Triploidy in Paragonimus westermani.

The finding of triploid and diploid forms of Paragonimus westermani in Japan has caused tremendous controversy over the identity and speciation of this parasite. Should these two genetically different forms be given different specific names? Hirohiso Hirai and Takeshi Agatsuma have studied the lung flukes by using cytogenetic techniques and zymodeme analysis. In this article, they briefly compare triploid P. westermani with the diploid form and develop a hypothesis for the mechanism and origin of triploidy.