Mycobacterial antigen detection by immunohistochemistry in goat paratuberculosis.

An immunohistochemical method (PAP) for a microscopic diagnosis of paratuberculosis in goats is described as an alternative method to the Ziehl-Neelsen technique. Mycobacterial antigens are only found in enteric and mesenteric lymph node lesions. This method is the most sensible, particularly in cases in which there are no paratuberculosis lesions and the Ziehl-Neelsen technique shows no acid-fast bacilli (AFB).