Molecular and Pathological Investigation of Spirochaetosis in a Commercial Layer Flock - Case Report

The present investigation was carried out of a natural outbreak of spirochaetosis in 46 weeks old layer birds. The most striking post-mortem lesion was an enlarged mottled spleen. Necrotic foci with thickening of the capillary walls in the spleen, severe fatty changes in the liver, and degenerative tubular epithelial cells with casts and lymphocytic infiltration in the kidney were evident histopathologically. PCR amplification of the extracted DNA from spleen tissue indicated 725 and 750 bp amplicon specific for the flagellin gene (flaB) of Borrelia anserina by respective primers. The strain causing the disease was phylogenetically closely related to the Iranian and Brazilian strains of B. anserina. This report describes the genetic characterization and phylogenetic analysis of B. anserina from a field outbreak of spirochaetosis in layer chickens from India.