Öz
Leptospirosis is a zoonotic disease common in the world and in our country. The disease affects people as well as cattle, sheep, cats, dogs, and other domestic animals. In the disease, which causes serious health problems in humans and significant economic losses in animals, some living things spread the disease without showing any clinical symptoms, although they are causative agents in their bodies. For this reason, it is important to constantly investigate the disease in different animal species. There are many studies on the disease in humans and animals worldwide. In Turkey, most of the studies are serological, but immunohistochemical studies were also conducted in different animal species. Although there have been studies on cattle and sheep abortions with immunohistochemical methods in the Erzurum region, where the study samples were provided for the diagnosis of the disease, no study was found in dogs. This study was aimed to determine the presence and localization of Leptospira interrogans (L. İnterrogans) antigens in testicular tissue samples of naturally infected dogs with immunohistochemical methods. In the study, 30 dog testicular tissue samples collected without looking for macroscopic lesions were examined using the immunohistochemical method. As a result of the examination, 26.66% (8) L. İnterrogans antigens were detected in canine testicular tissue samples. The research results showed that leptospirosis is an important health problem in dogs.