Evaluation of blood and bone marrow in selected canine vector-borne diseases

Abstract

BackgroundBone marrow (BM) is a major hematopoietic organ that can harbour a variety of vector-borne pathogens; however, knowledge of BM pathological changes in dogs infected with vector-borne pathogens is limited. Thus, the aim of the present study was to assess the pathological changes in canine BM associated with natural infections by four vector-borne pathogens, as well as to determine the relationships between such changes and abnormalities of the peripheral blood.MethodsCytological disorders and pathological changes of the BM of 83 dogs naturally-infected with one or more of four vector-borne pathogens (i.e., Anaplasma platys, Leishmania infantum, Babesia vogeli and Hepatozoon canis) were evaluated and compared with the corresponding hematological findings.ResultsDysgranulopoiesis and dysmegakaryocytopoiesis were the most frequently observed BM abnormalities in infected dogs. Erythroid suppression, and lymphocytic, monocytic and macrophage hyperplasia were also observed. Interestingly, associations between suppression and hyperplasia of specific cell lines in the marrow and corresponding changes in numbers of circulating peripheral blood cells were not observed.ConclusionsInfections with one or more of the vector-borne pathogens examined in this study should be considered as differential diagnoses for secondary dysmyelopoiesis.

Laboratory tests for diagnosing and monitoring canine leishmaniasis

“…The hematologic profile of leishmaniotic dogs may be complemented by bone marrow cytology, which may be highly diagnostic just by the microscopic identification of amastigotes in macrophages. In addition, the quantitative assessment of the frequency of infected macrophages in a bone marrow smear may allow differentiation between an infected and a sick dog, as the parasite load and the magnitude of cytologic alterations are generally more prominent in dogs with clinical signs, although some histologic studies demonstrated that parasite density can be high despite few clinical signs .…”

“…27 Neutrophilia, due to a systemic inflammatory response, may be present and particularly prominent in cases with ulcerative cutaneous lesions and secondary bacterial infection. 27,28 Conversely, quantitative or qualitative morphologic changes in the other leukocyte populations are less common, although lymphopenia, lymphocytosis, or eosinophilia are occasionally described [28][29][30] Amastigotes are rarely documented in circulating neutrophils, lymphocytes, and monocytes of infected dogs (< 0.5% of cases). 29,31 As the percentage of infected cells is so low, a microscopic search in peripheral blood smears is generally not rewarding.…”

Evaluation of blood and bone marrow in selected canine vector-borne diseases

“…engulfing of various BM cells by megakaryocytes [40], was also frequently observed in this study. Emperipolesis increases in various disorders, including multiple myeloma, carcinoma, lymphoma [41], platelet disorders [42] and serious hemorrhage [43], however the pathophysiological importance of emperipolesisis is yet to be fully understood and its significance is uncertain [44,45]. Indeed, this event may be linked to the effects of interleukin-6 (IL-6), which alters the process of megakaryocyte maturation, thus altering thrombocytopoiesis [45].…”

“…Emperipolesis increases in various disorders, including multiple myeloma, carcinoma, lymphoma [41], platelet disorders [42] and serious hemorrhage [43], however the pathophysiological importance of emperipolesisis is yet to be fully understood and its significance is uncertain [44,45]. Indeed, this event may be linked to the effects of interleukin-6 (IL-6), which alters the process of megakaryocyte maturation, thus altering thrombocytopoiesis [45]. To our knowledge, prior to the present study, emperipolesis had only been described in dogs infected by L. infantum [8] and A. platys [39]; we describe, for the first time, emperipolesis in dogs infected or co-infected by H. canis.…”

Bartonella henselae infection in a dog with recalcitrant ineffective erythropoiesis

“…Another study found that Anaplasma platys, a tick‐transmitted, obligate intra‐platelet rickettsial pathogen, can infect megakaryocytes and promegakaryocytes in dogs . Anemia, thrombocytopenia, and pancytopenia are well‐recognized hematopoietic or immune‐mediated abnormalities in dogs infected with Ehrlichia canis . Among other hematological abnormalities, dysgranulopoiesis and dysmegakaryocytopoiesis were the most frequently observed bone marrow abnormalities in dogs infected with Anaplasma platys, Leishmania infantum, Babesia vogeli , and Hepatozoon canis .…”