Fig. 4

Histological examination of ticks located in the subcutaneous tissue of a red fox from Germany. a Well-preserved tick of category 1 in the subcutaneous fat tissue (marked by asterisk) (H&E). b The hypostome of the tick from a at a higher magnification. The hypostome is surrounded by a mixture of inflammatory cells and a fibrous capsule (H&E). c A deformed tick of category 2 in the subcutaneous tissue above the cutaneous muscle (panniculus carnosus) (CM). Three appendages (AP) are visible, but due to high deformation of the tick not assignable to legs or palpi (H&E). d Magnification of alloscutum (AS), the inner part of the tick and the surrounding inflammation of the tick from c. The inner part of the tick contains of cell debris (marked by asterisk) without any cellular structure (H&E). e The broken parts of exoskeleton of category 3 tick (H&E). f Infiltration of broken exoskeleton with inflammatory cells consisting of histiocytes, eosinophils and multinuclear giant cells (H&E). Scale-bars: a, c, e, 500 µm; b, d, f, 100 µm