Paragonimiasis is a parasitic infection caused by the Paragonimus worm, a parasite more commonly known as a lung fluke. These parasitic worms are endemic in various Asian countries, especially Korea, Japan, Taiwan, the highlands of China, and the Philippines.
Last Updated: February 25, 2024

The disease is caused by the parasite Paragonimus westermani, as well as eight other Paragonimus species. These parasites are transmitted to humans after eating infected freshwater or mountain crabs.

Early in the infection, there are usually no symptoms. When the worms finally reach the lungs, symptoms may include: • Dry cough (cough with little to no phlegm) • Phlegm that is stained with blood, or is rust-colored and smells fishy • Chest or back pain • Difficulty breathing • Fever Symptoms and signs of the disease resemble those of tuberculosis or lung cancer; thus, paragonimiasis should always be suspected in patients with tuberculosis who are not responsive to responding to antibiotic treatment.

A diagnosis of Paragonimiasis can be made based on a person’s history of eating raw or undercooked crabs and, with the presence of the symptoms mentioned above. The diagnosis can then be confirmed by identifying eggs of the parasite in a person’s sputum or stool, or by testing the blood for presence of antibodies against the parasite. Praziquantel, which is currently available only in DOH facilities in areas where the parasite is common, is used to treat the disease. It is usually given orally in 3 doses for two days.

The following strategies can help prevent paragonimiasis infections in a community: • proper sanitation of surroundings and adequate hand hygiene • cooking food, especially crustaceans like crabs, very well • preventive medications like triclabendazole may be considered in areas where cases of paragonimiasis are significantly higher • treatment of infected animals, such as pigs, cats, and dogs
Last Updated: February 25, 2024