Identifies Spirochetes and other bacteria such as H. pylori and two causative agents of cat scratch disease, Bartonella henselae and Afipia felis. Warthin-Starry Stain relies on the ability of certain bacteria to bind silver ions from solution. Subsequent addition of a reducing agent then converts this bound silver to visible metallic silver. In the Warthin-Starry stain, tissue is sensitized prior to application of the silver complex. An aqueous silver nitrate solution combined with the reducing agent hydroquinone is applied and a silver diamine complex is generated.