Paragonimus westermani, commonly known as the lung fluke, is a parasitic flatworm that causes paragonimiasis, a disease that primarily affects the lungs but can also spread to other organs. It is commonly found in Asia and parts of Africa and the Americas, where consumption of undercooked freshwater crustaceans like crabs or crayfish can lead to infection.
Humans become infected when they ingest the parasite’s larvae, which are encysted in the tissues of the contaminated crustaceans. Once ingested, the larvae migrate from the intestines through the abdominal wall, into the diaphragm, and eventually reach the lungs, where they mature into adult flukes. The flukes then lay eggs in the lungs, which are either coughed up and swallowed or passed in stool.
Paragonimiasis presents with a range of symptoms, primarily respiratory. In the acute phase, symptoms can include fever, abdominal pain, and cough. In chronic cases, individuals may experience persistent coughing with blood-tinged sputum, chest pain, and shortness of breath, mimicking conditions like tuberculosis or pneumonia. If the flukes migrate to other organs, such as the brain, the condition can lead to neurological symptoms.
Treatment typically involves antiparasitic medications such as praziquantel or triclabendazole, which are effective against the adult flukes. Preventive measures include thoroughly cooking freshwater crustaceans and improving food safety practices in endemic regions.
