Molecular Differentiation of Intact West Nile Virus Using a PMAxx™-Enabled Digital PCR Workflow

Area of Science:

• Virology
• Molecular Diagnostics
• Infectious Diseases

Background:

• Current West Nile virus (WNV) diagnosis uses nucleic acid amplification, which cannot differentiate between infectious and non-infectious viral particles.
• This limitation impacts accurate WNV diagnosis and epidemiological assessment.

Purpose of the Study:

• To evaluate a workflow combining PMAxx treatment and digital PCR for improved molecular discrimination of intact WNV particles.
• To assess the impact of PMAxx treatment on WNV RNA detection in patient samples.

Main Methods:

• Analysis of 55 patient samples (plasma and urine) from individuals with WNV fever or neuroinvasive disease.
• Comparison of WNV RNA detection with and without PMAxx treatment using digital PCR.

Main Results:

• PMAxx treatment significantly reduced detectable WNV RNA by a median of 1.0 Log copies/mL (p < 0.0001).
• Greater RNA reduction was observed in urine samples (1.8 Log copies/mL) compared to plasma (0.4 Log copies/mL).
• Significant WNV RNA reductions were noted in both WNV fever and neuroinvasive disease patient groups.

Conclusions:

• PMAxx treatment combined with digital PCR effectively discriminates between infectious and non-infectious WNV particles.
• This approach offers a valuable adjunct for improving WNV diagnostic interpretation and epidemiological studies, especially in samples with persistent RNA.