Persistence of Venezuelan Equine Encephalitis Virus on Exposure to Three Types of Materials

As many were made acutely aware during the initial period of the COVID 19 pandemic in the spring of 2020, there is the potential for viral infection through fomites, inanimate objects can be contaminated with pathogens. Although transmission through fomites was shown to be only a minor component of the SARS-CoV-2 pandemic, this mode of transmission can be more prevalent with other viruses. Understanding the persistence of viruses in the environment by assessing virus viability in different types of samples, such as liquid, aerosol, and surfaces, can be important in formulating infection control both for naturally occurring outbreaks as well as in the case of an intentional release of a biothreat agent. Alphaviruses are enveloped viruses with RNA genomes and include viruses of importance to human and animal health as well as ones that have been identified as potential biothreat agents. There are only limited studies on the persistence of alphaviruses. In one study Chikungunia virus was shown to be infective for over 60 weeks when stored refrigerated in sterile distilled water in the dark. Likewise Venezuelan equine encephalitis virus (VEEV) was stable in distilled water at 4 deg C with essentially no decrease over 21 days, while when samples were kept at room temperature (21 deg C) there was a steady decrease in viability over the three weeks. Another study examined the persistence of VEEV and other viruses of concern when dried onto solid surfaces. This work showed that the VEEV was more resistant to deactivation than either Lassa virus or Ebola virus, with 90 percent reduction in viral load on a glass surface at 98 hours; the loss of VEEV viability was similar on glass, metal, and rubber surfaces.