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Dirofilariasis

(Dog Heartworm Infection)

by Richard D. Pearson, MD

Dirofilariasis is a filarial nematode infection (see Overview of Filarial Nematode Infections) with Dirofilaria immitis, the dog heartworm, which is transmitted to humans by infected mosquitoes.

Symptomatic human infection is very rare, but larvae may become encapsulated in infarcted lung tissue and produce well-defined pulmonary nodules.

Patients may have chest pain, cough, and occasionally hemoptysis. Many patients remain asymptomatic, and a pulmonary nodule, which may suggest a tumor, is discovered during routine chest x-ray.

Diagnosis is by histologic examination of a surgical specimen.

No treatment is indicated in humans; infection is self-limited.

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