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This article discusses a study on the detection of Neoparamoeba perurans, a parasite that causes amoebic gill disease (AGD) in salmon. The study compares the use of DNA-based and RNA-based assays for detecting N. perurans in seawater samples. The researchers found that the RNA-based assay was more sensitive and reliable than the DNA-based assay, detecting N. perurans even at low concentrations. The study suggests that targeting intracellular RNA may provide a more accurate measure of amoeba abundance. Further research is needed to determine if RNA-based quantification of N. perurans can be used as an early indicator of AGD. [Extracted from the article]

ABSTRACT The genetic composition of greenlip abalone (Haliotis laevigata) from Point Cook in Port Phillip Bay was examined prior to the aggregation of individuals from this site for ranching. The [...]

Amoebic gill disease (AGD), caused by Neoparamoeba perurans, is a major health challenge for Atlantic salmon aquaculture globally. While freshwater bathing for 2 hr is effective in reducing infection severity, there is need for more rapid and lower cost alternatives. To this end, a combination of sodium percarbonate (SPC) in freshwater was examined for its treatment efficacy. Initial in vitro studies showed a reduction in amoeba viability when exposed for 30 min to freshwater containing >500 mg/L SPC. Subsequently, AGD‐affected salmon were bathed for 30 min in 16°C freshwater containing 100, 500 or 1,000 mg/L SPC, or for 2 hr in 16°C freshwater to mimic industry practice. Treatment at the highest SPC concentration caused extensive gill damage and substantial mortality. Neither occurred to a significant extent at lower SPC concentrations. Gill pathology of surviving fish 10 days post‐treatment (dpt) was comparable to or more severe than pre‐treatment, and significantly (p <.001) more severe than in 2 hr freshwater bathed fish. N. perurans DNA was confirmed by qPCR in all treatment groups at 10 dpt. The data indicate that a 30‐min exposure to SPC in freshwater is not a suitable alternative to existing freshwater treatment of AGD. [ABSTRACT FROM AUTHOR]