Figure 2.

Immunohistochemistry for Anaplasma phagocytophilum on skin tissue in lambs naturally infected with A. phagocytophilum. a) Intracellular Anaplasma organisms (arrows) are present in the lumen of a small vessel. Vasculitis characterised by thickened wall and infiltration of numerous leukocytes is present in this vessel. A few bacteria are observed in the vessel wall, whereas more Anaplasma organisms are found in leukocytes in dermis. [Msp2 (P44) immunostain, original magnification, ×1000]. b) Numerous Anaplasma organisms (arrows) are found in neutrophils and macrophages infiltrating the dermis. [Msp2 (P44) immunostain, original magnification, ×1000]