Immunohistochemical detection of leptospiral antigens in cases of naturally occurring abortions in sheep

This study was carried out to determine the leptospiral antigens in naturally occurring 108 abort sheep fetuses. To determine the antigen localizations in tissue sections (kidney, liver, lung and spleen) of each fetus were stained with immunoperoxidase (IP) technique and then were examined under light microscope. The results of this study showed that 19 (17%) out of 108 fetuses were positive for the presence of leptospiral antigens. In the 19 positive cases, leptospiral antigens were found in lung (n = 10; 9%), liver (n = 7; 6%), kidney (n = 12; 11%) and spleen (n = 2; 2%) samples. Microscopic studies demonstrated that leptospiral antigens were located in the cytoplasm of macrophages in interalveolar and interlobular septum of the lung; in the cytoplasm of macrophages in the portal regions and hepatocytes of the liver; in the cytoplasm of epithelial cells of renal pelvis, in the cytoplasm of epithelial cells of cortical and medullar tubules, and macrophages of intertubular region in the kidney. In the spleen, antigens were detected in the cytoplasm of macrophages throughout the parenchymal tissue. In conclusion, the results of this study demonstrate that leptospirosis could be a major disease causing abortions in sheep.