Hepatopancreatic microsporidiosis (HPM) caused by Enterocytozoon hepatopenaei (EHP) is a newly emerging disease of cultivated shrimp in Asia. Current evidence indicates that it can be associated with severe growth retardation that may not be clearly evident until the second month of culture and that it may even cause low continuous mortality in the case of very severe infections.
Here we present a new method for detecting Enterocytozoon hepatopenaei (EHP) that has superior specificity to the first generation SSU-PCR developed in 2009 when the genetic information of EHP was still limited. Due to the urgency in stemming losses to HPM, we have decided to release this method for free, non-commercial use to the global shrimp farming community.
The second generation EHP detection method presented here is based on a gene encoding a spore wall protein (SWP) of EHP (SWP-PCR). Results from our laboratory work revealed, in contrast to SSU-PCR, that the SWP-PCR method did not give cross reactions with DNA from crabs infected with H. eriocheir and E. canceri. From these results, we recommend that the new SWP-PCR method replace the first generation SSU-PCR method.
The sequences of the primers for the SWP-PCR method (nested PCR) are given below and can be used freely for non-commercial applications to detecting EHP. Please contact Centex Shrimp (ornchuma.its 'at' mahidol.ac.th) to obtain a free positive control plasmid (pGEM-EHPSWP).