Clinical Investigation and Molecular Diagnosis of Microsporidian Enterocytozoon hepatopenaei (EHP) in Shrimps from Selangor, Malaysia

In recent years, shrimp aquaculture production in Southeast Asia countries was highly infected by, microsporidian parasite, EHP. Recently, shrimps from farms located in Selangor were encountering growth retardation and it highly concerned us to carry out a clinical investigation in both farms (Location A and B). EHP infected P. monodon samples were collected from both locations. A total of 43 shrimp samples were collected and diagnosed via PCR using the 18S rRNA gene. Environmental parameters were found relatively higher than the advised values. It indicates that the farms are highly infected and toxic which had led to growth retardation and mortality. However, no significant differences were observed (except water temperatures) between the locations. The phylogenetic analysis expressed EHP detected from Malaysia formed in one clade and all the reference sequences clustered based on geographical continents (Asian-Latin America). Minimum-spanning network analysis shows that Malaysia samples Location A are genetically related with other Asian EHP samples even though the total positive rate of EHP infection was lower. However, samples from Location B were not clustered within the EHP clade and shows the highest genetic variance within Malaysia and among Asian samples. This preliminary investigation results confirmed the incidence of EHP outbreak in Malaysia.