IMMUNOHISTOCHEMICAL IDENTIFICATION OF COWDRIA-RUMINANTIUM IN FORMALIN-FIXED TISSUE-SECTIONS FROM MICE, SHEEP, CATTLE AND GOATS

An immunohistochemical staining technique in which a monospecific seru m was used against the major antigenic protein-1 (MAP-1) of Cowdria ru minantium, was evaluated for the detection of C. ruminantium in formal in-fixed tissues of experimentally infected mice and field cases of he artwater in sheep, cattle and goats. Mice were infected with the mouse -pathogenic stocks: Mara, Kwanyanga, Welgevonden, Nonile, Vosloo, Kumm , Mali and Omatjenne. In all these cases and in the naturally infected cattle, sheep and goats, Cowdria colonies were identified as clearly- defined, brown-staining rickettsial colonies within the cytoplasm of e ndothelial cells. No positive staining was observed in the control gro up. This technique was shown to be reliable for detecting infection wi th C. ruminantium in the formalin-fixed tissues of mice and domestic r uminants.