Cryopreservation of an avian spirochete strain in liquid nitrogen.
Serum samples were obtained from chickens with clinical signs of spirochaetosis, thought to be caused by Borrelia anserina. Sterilized glycerol (at a dilution of 1:2, v/v) or dimethyl sulfoxide (DMSO; 1:10 v/v) were added to the sera before storage in liquid nitrogen. After 15 months storage, infectivity tests were conducted in chickens. Compared with glycerol, DMSO was a superior cryoprotectant. All chickens inoculated with the DMSO sera showed spirochaetaemia within 48 h after inoculation.