Studies on the Pathogenic Agent of Infectious Hepatitis in Okayama Prefecture Ⅰ: Multiplication of Infectious Hepatitis Virus in the Chick Embryo

From the patients of infectious hepatitis in Okayama Prefecture, a kind of virus was isolated by Mnrakami et al. In the present paper, the author studied on the mode of multiplication of this virus in the chickembryo. The results are summarized as follows: 1) The susceptibility of the chickembryo to this virus can not be said a strong one. However, now that no more susceptible laboratory animal is found, the chickembryo seems to be the best one to establish the infection of this infectious hepatitis virus. The other supplemental experiments are also needed for determination of infection. 2) As compared with that of other viruses, the mode of multiplication of this hepatitis virus is a peculiar one showing the multiplication maxima 5 to 7 and 10 to 15 days after inoculation. However, the mode of multiplication and the characters of this virus show some variation with the passages in chickembryos. 3) The multiplication of the virus in the chickembryo is easilyy influenced by the age of the chickembryo, the life or death of the embryo, which is used as virus material, the cultivation period, the grade of dilution of the virus, the cultivation temperature and other various conditions, which make the direct quantitative determination of infection impossible. The infectious aspect of the virus in the chickembryo, however, can be inferred by pathologic findings in the mice re-infected.