EFFECT OF DICHLOROTETRAFLUOROETHANE ON THE INFECTIVITY OF VIRUSES AND RICKETTSIAE SENSITIVE TO TRICHLOROTRIFLUOROETHANE
ARMY BIOLOGICAL LABS FREDERICK MD
Pagination or Media Count:
In contrast to the true viruses, agents of the psittacosis group and most of the rickettsiae are markedly inactivated by treatment with the trichlorotrifluoroethane Freon-113. Tests indicate that these organisms that are sensitive to Freon 113 are not inactivated by comparable treatment with dichlorotetrafluoroethane Freon-114. Infectivity titers of suspensions of 5 representative rickettsiae were reduced 1 to 4 logs by emulsification with Freon-113, whereas similar treatment with Freon-114 caused no significant titer change for 4 of the rickettsiae and a one log decrease for the most sensitive one. Titers of suspensions of psittacosis virus and murine pneumonitis virus, which were reduced 1 to 2 logs by extraction with Freon-113, were not affected by treatment with Freon-114. A possible explanation of these differences is that Freon-113 is a much better lipid solvent than Freon-114. Difference in solvent power andor density of these fluorocarbons is reflected in their relative effectiveness in clarifying yolk-sac suspensions of the organisms tested Freon-114 removed 50 of the protein and 15 of the lipid in a single extraction compared pared with 50 of the protein and 78 of the lipid by Freon-113. To remove larger percentages of protein and lipid, multiple extractions with Freon 114 are feasible. The infectivity of psittacosis virus in a yolk-embryo suspension was not reduced by three successive extractions with Freon-114.