Mouse hepatitis virusに関する研究 (第1報)

Abstract

During the past 6 years 6 strains of hepatotropic virus of mice have been described. Some of them appear to be related to each other serologically.The present mouse hepatitis virus (Buescher's EHF-120) was encountered during attempts to establish the agents of hemorrhagic fever in mice by serial blind passage of viscera.The purpose of this communication is to give some account of the disease produced in mice by this virus and to describe its general properties.Acute hepatitis was regularly reproducible in mice by the intraperitoneal injection of liver suspensions from dead or moribund mice. Infected mice showed a ruffled coat, “hunched” posture, and fine tremors before death. The incubation period was usually about 30 hours and the desth was occured between 2nd and 3rd day. The urine was staining some times the coat in the perineal region, but there was no external indication of jaundice.On post-mortem examination the most striking abnormality was found in the liver. Liver was pale yellow and mottled with petechial hemorrhages. In other organs there was no obvious lesion.The distribution of the virus in several viscera after intraperitoneal injection was determined and the high concentration was proved in liver and brain. The virus was also found in the spleen, kidney, lung, , intestine and blood of the infected mice at the death or moribund stage.Other inoculation procedures were also examined. The mice were infected by intracerebral, intranasal, subcutaneous, intravenous, per os, and food pad inoculation. Gross pathological changes in the liver were seen in all dead mice, irrespective of the route of inoculation, suggesting a hepatotropic character of this virus.The virus survies heating at 60°C for 30 minutes and exposure to ultraviolet-irradiation at the distance of 9cm from the lamp for 5 minutes. The activity of the infected liver in 50 per cent glycerol was retained on storage in the refrigerator for intervals up to 2 months. The filtrate of the liver suspension through Seitz EK filter was also infectious.Attempts were made to infect rats, guinea-pigs, hamster, and rabbits by intraperitoneal or intravenous inoculation of infected mouse liver extract, but no symptoms or lesions were produced in these species.The chorioallantois of 9 to 13 day old chick embryos was inoculated with infected mouse liver. After 48 to 72 hours' incubation at 36°C discrete white foci were noticed on these membranes at least at the beginning of this experiment. On continued passage, the numder of foci produced decreased progressively. Although the virus was detectable in the chickembryo liver and on the membranes by mice inoculation in the 1st to 4th passge, it became impossible afterwards.