在中国新发现的一种羊的巴贝斯虫(Babesia)未定种

A Large Babesia sp New found from Affected Sheep in China

在中国甘肃某地自然感染发病绵羊的血液涂片中，观察到一种大型的巴贝斯虫（Ｂａｂｅｓｉａ）。虫体形态具多形性，有双梨籽形、单梨籽形、圆环形、棒状、不规则形、逗点形和三叶形。典型双梨籽形虫体的大小为１．８～２．５μｍ×０．９～１．８μｍ，平均（２．２１±０．１２）μｍ×（１．１７±０．１８）μｍ。个别红细胞中寄生有４个或８个虫体。该虫种特征性的形态是三叶形。它是相连的双梨籽形虫体两尖端的核质延伸（出芽），并生出原生质，发育成一个完整的梨籽形虫体，与母体共同排列形成三叶形的。该虫种可引起绵羊严重发病和死亡。本研究对自然感染发病羊的临床症状和死亡羊的病理变化进行了观察。该虫种的形态大小和致病力，与莫氏巴贝斯虫（Ｂ．ｍｏｔａｓｉ）和粗糙巴贝斯虫（Ｂ．ｃｒａｓｓａ）明显不同。

ALarge Babesia sp.was discovered in blood smears of naturally infected sheep in Gan su province P.R.China.The morphological properties are polymorphism,bipear shaped,monopear shaped,circular,rod shaped,irregular appearance,comma form,or three leaves form.The Babesia sp.with typical bipear appearance were measured from1.8 2.5μm×0.9 1.8μm with meaning (2 21±0 12)μm×(1 17±0 18)μm in size.There were4or8parasites within afew erythroc ytes of af fected sheep.The characteristic appearance of the parasite is three leave shaped which constructed from the combined bipear shaped parasite with its two pin ends nucleoplpasm being extended (budding)and the protoplasm produced.The clinacal symptoms of affected sheep and the pathological lesions of the dead animals were described.The morphological properties as well as the pathogenicity of the new found parasite obviously differ from thatof B motasi and/or B crassa