Growth of Louse-Borne Relapsing Fever Spirochetes in Chick Embryo

Abstract

It is well known that important biological differences exist between the tick-borne and louse-borne relapsing fever spirochetes. With the former, infection can readily be produced in a large variety of laboratory animals which together with the tick, serve as means of keeping the strain in the laboratory. On the other hand, few animals were found to be susceptible to the louse-borne type, and the lice cannot be used to maintain the spirochetes. Although Meleney1 was able to produce infection and relapses in squirrels and chipmunks with a Chinese louse-borne strain of relapsing fever spirochetes, splenectomy of these animals has to be resorted to in order to assure complete success. It is, therefore, of more than academic interest to determine if the louse-borne strains can also be grown and passed in the embryonic chick as is possible for the tick-borne spirochetes,2, 3, 4 and the preliminary results are herewith communicated.Blood samples were obtained from 7 patients with louse-borne relapsing fever5, 6...