: rarer
- Location of illness: Chest
Cardiac dirofilariasis, also known as heartworm disease, is a severe parasitic infection caused by the roundworm Dirofilaria immitis. These worms primarily infest the heart and pulmonary arteries of dogs and, if left untreated, can lead to serious health problems or even Death.
The most important facts at a glance
Cardiac dirofilariasis in dogs is caused by parasitic nematodes called heartworms that settle in the cardiovascular system. The parasite is transmitted through mosquito bites that inject microscopic larvae, called microfilariae, into the dog. These develop into adult worms in the dog, which infest the heart and blood vessels. The risk of infection is particularly high in warm, humid climates.
Symptoms include chronic Cough, shortness of breath, Weight loss, and heart murmurs. Severe cases can cause Cardiovascular collapse or sudden Death. Diagnosis is made through clinical signs, blood tests, and imaging procedures such as X-rays or ultrasound. Antigen tests and blood tests help confirm the infection. Treatment includes medications to kill the worms and requires restricted activity of the dog to avoid complications. In some cases, additional medications are used against microfilariae or secondary infections.
The prognosis depends on the stage of infection at diagnosis. Early detection and treatment improve the chances of recovery, while advanced infections are more difficult to treat. Prevention is crucial and includes regular preventive medications and mosquito control measures. Regular veterinary examinations are important to monitor the dog’s health and respond early to infections. A comprehensive prevention plan in collaboration with a veterinarian offers the best protection against this disease.
Causes
Heartworms are parasitic nematodes that settle in the cardiovascular system of dogs. The life cycle of Dirofilaria immitis begins when an infected mosquito bites a dog and transmits microscopic larvae, called microfilariae. These microfilariae develop in the dog’s body over several months into adult worms that eventually infest the heart and adjacent blood vessels.
Mosquitoes are the primary vectors of heartworm disease. In endemic areas, especially in warm, humid climates, the risk of transmission is particularly high. Factors such as temperature and humidity influence the development rate of microfilariae in the mosquito, which in turn affects the frequency of infections in dogs.
Once in the dog’s body, the larvae migrate through the bloodstream and settle in the lungs and heart. There, they mature into adult worms within about six months, which can grow up to 30 cm long. These adult worms can survive in the host for several years, causing significant damage to the cardiovascular system.
Symptoms
- Chronic Cough
- Cardiac Dirofilariasis (Parasitic Infection with Heartworms, Dirofilariae)
- Cardiac Dirofilariasis (Parasitic Infection with Heartworms, Dirofilariae)
- Cardiac Dirofilariasis (Parasitic Infection with Heartworms, Dirofilariae)
- Cardiac Dirofilariasis (Parasitic Infection with Heartworms, Dirofilariae)
- Cardiac Dirofilariasis (Parasitic Infection with Heartworms, Dirofilariae)
- Cardiac Dirofilariasis (Parasitic Infection with Heartworms, Dirofilariae)
- Cardiac Dirofilariasis (Parasitic Infection with Heartworms, Dirofilariae)
- Cardiac Dirofilariasis (Parasitic Infection with Heartworms, Dirofilariae)
- Cardiac Dirofilariasis (Parasitic Infection with Heartworms, Dirofilariae)
- Cardiac Dirofilariasis (Parasitic Infection with Heartworms, Dirofilariae)
- Cardiac Dirofilariasis (Parasitic Infection with Heartworms, Dirofilariae)
- Cardiac Dirofilariasis (Parasitic Infection with Heartworms, Dirofilariae)
- Cardiac Dirofilariasis (Parasitic Infection with Heartworms, Dirofilariae)
- Cardiac Dirofilariasis (Parasitic Infection with Heartworms, Dirofilariae)
The symptoms of heartworm disease can vary depending on the severity of the infection and the number of worms. In early stages, dogs may be asymptomatic or show only minor signs. However, serious symptoms can occur as the infection progresses.
Common symptoms include chronic Cough, shortness of breath, Lethargy after moderate activity, and loss of appetite. Some dogs may also experience Weight loss, Pallor of the mucous membranes, and an enlarged liver. In severe cases, it can lead to Heart failure or a blockage of the large blood vessels, which can lead to a sudden Cardiovascular collapse or even Death.
It is important to note that some dogs may show few or no signs despite a significant heartworm burden. This makes regular check-ups and tests particularly important to allow early diagnosis and treatment.
Diagnosis
The diagnosis of heartworm disease is usually based on a combination of clinical signs, blood tests, and imaging procedures. One of the most common tests is the antigen test, which detects the presence of proteins secreted by adult female heartworms. This test is very reliable and can detect an infection early on.
In addition to antigen tests, blood tests can be performed to detect microfilariae. These tests help confirm the presence of heartworm larvae in the blood. In some cases, an X-ray or ultrasound of the heart may also be performed to assess the extent of the infection and check the condition of the heart and pulmonary arteries.
Occasionally, further diagnostic procedures may be necessary, especially in advanced cases or when complications have occurred. A comprehensive examination by a veterinarian is essential to make an accurate diagnosis and develop an appropriate treatment plan.
Therapy
Treatment for heartworm disease is complex and requires a careful, step-by-step approach to minimize the risk of complications. The first step is usually to kill the adult worms with a drug specifically targeting Dirofilaria immitis. Melarsomine is one of the most common drugs for this purpose and is usually administered through a series of injections.
In addition to drug treatment, it is important to severely restrict the dog’s activity during the recovery phase to minimize the risk of embolism from dying worms. This rest period can last several weeks to months, depending on the severity of the infection and the dog’s response to treatment.
In some cases, additional treatment may be needed to eliminate microfilariae in the blood or treat secondary infections. Antibacterial drugs such as doxycycline may also be used to kill bacteria that live in symbiosis with heartworms and may contribute to the pathogenesis of the disease.
Treatment should always be under the supervision of a veterinarian, as the therapy is associated with risks and must be individually tailored to the dog.
Prognosis and follow-up care
The prognosis for dogs with heartworm disease depends on various factors, including the stage of the disease at the time of diagnosis, the number of worms, and the presence of complications. In early stages, if the infection is detected and treated in time, the prognosis is usually good, and many dogs can recover completely.
In advanced stages or with severe heartworm burden, the prognosis may be more guarded. Complications such as Heart failure or severe lung damage can complicate treatment and reduce the chances of survival. Early diagnosis and a targeted treatment plan are crucial to minimize the risk of serious consequences.
Even after successful treatment, regular follow-up care is important to ensure that no new infections occur and to monitor the dog’s long-term health.
Prevention
Prevention of heartworm disease is crucial to minimize the risk of infection. There are several effective preventive medications that can be administered regularly to prevent the development of heartworms. These preparations kill the microfilariae before they can develop into adult worms.
Preventive medications include monthly tablets or spot-on preparations that can be prescribed by a veterinarian. It is important to administer these preventive measures consistently throughout the year, especially in regions with a high risk of infection.
In addition to drug prevention, mosquito control measures can be helpful in reducing the risk of bites and thus infections. These include the use of mosquito repellents and avoiding outdoor stays in mosquito-rich areas during dusk and early morning.
Regular veterinary examinations and tests are also crucial to monitor the dog’s health and respond early to signs of infection. A comprehensive prevention plan developed in collaboration with a veterinarian offers the best protection against heartworm disease.