Paragonimus spp. is a common parasite of crustacean-eating mammals such as tigers, leopards, domestic cats, dogs, mongooses, opossums and monkeys (reservoir final hosts). The adult flukes live in the lungs and lay eggs that are coughed up through the airways and either expectorated in the sputum or swallowed and defecated. When they reach freshwater, the eggs develop into miracidia that penetrate various species of aquatic snails, where they further develop and reproduce asexually, giving rise to cercariae (larvae). Paragonimus is a rare disease that usually affects young adults between the ages of 15 and 35, although individuals of any age may be affected. Men have an increased risk of developing Paragonimus.
Diagnosis of paragonimiasis is suspected on the basis of the clinical picture, on the anamnestic recall of consuming raw crustaceans, on the detection of eosinophilia, and on typical findings of ultrasound, X-ray, computed tomography or magnetic resonance imaging scans. Tests to rule out tuberculosis should always be conducted. Confirmation of diagnosis relies on different types of diagnostic techniques. Further research is being conducted to determine the drugs for the Paragonimus and how long it can affect humans.