Differentiation between Cyprinid herpesvirus type-3 lineages using duplex PCR.

Area of Science:

• Veterinary Virology
• Aquatic Animal Health
• Molecular Diagnostics

Background:

• Cyprinid herpesvirus type-3 (CyHV3) causes significant disease outbreaks in carp (Cyprinus carpio).
• Previous studies using limited gene sequences showed high similarity among CyHV3 isolates.
• Full-length genome sequencing revealed two distinct genetic lineages: U/I and J.

Purpose of the Study:

• To develop a rapid molecular diagnostic tool for distinguishing CyHV3 genetic lineages without DNA sequencing.
• To analyze the genetic diversity of CyHV3 isolates from European carp populations.

Main Methods:

• Targeted two molecular markers with known genetic variations between CyHV3 lineages.
• Developed and validated a duplex PCR assay for simultaneous detection of CyHV3-U/I and CyHV3-J.
• Tested the assay on 42 carp samples collected from France, The Netherlands, and Poland (2001-2008).

Main Results:

• The duplex PCR assay successfully differentiated between CyHV3-U/I and CyHV3-J genotypes.
• Identified both U/I and J genotypes, along with a third, intermediate genotype for one marker.
• The assay is effective for samples with moderate to high viral loads.

Conclusions:

• A novel duplex PCR assay provides an efficient method for CyHV3 genotyping.
• The findings reveal genetic diversity within CyHV3 populations, including intermediate forms.
• This tool will enhance understanding of CyHV3 epidemiology, distribution, and evolutionary dynamics.