Infection of herons and domestic fowls with Japanese encephalitis virus with specific reference to maternal antibody of hen (epidemiological study on Japanese encephalitis 26

Abstract

In order to ascertain whether black-crowned night herons (BCNH), white heron (Plumed Egrets (PE)) and domestic fowls are infected by JE virus and they serve as infection source ofJE, hemoagglutination inhibiting antibody and its 2·ME sensitive antibody in the sera of these birds were determined. Physico-chemical nature of fowl's antibody of JE produced by natural infection and their maternal antibody in the sera of chicks were examined. The results are briefly summarized as follows. 1) As to the herons captured in Tsudaka Town, two out of six adult night herons and three out of the four chicks showed positive HI reaction. On the other hand, HI reaction in the sera of two adult white herons and three chicks were negative. 2) As to the herons captured in Okayama City, twenty out of thirtytwo adult night herons and seven out of seventy white herons showed positive HI reaction in 1966 around the time when JE was prevalent in Okayama Prefecture. And six out of eleven night herons and one out of seven white herons showing positive HI reaction, responded positively to 2-ME sensitivity test. 3) The results indicate that white herons can be also infection source ofJE though less than in the case of night herons. 4) In the domestic fowls (white leghorn) kept at Takahashi District, eight out of twenty-seven fowls showed positive HI reaction. And six out of seven domestic fowls showing positive HI reaction responded positively to 2-ME sensitive reaction. 5) Transformation of JE antibody in the serum of hen from IgM to IgG was recognized. 6) Domestic chicken's sera having 1 : 640 of HI titer in the original serum and 1 : 320 of HI titer after 2-ME treatment were fractionated by gel filtration on Sephadex G-200 and the antibody activities present in the various fractions were determined. HI antibody activities occurred in both IgM and IgG classes of immunoglobulins. 7) Maternal HI antibodies reacting with JE virus were found in newly hatched domestic chickens from the eggs laid by hens with natural infection ofJE. And half life of HI antibodies in chicks was four days. 8) HI antibodies of JE in the serum of maternal immune-hens and chicken having maternal antibody were located in r-globulin fraction by starch block electrophoresis. 9) The results from 4) to 8) indicate the presence of natural infection ofJE in the domestic fowls. And domestic fowls can be infection source ofJE.</p