Detection and Quantification of the Oomycete Saprolegnia parasitica in Aquaculture Environments

Tiina Korkea-Aho*, Tom Wiklund, Christine Engblom, Anssi Vainikka, Satu Viljamaa-Dirks

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

4 Citations (Scopus)
81 Downloads (Pure)


Saprolegnia parasitica induces heavy mortality in aquaculture. The detection of S. parasitica is often time consuming and uncertain, making it difficult to manage the disease. We validated a previously published real-time quantitative PCR (qPCR) assay to confirm the presence of S. parasitica in fish and in water using environmental DNA (eDNA) quantification. Analytical sensitivity and specificity of the assay was assessed in silico, in vitro and the qPCR assay was compared with microbiological cultivation methods to detect and quantify S. parasitica in water samples from a controlled fish exposure experiment and from fish farms. Furthermore, we compared the use of an agar cultivation method and the qPCR assay to detect S. parasitica directly from mucus samples taken from the fish surface. The analytical sensitivity and specificity of the qPCR assay were high. The qPCR assay detected 100% of S. parasitica-positive water samples. In a field study, the qPCR assay and a microwell plate (MWP) enumeration method correlated significantly. Furthermore, the qPCR assay could be used to confirm the presence of S. parasitica in skin mucus. Thus, the qPCR assay could complement diagnostic methods in specifically detecting saprolegniosis in fish and used as a surveillance method for S. parasitica pathogen in aquaculture environments.

Original languageEnglish
Article number2186
Issue number11
Publication statusPublished - 2022
MoE publication typeA1 Journal article-refereed


  • eDNA detection
  • fish pathogen
  • oomycete
  • qPCR assay
  • Saprolegnia parasitica


Dive into the research topics of 'Detection and Quantification of the Oomycete Saprolegnia parasitica in Aquaculture Environments'. Together they form a unique fingerprint.

Cite this