[Skip to Content]
[Skip to Content Landing]
Other Articles
June 9, 1945


JAMA. 1945;128(6):443. doi:10.1001/jama.1945.02860230047015

In a survey for the presence of type specific antibodies in the human and animal populations of the St. Louis area, Margaret Smith and her associates1 of Washington University School of Medicine learned that few persons who had come into St. Louis County since the 1937 epidemic of encephalitis showed neutralizing antibodies specific for this virus. A large percentage of the local domestic fowls approximately 1 year of age, however, were carriers of this specific antibody. This led to the belief that some insect vector that does not bite man was mainly responsible for the spread of St. Louis encephalitis virus among domestic fowls.

Blattner2 had shown that certain ticks (Dermacentor variabilis) become infected with this virus and transmit it by bite to susceptible animals. Infected ticks transmit the virus to their offspring for innumerable generations. Smith therefore turned her attention to the common chick mite, which belongs