GENERAL SANTOS CITY (MindaNews / 20 December) — Freshwater crabs in Mindanao have been found to carry DNA of the lung-fluke parasite Paragonimus westermani, which can cause illness if crabs are eaten raw or undercooked, scientists reported.
Researchers from the Philippine Genome Center (PGC) – Mindanao detected the parasite in crab samples collected in Davao Oriental.
Their study, published in December 2025 in the journal Parasitologia, suggests that Isolapotamon species, a genus of crabs native to Mindanao, may be a previously unrecognized intermediate host for the parasite.
In their tests, scientists analyzed 11 freshwater crabs and found parasite DNA in five. All infected crabs belonged to the Isolapotamon genus.
The PGC Mindanao team said the finding could help explain how the parasite survives in local rivers and streams.
How the parasite infects humans
Paragonimus westermani can cause paragonimiasis, a lung disease that develops when people eat raw or undercooked freshwater crabs or crayfish carrying the parasite’s larvae, according to the World Health Organization (WHO).
After ingestion, the parasite’s larvae travel from the diaphragm through the body and to the lungs, where they grow into adult worms.
In August 2025, the Department of Health (DOH) – Bicol Center for Health Development warned residents to avoid consuming raw or undercooked crustaceans. Infection can trigger chronic cough, chest pain, fever, and fatigue. Health experts say these symptoms are often mistaken for tuberculosis, which can delay proper diagnosis and treatment.
“People often confuse paragonimiasis with tuberculosis, which delays proper treatment,” Dr. Xavier Vallejo, a medical officer with DOH-Bicol, said during a press conference, according to a Manila Bulletin report.
Why it matters
Paragonimiasis is classified by the WHO as a neglected tropical disease (NTD), infections that mainly affect rural or marginalized communities with limited access to healthcare and education about disease prevention.
Experts noted that identifying Isolapotamon as a host may help authorities monitor the parasite and raise public awareness in communities that eat freshwater crabs.
“These findings highlight health risks from consuming undercooked crabs and support community awareness, food safety, and disease prevention,” PGC – Mindanao said in a December 19 Facebook post.
Health authorities advise thoroughly cooking freshwater seafood, such as by boiling or steaming, to prevent infection. ( Guia A. Rebollido / MindaNews )
