Enterocytozoon hepatopenaei (EHP), the etiologic agent of Hepatopancreatic Microsporidiosis (HPM), continues to affect shrimp production worldwide. The parasite is known to infect two commercially important marine penaeid species, Pacific white shrimp (Penaeus vannamei) and blue shrimp (Penaeus stylirostris), as well as the freshwater prawn (Marcobrachium rosenbergii). As farmers continue to practice polyculture, it becomes increasingly important to investigate the possibility of HPM transmission among farmed species of crustaceans.
We describe here a simple challenge method to determine the susceptibility of P. stylirostris to EHP and its potential for horizontal transmission of EHP to P. vannamei. To determine the susceptibility of P. stylirostris, EHP inoculum was directly injected into the hepatopancreas of Specific Pathogen Free (SPF) P. stylirostris. Seventeen days post-injection, the EHP-injected P. stylirostris were divided into two groups. In Group 1, ten P. stylirostris were cohabitated with fifty SPF P. vannamei. In Group 2, the hepatopancreas was excised from two P. stylirostris, minced, and used to orally challenge ten SPF P. vannamei. The data gathered provides insight into the possibility of EHP susceptibility in P. stylirostris, and transmission potential of EHP from P. stylirostris to P. vannamei via cohabitation as well as oral challenge.
Key words: Penaeus vannamei, Penaeus stylirostris, Enterocytozoon hepatopenaei, cross-species transmission vector, EHP