Development of a Real-Time PCR Assay for Noninvasive Detection of Miamiensis avidus in Olive Flounder Aquaculture

Jin-Young Kim ¹, Su-Mi Shin ¹, Se Ryun Kwon ²

⁰Department of Aqualife Medicine, Chonnam National University, Yeosu, Republic of Korea.

Journal of Fish Diseases +

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April 23, 2025

View abstract on PubMed

Summary

A new real-time PCR assay accurately detects Miamiensis avidus, a parasite causing significant losses in olive flounder aquaculture. This sensitive, noninvasive method aids disease management in fish farms.

Area Of Science

Aquatic Animal Health
Molecular Diagnostics
Parasitology

Background

Miamiensis avidus (syn. Philasterides dicentrarchi) causes high mortality and economic losses in olive flounder (Paralichthys olivaceus) aquaculture.
Effective detection methods are crucial for managing this parasite in aquaculture settings.

Purpose Of The Study

To develop and validate a sensitive, specific, and noninvasive real-time PCR assay for detecting and quantifying Miamiensis avidus in seawater.
To assess the prevalence of M. avidus in aquaculture environments.

Main Methods

Development of a real-time PCR assay targeting the cytochrome c oxidase subunit I (cox1) gene of M. avidus.
Standardization using plasmids, determination of amplification efficiency, and specificity testing against related marine ciliates.
Quantification of M. avidus in seawater samples from infected fish tanks and water sources.

Main Results

The assay demonstrated high linearity (R² = 0.9985) and amplification efficiency (96.26%).
The assay specifically detected M. avidus (cox1 genotypes 1-4) with no cross-reactivity, detecting as few as 2 cells/L.
High M. avidus density (57.81 cells/10 L) was found in tanks with infected olive flounder.

Conclusions

The developed real-time PCR assay is a sensitive, specific, and noninvasive tool for M. avidus detection and quantification.
This method facilitates improved disease prevention and management strategies in olive flounder aquaculture.
Noninvasive seawater sampling offers higher sensitivity compared to traditional tissue sampling.

Keywords:

Miamiensis avidus Philasterides dicentrarchi cytochrome c oxidase subunit I (cox1) noninvasive real‐time PCR