1.Complete data pertaining to studies on Japanese B encephalitis on Okinawa during the years 1945 through 1949 is presented.
2.The occurrence of the disease in natives is examined in the light of population trends and accuracy of diagnosis. A total of 401 cases, with a case fatality of 35 per cent, have been observed during these five years. During the same period twenty-one cases have occurred in Americans, with a case fatality of 28 per cent.
3.Laboratory aspects of the disease are presented with particular emphasis on time of development and persistence of antibodies. The role of “inapparent” infections is reviewed. Definite evidence is presented to validate the occurrence of such infections.
4.The serologic response to vaccination is demonstrated. The number of cases in vaccinated Americans is not sufficient to permit deductions as to the protective value. The response to recall vaccination is greater than the initial response. The use of vaccine with the subsequent recall serological response as a survey tool is outlined.
5.The serological pattern in various animals suggests that practically all mammals are or have been infected. Potential arthropod vectors are reviewed, and the thus-far futile efforts to prove vector are summated.
6.Areas for future study are delineated.
Present address: Army Medical Department Research and Graduate School, Washington 12, D. C.
Present address: Graduate School of Public Health, University of Pittsburgh, Pittsburgh 13, Pennsylvania.
The senior authors were responsible for the planning and the administrative aspects of the field and laboratory work recorded herein. However, as will be apparent from even a brief perusal of the report, it represents a composite of data obtained by many individuals during the various years. An attempt has been made to give specific credit in the body of the paper and the names of those who have contributed most extensively are listed alphabetically as co-authors.
It is desired to express particular indebtedness and thanks to Lt. Col. W. S. Smith, Director of the Public Health Department of the Military Government Section of the Ryukyus (1947–1948), to Major Ellis Arkus and Capt. E. F. Weglarz of the Military Government Staff, to Col. J. B. Dismukes, Commanding Officer of the 37th Station Hospital, to Col. Thair Rich, Surgeon, Ryukyus Command, and to Doctors Chokei Ogimi and Jyunkei Kinjyo of the Okinawa Public Health Section.
Virus and Rickettsial Section, 406th Medical General Laboratory.
Member of 1947 field unit of the Commission on Virus and Rickettsial Diseases. On leave of absence from the Rockefeller Institute for Medical Research, New York, N. Y.
37th Station Hospital.
3rd Medical General Laboratory.
Member of 1947 field unit of the Commission on Virus and Rickettsial Diseases. On leave of absence from the Division of Medicine of the University of California and the Viral and Rickettsial Laboratory of the California State Department of Public Health.
The Hooper Foundation for Medical Research.
Member of 1947 field unit of the Commission on Virus and Rickettsial Diseases. On leave of absence from the Department of Invertebrate Zoology and Entomology, University Of Utah, Salt Lake City, Utah.