Rapid Visual Detection of Feline Panleukopenia Virus Using Colorimetric Loop-Mediated Isothermal Amplification Assay

Area of Science:

• Veterinary Virology
• Molecular Diagnostics
• Infectious Disease Epidemiology

Background:

• Feline panleukopenia (FPV) is a severe, contagious disease threatening felid populations.
• Current diagnostic methods may not be suitable for rapid point-of-care testing (POCT) in field settings.
• Development of accessible diagnostic tools is crucial for disease management and conservation.

Purpose of the Study:

• To develop and validate a colorimetric loop-mediated isothermal amplification (LAMP) assay for FPV detection.
• To assess the assay's sensitivity, specificity, and applicability for POCT.

Main Methods:

• A colorimetric LAMP assay targeting the FPV VP2 gene was designed using cresol red indicator.
• Amplification was performed at 64°C for 40 minutes, with results visualized by color change (violet to yellow).
• Analytical sensitivity (limit of detection) and specificity (cross-reactivity) were determined, and clinical samples were tested.

Main Results:

• The assay demonstrated a limit of detection of 18.38 copies/µL (plasmid) and 10^1.62 TCID₅₀/mL (crude nucleic acids).
• No cross-reactivity was observed with other common feline pathogens, indicating good specificity.
• Testing of 153 clinical samples showed 40.52% positivity with 98.04% agreement compared to a commercial qPCR kit.

Conclusions:

• The developed colorimetric LAMP assay is a specific, sensitive, and simple visual method for FPV detection.
• This assay shows significant potential for field-based POCT applications in FPV diagnosis.
• While effective for FPV, the assay cannot differentiate from canine parvovirus (CPV) due to genetic similarities.