EXPERIMENTAL STUDIES ON THE IMMUNITY OF INFECTIOUS ECTROMELIA

Similarities in various characteristics between the ectromelia and the vaccinia viruses pointed out by Burnet and Fenner were also re-established by the authors experiments. However, it was revealed that, while mice immunized with live vaccinia virus resisted the intraperitoneal infection of the ectromelia (“Hampstead” strain), they showed same local lesions as the control animals when challenged with the ectromelia virus plantarly. On the other hand, mice surviving from the ectromelia infection could perfectly get rid of even the plantar reinfection.Similar relations concerning the injection route are observed also in the neutralization test. Thus, although the ectromelia-neutralizing ability of anti-vaccinia or anti-ectromelia mouse sera could be demonstrated when the virus-serum mixture was injected intraperitoneally into mice, it was not observed when the mixture was injected plantarly.The authors are tempted to assume the necessity that the systemic general infection and the local disease must be considered separately each other in the study of mouse ectromelia.An epidemic of ectromelia, from which a new virus strain, “Tama”, was isolated, was observed and investigated in a large group of mice purchased from an animal dealer in Tokyo.