Studies of six new viruses in tumor-bearing mice.

Guaroa virus inhibited or destroyed ascites tumors (Ehrlich or Sarcoma 180) of Swiss white mice when inoculated intraperitoneally from 1 to 6 days after tumor in jection. Thirty of 79 virus-treated mice survived 30 days after injection of Ehrlich ascites cells without accumulation of ascites, whereas all but two of 73 controls died with a mean survival time of 15 days. With Sarcoma 180 ascites, eleven of 30 treated mice survived 30 days without ascites, whereas all but one of 20 controls died in an av erage of 17 days. No deaths were attributable to the Guaroa virus. Germistan and Oriboca viruses inhibited the ascites tumors but were so virulent that the treated mice died sooner than did the controls. Sindbis, Chickungunya, and Middleberg viruses had no detectable oncolytic effect. Limited studies of virus distribution in blood, brain, and tumor are recorded. None of the viruses significantly inhibited the growth of subcu taneous Ehrlich or Sarcoma 180 tumors.