title: Dense populations of the microsporidian Enterocytozoon hepatopenaei (EHP) in feces of Penaeus vannamei exhibiting white feces syndrome and pathways of their transmission to healthy shrimp.
abstract: White feces syndrome (WFS) is an emerging problem for penaeid shrimp farming industries in SE Asia countries, Thailand, Malaysia, Vietnam, Indonesia, China, and in India. This occurrence of this syndrome is usually first evidenced by the appearance of white fecal strings floating on surface of the shrimp ponds. The gross signs of affected shrimp include the appearance of a whitish hindgut and loose carapace, and it is associated with reduced feeding and growth retardation. To investigate the nature of the white feces syndrome, samples of white feces and shrimp hepatopancreas tissue were collected from Penaeus vannamei in affected farms in Indonesia, and these were examined histologically. Within the white feces, we found densely packed spores of the microsporidian Enterocytozoon hepatopenaei (abbreviated as EHP) and relatively fewer numbers of rod-shaped bacteria. From WFS ponds, hepatopancreas samples form 30 individual shrimp were analyzed by histology and in situ hybridization. The results showed that all of the shrimp examined were infected with EHP accompanied by septic hepatopancreatic necrosis (SHPN). Midgut epithelial cells were also infected and this increased the number of tissue types being affected by EHP. By PCR, EHP was detected in all the samples analyzed from WFS-affected ponds, but not in those sampled from healthy shrimp ponds. To determine the modes of transmission for this parasite, we performed feeding and cohabitation bioassays, the results showed that EHP can be transmitted through per os feeding of EHP-infected hepatopancreas tissue to healthy shrimp and through cohabitation ofinfected and healthy shrimp. In addition, we found the use of Fumagillin-B, an antimicrobial agent, was ineffective in either reducing or eliminating EHP in infected shrimp.
authors.affiliation: Aquaculture Pathology Laboratory, School of Animal & Comparative Biochemical Sciences, University of Arizona, Tucson, AZ 85721, USA. Electronic address: fengjyu@u.arizona.edu.
authors.forename: Kathy F J
authors.initials: KFJ
authors.lastname: Tang
authors.affiliation: Aquaculture Pathology Laboratory, School of Animal & Comparative Biochemical Sciences, University of Arizona, Tucson, AZ 85721, USA.
authors.forename: Jee Eun
authors.initials: JE
authors.lastname: Han
authors.affiliation: Aquaculture Pathology Laboratory, School of Animal & Comparative Biochemical Sciences, University of Arizona, Tucson, AZ 85721, USA.
authors.forename: Luis Fernando
authors.initials: LF
authors.lastname: Aranguren
authors.affiliation: Aquaculture Pathology Laboratory, School of Animal & Comparative Biochemical Sciences, University of Arizona, Tucson, AZ 85721, USA.
authors.forename: Brenda
authors.initials: B
authors.lastname: White-Noble
authors.affiliation: Aquaculture Pathology Laboratory, School of Animal & Comparative Biochemical Sciences, University of Arizona, Tucson, AZ 85721, USA.
authors.forename: Margeaux M
authors.initials: MM
authors.lastname: Schmidt
authors.affiliation: Faculty of Veterinary Science, Prince of Songkla University, Hatyai, Songkhla 90110, Thailand.
authors.forename: Patharapol
authors.initials: P
authors.lastname: Piamsomboon
authors.affiliation: Lampung, Indonesia.
authors.forename: Eris
authors.initials: E
authors.lastname: Risdiana
authors.affiliation: Fish Health and Environmental Laboratory, Brackishwater Aquaculture Development Center Situbondo, Indonesia.
authors.forename: Bambang
authors.initials: B
authors.lastname: Hanggono
mesh_terms: D000818:Animals; D017756:Aquaculture; D021862:Enterocytozoon; D005243:Feces / Q000382:microbiology; D033561:Penaeidae / Q000469:parasitology*; D016133:Polymerase Chain Reaction; D012758:Shellfish / Q000469:parasitology*
keywords: EHP; Enterocytozoon hepatopenaei; In situ hybridization; PCR; Shrimp disease; White feces syndrome