[Effect of a mixed viral infection on the development of neoplasms induced by oncogenic viruses]

Data are presented concerning the stimulating effect of vaccinia and herpes simplex type 2 viruses on the development of leukemia in BALB/C, C57BL/6, and AKR mice. Mixed infection with PAB-49 and Marek disease virus of brown leghorn chickens was shown to increase the frequency of lymphomas development.