More than 30 species of trematodes (flukes) of the genus Paragonimus have been reported which infect animals and humans.  Among the more than 10 species reported to infect humans, the most common is P. westermani, the oriental lung fluke. While P. westermani occurs in the Far East, other species of Paragonimus are encountered in Asia, the Americas, and Africa.

Symptoms

The acute phase (invasion and migration) may be marked by diarrhea, abdominal pain, fever, cough, urticaria, hepatosplenomegaly, pulmonary abnormalities, and eosinophilia.  During the chronic phase, pulmonary manifestations include cough, expectoration of discolored sputum, hemoptysis, and chest radiographic abnormalities.  Extrapulmonary locations of the adult worms result in more severe manifestations, especially when the brain is involved.

Diagnosis

Diagnosis is based on microscopic demonstration of eggs in stool or sputum, but these are not present until 2 to 3 months after infection.  (Eggs are also occasionally encountered in effusion fluid or biopsy material.)  Concentration techniques may be necessary in patients with light infections.  Biopsy may allow diagnostic confirmation and species identification when an adult or developing fluke is recovered.

Treatment

Praziquantel* is the drug of choice to treat paragonimiasis.  Bithionol is an alternative drug for treatment of this disease.

References

CDC