Dog heartworm infection is caused by the roundworm (nematode) Dirofilaria immitis (the dog heartworm) or another similar roundworm.
Dog heartworm infection is transmitted to people by infected mosquitoes.
Dog heartworms cannot complete their life cycle in people and do not survive for very long in them, so people rarely have symptoms.
If the worm travels to the lungs and dies there, people may cough and have chest pain.
Doctors may discover dog heartworm infection when they see a lump in the lungs on a routine chest x-ray.
No treatment is needed because the infection resolves on its own.
Helminths are parasitic worms that can infect humans and animals. There are 3 types of helminths: flukes (trematodes), tapeworms (cestodes), and roundworms (nematodes). Dirofilaria immitis is a type of roundworm called a filarial worm.
Although people can be infected with dog heartworms, the infection rarely causes symptoms in people because the worms cannot complete their life cycle in them and do not survive for very long.
(See also Overview of Parasitic Infections.)
Transmission of Dog Heartworm Infection
Dog heartworm infection is transmitted when an infected mosquito bites a person and deposits larvae of the worm in the skin. The larvae usually die in the skin. However, sometimes the larvae live long enough to penetrate into the bite wound and travel through the blood to the person's lungs. As they die in the blood vessels of the lungs, they forms a lump (nodule), which may be seen on a chest x-ray. Rarely, larvae travel to the eyes, brain, or testes and form lumps there.
Symptoms of Dog Heartworm Infection
Larvae that die in the lungs may cause no symptoms, but some people have a cough and chest pain. Rarely, they cough up blood.
Diagnosis of Dog Heartworm Infection
Removal and examination of a sample of lung tissue
Doctors may discover dog heartworm infection when they see a lump in a person's lungs on a routine chest x-ray. Because the lump can resemble a cancer, doctors take a sample of the lump (biopsy) and examine it under a microscope to be sure it is not a cancer.
Treatment of Dog Heartworm Infection
Infection resolves on its own
No treatment is needed for infected people. Dog heartworm infection resolves on its own.
