SURVIVAL OF ENTERIC VIRUSES ON ENVIRONMENTAL FOMITES

The survival of human enteric viruses on several porous (paper acid co tton cloth) and nonporous (aluminum, china, glazed tile, latex, and po lystyrene) environmental surfaces has been evaluated. Viruses persiste d for extended periods on several types of materials commonly found in institutions and domestic environments. The stability of the viruses was generally influenced by environmental factors such as relative hum idity (RH), temperature, and the type of surface contaminated. Overall , hepatitis A virus (HAV) and human rotavirus (HRV) were more resistan t to inactivation than enteric adenovirus (ADV) and poliovirus (PV). T he resistance to the desiccation step appears to be of major significa nce in determining the survival of a virus dried on fomites. ADV and P V showed a pronounced decrease in titer at this stage, whereas HAV and HRV displayed little decay at the desiccation step. HAV and HRV persi stence was not affected by the presence of fecal material. On nonporou s surfaces, PV and ADV persisted better in the presence of feces. Howe ver, on porous fomites the presence of fecal material had a negative i nfluence on the survival of PV and ADV. Except for HRV, greater virus survival was observed at 4 degrees than at 20 degrees C. PV and HAV su rvival was enhanced at high RH; the survival of the latter was enhance d at least for nonporous materials. When dried on porous materials, HR V also exhibited greater persistence at high RH. The survival of ADV w as not affected by RH. The validity of using bacteriophages of Bactero ides fragilis as indicators of human viruses dried on fomites was eval uated. B. fragilis phages persisted consistently longer than PV and AD V and sometimes survived as long as HAV and HRV.