A 40-year-old male farmer from Punjab with chronic cough and haemoptysis has sputum microscopy showing golden-brown operculated eggs with a shouldered operculum (22–34 × 12–20 µm). He regularly eats freshwater crabs from local fields. What is the diagnosis?

• A Pulmonary tuberculosis — sputum AFB smear is required to differentiate
• B Clonorchis sinensis — acquired from raw freshwater fish, causes biliary disease
• C Fasciolopsis buski — large intestinal trematode, ova found in stool only
• D Paragonimiasis (Paragonimus westermani) — acquired by eating raw/undercooked freshwater crabs or crayfish (second intermediate host) ✓

Explanation

Paragonimus westermani is a lung fluke whose eggs are operculated, golden-brown, 'shouldered' (shouldered operculum = a rim at the opercular end), measuring 80–120 × 45–60 µm (actually larger — commonly described as 80–118 × 48–60 µm); they appear in sputum (or stool if swallowed). Infection occurs by eating raw or inadequately cooked freshwater crabs/crayfish (second intermediate host). Clinical features include haemoptysis, chronic cough, and pleural effusion mimicking TB. Clonorchis affects the biliary tract; Fasciolopsis is an intestinal trematode.

Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.