Viral load could be an important determinant for fomites based transmission of viral infections

Dhirendra P Singh1, Mahesh C Sahu2, Avinash Pagdhune3

  • 1Division of Toxicology, ICMR-National Institute of Occupational Health, Ahmedabad, Gujarat, India.

Abstract

Insights

Viral load on fomites, such as cardboard and stainless steel, is key to transmission. Higher viral loads increase the likelihood of pathogen detection on these surfaces, impacting infection spread.

Area of Science:

  • Virology
  • Infectious Disease Transmission
  • Surface Contamination

Background:

  • Fomites (inanimate objects) are recognized transmission routes for various infections, particularly respiratory viruses.
  • The quantity of infectious pathogen on fomites is a critical determinant of transmission efficiency.
  • Understanding viral load on common surfaces is essential for infection control strategies.

Purpose of the Study:

  • To investigate the viral load of a specific pathogen on commonly encountered fomite materials.
  • To determine the relationship between initial viral load and its persistence on different surface types.

Main Methods:

  • Viral samples were categorized by load (high, moderate, mild) based on cycle threshold (Ct) values.
  • Samples were applied to cardboard (absorbent) and stainless steel (non-absorbent) surfaces.
  • Post-exposure viral detection was performed using reverse transcription-polymerase chain reaction (RT-PCR) after 90 minutes.

Main Results:

  • A positive correlation was observed between initial viral load and the amount of virus detected on surfaces after the observation period.
  • Higher initial viral loads (lower Ct values) resulted in a greater probability of pathogen detection on both absorbent and non-absorbent surfaces.
  • The study quantified viral persistence on fomites based on initial pathogen concentration.

Conclusions:

  • Inanimate surfaces serve as significant reservoirs for viral transmission.
  • The concentration of virus on fomites is a critical factor influencing the risk of onward transmission.
  • Effective infection control requires consideration of viral load on fomites.

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