In vitro virucidal activity of nebulized citrate-complexed silver nanoparticles against equine herpesvirus-1 and murine norovirus.

The research article discusses the potential antiviral effectiveness of citrate-complexed silver nanoparticles (C-AgNP) against two types of viruses, equine herpesvirus-1 (EHV-1) and murine norovirus (MNV), through methods of instillation and nebulization.

Understanding the Viruses and Silver Nanoparticles

• The study focuses on two specific viruses, equine herpesvirus-1 (EHV-1) which often causes respiratory disorders in horses, and murine norovirus (MNV), which is used as a comparative for smaller non-enveloped viruses. The specific interest in using silver nanoparticles comes from their previously demonstrated bactericidal properties.
• Citrate-complexed silver nanoparticles (C-AgNP) are a combination of citrate ions and silver nanoparticles. These nanoparticles have been known to show antimicrobial features against various microorganisms.

Experimenting with Silver Nanoparticles against Viruses

• The researchers used increasing concentrations of C-AgNP for testing their effects on the viruses. These C-AgNPs were applied to the viruses either through instillation, where they were directly applied, or nebulization, where they were delivered in the form of mist.
• Titer determination, used to measure the quantity or concentration of a substance, was done using the TCID method in the research.

Results and Conclusions

• The treatment of EHV-1 with C-AgNP proved to be effective in the inactivation of enveloped EHV-1. The results showed losses of infectivity of three orders of magnitude, indicating a significant reduction.
• The non-enveloped MNV, however, stood up to the treatment much more resiliently. While 2000 ppm C-AgNP instillation did inactivate MNV, the nebulized form of C-AgNP led to no reduction in MNV titers.
• The promising results from the study led the researchers to conclude that the nebulized C-AgNP could potentially be a new method for antiviral therapy in horses. However, the researchers caution more investigation is necessary to understand the safety aspects and effective concentrations for in vivo usage, indicating their aim to move from the in vitro stage to live organism testing.