Inactivation of Lassa, Marburg, and Ebola viruses by gamma irradiation

Abstract

Because of the cumbersome conditions experienced in a maximum containment laboratory, methods for inactivating highly pathogenic viruses were investigated. The infectivity of Lassa, Marburg and Ebola viruses was inactivated without altering the immunological activity after radiation with 60Co .gamma.-rays. At 4.degree. C, Lassa virus was the most difficult to inactivate with a rate of 5.3 .times. 10-6 log 50% tissue culture infective dose[TCID50]/rad of 60Co radiation, as compared with 6.8 .times. 10-6 log TCID50/rad for Ebola virus and 8.4 .times. 10-6 log TCID50/rad for Marburg virus. Experimental inactivation curves and curves giving the total radiation needed to inactivate a given concentration of any of the 3 viruses, are presented. This method of inactivation was superior to UV light or .beta.-propiolactone inactivation and is now routinely used for preparation of material for protein-chemistry studies or for preparation of immunological reagents.