Figure 1

Skin lesions in lambs naturally infected with A. phagocytophilum. a) Skin biopsy with an attached tick (arrow) and ulceration of epidermis. Inflammatory cell infiltrates are present in dermis and subcutis underneath the tick bite. [Haematoxylin and eosin. Bar = 300 μm.]

b) Photomicrograph of dermis. Thrombi (t) are present in lymphatics and venules, and a focal necrosis is observed in the wall of an artery (a). Infiltration of leukocytes, moderate oedema and proliferation of fibrous tissue is found in dermis. [Haematoxylin and eosin. Bar = 100 μm.]

c) Photomicrograph of dermis. A large thrombus is occluding the lumen of a vein (arrows). Infiltration of neutrophils, macrophages and lymphocytes are present in dermis. [Haematoxylin and eosin. Bar = 50 μm.]