Unexpectedly, we detected EHP in 4 out of 9 samples of frozen
Artemia biomass (Fig. 2, lane 9, a representative sample). From
EHP-positive Artemia biomass, its 18S rRNA gene was amplified
and sequenced, and the 1.1 kb fragment was 99.9% identical
(different in 2 nucleotides) to that of EHP from Vietnam, suggesting
the EHP present in Artemia biomass may have originated from SE
AE. hepatopenaei (EHP)-infected Penaeus stylirostris were
collected from Brunei in 2006. EHP-infected P. vannamei were
collected in shrimp ponds from Vietnam in 2014 and 2015. A population
of P. vannamei was sent from Thailand to our laboratory at
University of Arizona in 2014 for a quarantine purpose, these
shrimp were later diagnosed with EHP infection by histology, their
hepatopancreas, feces and tank water were sampled for PCR
analyses.