ISOLATION AND CHARACTERIZATION OF BORRELIA-BURGDORFERI FROM BLOOD OF A BIRD CAPTURED IN THE SAINT-CROIX RIVER VALLEY

Field investigations were conducted to further evaluate the. role of b irds in the maintenance and dissemination of Borrelia burgdorferi. Blo od specimens were taken from 39 passerine birds of 17 species captured during June 1991 at the Saint Croix National Riverway in Wisconsin, a nd one isolate, WI91-23, was cultured from an adult song sparrow (Melo spiza melodia). This isolate was shown to be infectious for Peromyscus leucopus and Mesocricetus auratus (golden hamster). Isolate WI91-23 w as confirmed as B. burgdorferi by immunofluorescence assay by using sp ecies-specific anti-OspA monoclonal antibodies H3TS and H5332 and anti -OspB antibody H5TS. Isolate WI91-23 was compared with Borrelia anseri na Es, Borrelia hermsii MAN-1, and other B. burgdorferi strains (ATCC 53210, CT-1, and Catharus fuscescens [veery] liver 10293). Pulsed-fiel d gel electrophoresis of in situ-lysed spirochetes revealed that the D NA plasmid profile of WI91-23 was most similar to those of plasmids fr om B. burgdorferi and most different from those of plasmids from B. an serina and B. hermsii. Sodium dodecyl sulfate-polyacrylamide gel elect rophoresis analysis indicated that the protein profile of WI91-23 was like that of other B. burgdorferi strains studied, with dominant prote ins corresponding to OspA and OspB, and that it differed from the prot ein profiles of B. anserina and B. hermsii. These findings indicate th at passerine birds may serve as reservoirs for B. burgdorferi.