Doctors Find Living Lung Fluke in Woman's Chest
Surgeons documented a live Paragonimus worm during thoracoscopy in a 38-year-old patient who had been admitted twice for recurrent pleural effusion.
Updated on Nov. 7, 2026 in Asthma
Doctors identified a living adult Paragonimus lung fluke inside the chest of a 38-year-old woman during thoracoscopy. The case was published in October 2025 in Infection, Genetics and Evolution, and the patient showed no recurrence over four months of follow-up after further praziquantel treatment.
Why it matters
Paragonimiasis is typically acquired by eating raw or undercooked freshwater crabs and crayfish carrying infective larvae, and the larvae can migrate from the gut through the diaphragm into the lungs. The case shows how a parasitic infection can present as recurrent pleural effusion and be confirmed only by direct visualization of the worm.
The evidence is a single documented case report, with one 38-year-old patient admitted twice within six months for recurrent pleural effusion and followed for four months without recurrence. The extraction provides no comparator cohort, and the route of exposure for this patient remains unreported.
The players
Infection, Genetics and Evolution
A peer-reviewed scientific journal that publishes research on infectious disease, genetics and evolutionary biology, and which carried the published case report.
The details
Blood tests using ELISA detected antibodies against Schistosoma japonicum and sparganum, and during a second admission doctors performed medical thoracoscopy. A living adult Paragonimus worm was identified under a microscope, and metagenomic next-generation sequencing was run on the pleural fluid before the patient received another course of praziquantel.
Timeline
Within six months, the patient was admitted to hospital twice for recurrent pleural effusion.
During the second admission, doctors performed thoracoscopy and identified the living worm.
Over four months of follow-up after further treatment, no recurrence was found.
In October 2025, the case was published in Infection, Genetics and Evolution.
Health Landscape
Human paragonimiasis is classically acquired by eating raw or undercooked freshwater crabs and crayfish carrying infective larvae, which migrate from the intestine through the diaphragm to the lungs. This case documents a living adult worm in the pleural cavity, showing that the parasite's migratory route can produce a presentation resembling recurrent pleural disease.
For people who eat raw or undercooked freshwater crabs or crayfish, the case is a reminder that lung symptoms such as recurrent fluid around the lungs can have a parasitic cause that standard tests may miss. Clinicians evaluating unexplained pleural effusion may need to consider parasitic infection in patients with relevant exposures.
The takeaway
Recurrent pleural effusion with no clear cause can, in rare cases, be parasitic, and direct visualization during thoracoscopy can confirm what blood tests and imaging may not. Anyone with a history of eating raw freshwater crustaceans should mention that exposure to their doctor when lung or chest symptoms persist.
Further reading
For broader background on lung conditions that can mimic or accompany fluid buildup around the lungs, see our Asthma coverage.
Source note: This article includes information reported by The Times of India.
