INVESTIGATION OF SPLENIC FUNCTIONS IN CANINE MONOCYTIC EHRLICHIOSIS

In order to determine the role of the spleen in the pathogenesis of ca nine monocytic ehrlichiosis (CME), the effect of splenectomy on the co urse of the acute phase of experimental was investigated. Intact and s plenectomized dogs, sere-negative for Ehrlichia canis antibodies, were infected with the Israeli strain of E. canis. Serology, clinical sign s and haematological parameters were recorded prior to infection, and over a period of 60 days post infection, and were compared between the intact and the splenectomized dogs. All dogs seroconverted for IFA E. canis antibodies by days 10 to 17 post infection. There did not appea r to be any difference in the day of appearance or in the titer of ant i-E canis IgG antibodies, between the splenectomized and intact groups throughout the course of the study. During the acute stage, food cons umption (percentage change) was significantly lower in the intact grou p compared to the splenectomized group (-66.3% and -25.38, respectivel y, p < 0.0001). During this period, significant higher body temperatur es were measured in the intact group (average of 39.76 degrees C vs. 3 8.96 degrees C, p < 0.0001). The haematocrit, red blood cell counts, h aemoglobin concentrations and platelet counts were significantly lower (p < 0.05) in the intact group when compared to the splenectomized gr oup during the whole course of the study, The clinical and the haemato logical findings in our study suggest that the disease process was mil der in the splenectomized dogs compared to the intact dogs. The result s of this study suggest that the spleen plays an important role in the pathogenesis of CME. Splenic inflammatory mediators and/or other sple nic substances, are proposed to play a key role in the pathogenesis of the disease. Our results further substantiate the involvement of immu ne mechanisms in the pathogenesis of CME. (C) 1998 Elsevier Science B. V.