Detection of Paragonimus metacercariae in the Japanese freshwater crab, Geothelphusa dehaani, bought at retail fish markets in Japan.

摘要

Metacercariae, the encysted larval stage of flukes capable of infecting the final and/or paratenic hosts, of Paragonimus miyazakii and of both diploid and triploid forms of P. westermani are found in the Japanese freshwater crab, Geothelphusa dehaani, which acts as the second intermediate host in Japan. This crab is known as Sawagani in Japanese and is widely distributed in Japan, from Hokkaido to Kyushu islands, including Yakushima Island. Both Paragonimus spp. are known to be medically important causes of human infection, although the respiratory symptoms that develop in patients vary according to the form and species of the causative lung fluke. Chronic cough with rusty-colored sputum is the most common symptom of patients infected with the triploid form of P. westermani, while infection with P. miyazakii and the diploid form of P. westermani usually causes pleural effusion without remarkable lesions in the lung parenchyma (1).