Paragonimiasis is a global foodborne zoonosis. Overlapping clinical and imaging features with other lung pathologies hamper correct diagnosis and require differential diagnosis.

During 1982–2003, 49,012 samples were referred for immunodiagnosis of helminthiases. We detected paragonimiasis cases by enzyme-linked immunosorbent assay (ELISA). We assessed clinical, radiographical and laboratory characteristics, and diagnostic dilemmas associated with delayed diagnosis.

We analyzed 685 pleuropulmonary paragonimiasis cases. ELISA-positive was 665. Eggs were detected in 50. Symptom duration correlated well with the appearance of chest radiographs; 359 pleural, 33 pleuroparenchymal, and 264 parenchymal lesions (P < 0.001). Twenty-nine had normal chest images. Eosinophilia, seen in 304, was common in pleural and pleuroparenchymal patients (P < 0.05). Chest pain and dyspnea were characteristic for pleurisy patients. Sputum (odds ratios [OR]: 6.79; 95% CI: 4.41–10.47), blood-tinged sputum (OR: 5.62; 95% CI: 3.75–8.42), and foul-odor (OR: 2.70; 95% CI: 1.42–5.16) were significant in parenchymal patients. Delayed diagnosis (119) for ≥ 25 weeks was attributed mainly to misdiagnosis as tuberculosis, malignancy, or chronic obstructive pulmonary disease (COPD) (OR: 111.75; 95% CI: 43.25–288.74).

Variable symptoms and radiographs of pleuropulmonary paragonimiasis depended on the stage of infection. Suspicion of tuberculosis, malignancy, or COPD was major cause of delayed diagnosis.