Absence of myelofibrosis in dogs with myelosuppression induced by Ehrlichia canis infection.

Bone marrow (BM) pathology was assessed in 10 dogs with Ehrlichia canis-induced aplastic pancytopenia. BM core biopsy sections were stained with haematoxylin and eosin and with haematoxylin/van Gieson and Gordon and Sweets' reticulin stain for the detection of collagen and reticulin fibres, respectively. Iron stores were assessed by Perls' Prussian blue staining. There was no significant deposition of collagen or reticulin in any sample, but in seven dogs the BM was depleted of haemosiderin. These findings suggest that myelofibrosis does not play a significant role in the development of BM failure in canine monocytic ehrlichiosis and that iron deficiency may exacerbate the anaemia in the myelosuppressive phase of the disease.