Relapsing Fever in California

Attempts to Transmit Spirochaetes of California Relapsing Fever to Human Subjects by Means of the Bite of the Vector, Ornithodoros Hermsi Wheeler

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  • Pacific Institute of Tropical Medicine within the George Williams Hooper Foundation for Medical Research, San Francisco, California
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The rôle of ticks in the transmission of relapsing fever in California was first suspected by Dr. LeRoy Briggs in 1922 in his report dealing with two cases which occurred near Polaris, Nevada county, California (2). Since living conditions under which the disease was contracted did not indicate the presence of lice, and since specimens of ticks of the genus, Ornithodoros, had been collected in the state of Nevada not far from Polaris, it was believed that the vector in California would prove to be an Argasine tick, particularly a member of the genus Ornithodoros.

With the decided increase in the number of cases of relapsing fever reported during 1931 the California State Department of Public Health with the cooperation of the Hooper Foundation for Medical Research and the Department of Entomology and Parasitology, University of California, a comprehensive investigation was undertaken in the late summer of that year and repeated in the summer of 1932 and continued in 1933 at the three infected areas existing at that time, namely, Packer Lake, Sierra county, Lake Tahoe, Placer and Eldorado counties and Big Bear Lake, San Bernardino county.