Presence of three distinct genotypes within the Paragonimus westermani complex in northeastern India.

The name Paragonimus westermani (Kerbert, 1878) is commonly applied to members of a species complex that includes the well-known Asian lung fluke of medical and veterinary importance. Unambiguous molecular and morphological evidence showing the presence of a member of the complex in India has recently been published. In the present study we report the occurrence of 2 more members of the P. westermani complex in northeastern (NE) India. Surveys of the freshwater crabs Maydelliatelphusa lugubris in NE India revealed 2 morphologically distinct types of lung fluke metacercariae. Phylogenetic analyses, using DNA sequences from ITS2, 28S and cox1 gene regions indicate that these lung metacercariae belong to P. westermani complex. Type 1 metacercariae have a more basal position within the complex whereas type 2 metacercariae are closely related to the relatively derived forms of P. westermani from NE Asia (Japan, Korea, China) and Vietnam. A third type of metacercaria (type 3), detected in another crab host, Sartoriana spinigera in Assam, was phylogenetically close to P. siamensis, also a member of the P. westermani group. Molecular evidence has demonstrated the existence of 3 genotypes of lung flukes within the Paragonimus westermani complex in NE India. Two of these were previously unknown.

A rodent model for pulmonary paragonimiasis.

This study reports a model of pulmonary paragonimiasis in outbred Wistar rats using the Indian strain of Paragonimus heterotremus isolated from the fresh water crab Barytelphusa lugubris collected from Arunachal Pradesh, India. Feeding metacercariae to the rats led to encapsulated adult worms in the lungs and pleural cavity. Some flukes migrated to the skeletal muscles of the hosts where they remained underdeveloped as immature flukes.