Airborne micro-organisms: survival tests with four viruses

Abstract

Airborne virus particles of vaccinia, influenza, Venezuelan equine encephalomyelitis, and poliomyelitis have been tested for viable survival in the dark at controlled temperatures and relative humidity (R.H.) for up to 23 hr. after spraying.Viable survival at each R.H. level was better at lower temperature than at higher temperature. Poliomyelitis virus showed best survival at high R.H.; the other three viruses survived best at low R.H.

The inactivation of poliovirus in aerosols

“…These results confirm the reports of Hemmes et al (1960Hemmes et al ( , 1962 and Harper (1961Harper ( , 1963. They are also consistent with a tentative rule, deduced from published data on the survival of viruses in aerosols.…”

“…For poliovirus the kinetics of the decay in air have been described by Hemmes, Winkler & Kool (1960 and Harper (1961Harper ( , 1963. The mechanism, however, remained obscure.…”

Methods for the Assessment of Microbial Populations Recovered from Enclosed Aerosols

“…Fluorescent compounds such as sodium fluorescein (Wolfe, 1961;Miller & Artenstein, 1967) and Rhodamine B (Songer, 1967) or a radioisotope such as [32P]orthophosphate (Harper, 1961 ;Harstad, 1965;Benbough, 1971) can be criticized on the following grounds. A substance of relatively small molecular weight will distribute evenly among the aerosol particles but, particularly with sparse microbial populations, all aerosol particles do not contain microbes; microbecontaining particles will have different physical properties from particles containing tracer alone and this may affect the ratio of tracer to microbial particles in samples collected from the cloud.…”

“…A substance of relatively small molecular weight will distribute evenly among the aerosol particles but, particularly with sparse microbial populations, all aerosol particles do not contain microbes; microbecontaining particles will have different physical properties from particles containing tracer alone and this may affect the ratio of tracer to microbial particles in samples collected from the cloud. Another and more serious criticism of sodium fluorescein is that it may be toxic to aerosolized bacteria and viruses, particularly in the presence of simulated solar radiation (Dorsey, Berendt & Neff, 1970;Berendt & Dorsey, 1971 Anderson & Cox (1967), the preferred radiotracer technique involves the use of microbes with incorporated radioisotope such as %S (Miller, Scherff, Piepoli & Idoine, 1961), s2P (Harper & Morton, 1952) or l4C (Anderson, 1966). Alternatively, a labelled suspension of killed tracer microbes is added to the test microbe suspension (Harper, Hood & Morton, 1958;Miller et al 1961 ;Anderson, 1966).…”

“…Another and more serious criticism of sodium fluorescein is that it may be toxic to aerosolized bacteria and viruses, particularly in the presence of simulated solar radiation (Dorsey, Berendt & Neff, 1970;Berendt & Dorsey, 1971 Anderson & Cox (1967), the preferred radiotracer technique involves the use of microbes with incorporated radioisotope such as %S (Miller, Scherff, Piepoli & Idoine, 1961), s2P (Harper & Morton, 1952) or l4C (Anderson, 1966). Alternatively, a labelled suspension of killed tracer microbes is added to the test microbe suspension (Harper, Hood & Morton, 1958;Miller et al 1961 ;Anderson, 1966). Radiotracer techniques cannot by applied to the assay of diluted microbial suspensions because the excessive amounts of radioactivity required would damage the organisms.…”