Rocky Mountain Spotted Fever, Panama
Figure 1. Histologic and immunohistochemical evaluation of heart tissue. A) Lymphohistiocytic inflammatory cell infiltrates in the myocardium (hematoxylin and eosin stain; original magnification ×25). B) Immunohistochemical detection of spotted fever group rickettsiae (red) in perivascular infiltrates of heart (immunoalkaline phosphatase with naphthol-fast red substrate and hematoxylin counterstain; original magnification ×250.