Hypolobocera guayaquilensis (Decapoda: Pseudothelphusidae): A New Crab Intermediate Host of Paragonimus mexicanus in Manabí Province, Ecuador

Resumen

To determine that <i>Paragonimus</i> sp. is actively transmitted in a tropical area of the Pacific region of Ecuador where human cases of pulmonary paragonimiasis have recently been documented, a total of 75 freshwater crabs were collected from 2 different streams in the Pedernales area of Manabí Province, Ecuador. All collected crabs were identified as <i>Hypolobocera guayaquilensis</i> based on morphological characteristics of the male gonopods. The hepatopancreas of each crab was examined by compressing it between 2 glass plates followed by observation under a stereomicroscope. Excysted <i>Paragonimus</i> metacercariae were detected in 39 (52.0%) crabs and their densities varied from 1 to 32 per infected crab. There was a positive relationship between crab size and metacercarial density. Sequences of the second internal transcribed spacer region of the ribosomal RNA gene of the <i>Paragonimus</i> metacercariae obtained in this study were identical to those of <i>Paragonimus mexicanus</i> deposited in the DDBJ/EMBL/GenBank database. Thus, the present study is the first to confirm that the crab species <i>H. guayaquilensis</i> is the second intermediate host of <i>P. mexicanus</i> in Manabí Province, Ecuador. Because this crab might be the possible source of human infections in this area, residents should pay attention to improper crab-eating habits related with a neglected parasitic disease, i.e., paragonimiasis.