First evidence of Craspedella pedum (Cannon and Sewell, 1995) (Platyhelminthes: Rhabdocoela) infesting alien red swamp crayfish with white spot syndrome virus infections collected from Thailand

摘要

Red swamp crayfish (Procambarus clarkii) is natively distributed in the tropical fresh water of the Southern Mississippi River, the United States, and Northeastern Mexico. This crayfish is also transported to many countries through commercial trade. The aim of this study was to determine the presence of temnocephalid flatworm (Craspedella pedum) on red swamp crayfish collected from the natural waters of Thailand. At the 34 collection sites, only three P. clarkii were caught in traps from two locations in the north-central Thailand region near the Nan River. A total of 23 C. pedum individuals were found in two P. clarkii individuals collected at the same site. White spot syndrome virus (WSSV) was detected in the gill tissue of those two crayfish and C. pedum using PCR analysis. Morphological and molecular C. pedum data are provided. The result is the first report of temnocephalans with viral infection in alien host from the natural environment of Thailand. Furthermore, it is warning that the invasive crayfish and non-native temnocephalans may be already established in natural freshwater of Thailand.