What are the clinical signs of heartworm disease in humans?

Heartworm disease in humans, caused by the larvae of the parasite Dirofilaria immitis, can present with a range of signs, primarily due to the response of the immune system to the migrating larvae. One of the prominent clinical manifestations is the formation of pulmonary nodules in the lungs, which can occur as the larvae migrate through the body. These nodules may be identified through imaging studies such as chest X-rays and can sometimes be mistaken for other lung pathologies.

This phenomenon occurs because the body attempts to encapsulate the larvae, leading to the development of these nodules. The pulmonary emboli caused by adult heartworms typically do not result in direct impacts on human health as seen in dogs, but can produce localized inflammation. This is a key indicator of heartworm disease in humans and is directly linked to the parasite's lifecycle and its effects on the lung tissue.

The other clinical signs associated with heartworm disease in humans, such as fever, chills, chest pain with cough, as well as nausea and vomiting, tend to be more nonspecific or associated with other conditions rather than being definitive indicators of heartworm disease. Therefore, the formation of pulmonary nodules is the most specific and relevant clinical sign that indicates the presence of heart