Kettner F, Reyers F, Miller D
Department of Companion Animal Clinical Studies, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa.
J S Afr Vet Assoc. 2003 Sep;74(3):63-8. doi: 10.4102/jsava.v74i3.512.
Canine babesiosis is a common cause of thrombocytopaenia but there are few formal studies that have investigated this haematological finding in dogs. Thrombocyte counts from full blood counts were retrospectively analysed for the years 1996-2002. Thrombocyte counts and mean platelet volumes of dogs with babesiosis were compared with those of dogs, seen over the same period of time, that did not have babesiosis. There were 1162 cases in the Babesiosis group and 10 808 in the Non-babesiosis group. A frequency distribution of the thrombocyte counts showed a trimodal distribution in the Non-babesiosis group compared to a bimodal distribution in the Babesiosis group, with a strong positive skewness. The modes for the frequency distributions were 10, 40, 300 and 10, 35 x 10(9)/l thrombocytes, respectively. The median thrombocyte count in the Babesiosis group was 14 x 10(9)/l and 282 x 10(9)/l in the Non-babesiosis group. There was a statistically significant difference in the median thrombocyte count between the Babesiosis group and the Non-babesiosis group. In the Babesiosis group, 99% of the thrombocyte counts were below the lower reference range value (250 x 10(9)/l) and 62% of thrombocyte counts were below 25 x 10(9)/l. The mean platelet volume (11.1 fl) for the Babesiosis group was greater than the reference range (6-10 fl) and significantly larger than in the Non-babesiosis group (median 9.7 fl). Thrombocyte counts greater than 110 and 250 x 10(9)/l had a predictive value that the dog was not suffering from babesiosis of 99.3% and 99.8%, respectively. There was a statistically significant difference between the thrombocyte counts of dogs with babesiosis when grouped by parasitaemia scores. The mechanisms of the thrombocytopaenia are not fully understood, and multiple mechanisms, including concomitant thrombocytopaenia-inducing diseases such as ehrlichiosis, probably result in this haematological finding. Babesiosis in the South African canine population is associated with thrombocytopaenia in nearly all patients and is severe in the majority of them. In the absence of thrombocytopaenia, babesiosis is an unlikely diagnosis.
犬巴贝斯虫病是血小板减少的常见原因，但很少有正式研究调查犬类的这一血液学表现。对1996年至2002年全血细胞计数中的血小板计数进行了回顾性分析。将患有巴贝斯虫病的犬的血小板计数和平均血小板体积与同期未患巴贝斯虫病的犬进行比较。巴贝斯虫病组有1162例，非巴贝斯虫病组有10808例。血小板计数的频率分布显示，非巴贝斯虫病组呈三峰分布，而巴贝斯虫病组呈双峰分布，且有很强的正偏态。频率分布的众数分别为10、40、300和10、35×10⁹/L血小板。巴贝斯虫病组的血小板计数中位数为14×10⁹/L，非巴贝斯虫病组为282×10⁹/L。巴贝斯虫病组和非巴贝斯虫病组的血小板计数中位数存在统计学显著差异。在巴贝斯虫病组中，99%的血小板计数低于参考范围下限值（250×10⁹/L），62%的血小板计数低于25×10⁹/L。巴贝斯虫病组的平均血小板体积（11.1飞升）大于参考范围（6 - 10飞升），且显著大于非巴贝斯虫病组（中位数9.7飞升）。血小板计数大于110和250×10⁹/L时，预测犬未患巴贝斯虫病的准确率分别为99.3%和99.8%。按寄生虫血症评分分组时，患有巴贝斯虫病的犬的血小板计数存在统计学显著差异。血小板减少的机制尚未完全了解，多种机制，包括同时存在的如埃立克体病等导致血小板减少的疾病，可能导致了这一血液学表现。南非犬类群体中的巴贝斯虫病几乎在所有患者中都与血小板减少有关，且大多数患者的血小板减少情况较为严重。若无血小板减少，巴贝斯虫病不太可能被诊断。
