AIM To provide useful information based on the macropathology, histopathology and immunohistochemical investigation in the spleens of dogs with Babesia rossi infection. METHODS AND RESULTS Control spleens were collected from four healthy dogs euthanized for welfare reasons. Nine dogs that died naturally because of a mono-infection with Babesia rossi were selected for the diseased group. One haematoxylin and eosin stained section of splenic tissue from each of the infected and control dogs was examined under the light microscope. Immunohistochemical markers were applied to characterise different immunocyte populations. The application of analytic software enabled semi-quantitative comparison of leukocyte subpopulations. Routine splenic histopathology revealed diffuse intermingling of white and red pulp from infected dogs with a clear loss of distinction between these zones. Immunohistochemistry revealed an increase in the proportion of tissue resident and bone marrow origin macrophages in the infected spleens. Apart from a few remnant lymphocytes within the peri-arteriolar lymphatic sheaths and follicles, the majority of the immunocytes redistributed to the red pulp, supporting the observation of white and red pulp intermingling. CONCLUSION The majority of our findings are in agreement with histomorphological descriptions of the spleen in a variety of non-canid mammalian hosts with lethal malaria or babesiosis.

中文翻译：

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致死性犬巴贝西虫病的脾脏病理学由罗氏杆菌引起。

目的基于宏观病理学，组织病理学和免疫组化研究方法，对罗氏杆菌感染犬的脾脏提供有用的信息。方法和结果从四只健康的安乐死的狗中收集了对照脾脏，出于福利考虑。选择了九只因罗氏杆菌（Babesia rossi）单次感染而自然死亡的狗作为患病组。在光学显微镜下检查每个受感染和对照犬的脾组织的苏木精和曙红染色切片。免疫组织化学标记用于表征不同的免疫细胞群。分析软件的应用使得能够对白细胞亚群进行半定量比较。常规脾脏组织病理学显示，受感染狗的白色和红色牙髓弥漫性混合，这些区域之间的区别明显消失。免疫组织化学显示感染的脾脏中组织固有和骨髓来源的巨噬细胞比例增加。除了小动脉周围淋巴鞘和滤泡内的少量残留淋巴细胞外，大多数免疫细胞都重新分布到红髓，支持观察白浆和红浆混合。结论我们的大多数发现与各种非致死性疟疾或轻度疟原虫的非宿主哺乳动物脾脏的组织形态学描述一致。免疫组织化学显示感染的脾脏中组织固有和骨髓来源的巨噬细胞比例增加。除了小动脉周围淋巴鞘和滤泡内的少量残留淋巴细胞外，大多数免疫细胞都重新分布到红髓，支持观察白浆和红浆混合。结论我们的大多数发现与各种非致死性疟疾或轻度疟原虫的非宿主哺乳动物脾脏的组织形态学描述一致。免疫组织化学显示感染的脾脏中组织固有和骨髓来源的巨噬细胞比例增加。除了小动脉周围淋巴鞘和滤泡内的少量残留淋巴细胞外，大多数免疫细胞都重新分布到红髓，支持观察白浆和红浆混合。结论我们的大多数发现与各种非致死性疟疾或轻度疟原虫的非宿主哺乳动物脾脏的组织形态学描述一致。