The trusted provider of veterinary information since 1955
Photomicrograph of L interrogans in a microscopic agglutination test. The characteristic hooked ends (described as resembling "question marks" or "interrogation points," which give the species its name) are visible in nonagglutinated bacteria. Dark-field microscopy; original magnification, low power (4X).
Courtesy of the Department of Pathobiology, University of Guelph.