An efficient recovery method for enteric viral particles from agricultural soils

Area of Science:

• Environmental Virology
• Food Safety
• Molecular Diagnostics

Background:

• Enteric viruses are primary causes of global gastroenteritis and hepatitis outbreaks.
• Understanding viral environmental persistence is crucial for infection control.
• Efficient recovery methods for soil-borne viruses are needed.

Purpose of the Study:

• To develop an effective procedure for recovering infectious enteric viruses from agricultural soils.
• To optimize viral recovery and minimize PCR inhibitors for accurate detection.
• To evaluate recovery efficiency across different soil types and viral agents.

Main Methods:

• Soil samples (black earth, loamy, sandy) were inoculated with murine norovirus (MNV) and feline calicivirus (FCV).
• Five different buffers and three commercial kits were tested for viral RNA extraction.
• Modified Eagle's medium buffer combined with Dynabeads nucleic acid extraction demonstrated superior performance.

Main Results:

• The optimized method achieved high recovery rates for infectious MNV (54.3%–56.9%) across soil types.
• Feline calicivirus (FCV) recovery varied by soil type, with lower percentages in loamy (15.6%) and sandy (17.7%) soils.
• The study identified an effective buffer-kit combination for preserving viral infectivity and removing PCR inhibitors.

Conclusions:

• A modified Eagle's medium buffer and Dynabeads nucleic acid extraction kit provide an efficient method for enteric virus recovery from soils.
• Accurate detection of enteric viruses in environmental samples necessitates robust recovery procedures and internal process controls.
• Implementing internal process controls, like MNV inoculation, is vital to prevent false negatives in molecular detection.