Cross R F, Smith C K, Redman D R
Can J Comp Med. 1971 Jan;35(1):12-7.
Naturally occurring Trypanosoma theileri infection was studied in two cattle herds. Herd A was a dairy herd of approximately 250. Herd B was an isolated herd of 32 and contained both dairy and beef breeds. Blood samples were collected from all animals in Herd A during July and August on two successive years. Samples were collected from Herd B at monthly intervals. Total leukocyte and differential counts packed cell volume determinations, and trypanosome cultures were made on each sample. Infection was detected in all age groups between seven months and fifteen years but it was rare in calves. Infected animals were not consistently positive for trypanosomes on consecutive blood cultures and there was considerable variation between infected individuals. Positive cultures were usually obtained from some animals while others were positive intermittently. No correlation was found between trypanosome isolations and the season of the year.A correlation was found between trypanosome isolation and lymphocytosis. Of the 920 blood samples examined, approximately one in every five trypanosome positive samples had lymphocyte levels in the Bendixen positive range. Approximately one in every twenty trypanosome negative samples had lymphocyte numbers in the Bendixen positive range. Evidence indicated that trypanosome isolation from animals with lymphocytosis was not caused by increased numbers of infected buffy coat cells in the inoculum cultured. Eight calves were inoculated intravenously with trypanosome-infected blood. Lymphocyte numbers increased an average of 3549 per cumm above pre-inoculation levels in seven and remained essentially unchanged in one. Prior to inoculation with infective blood, two of the calves were intravenously inoculated with trypanosome-infected blood that had been frozen and thawed to kill the trypanosomes contained in it. Neither developed lymphocytosis following this inoculation. No clinical disease problems which could be attributed to trypanosome infection were found.
对两个牛群中的自然发生的泰勒锥虫感染情况进行了研究。A群是一个约有250头奶牛的牛群。B群是一个有32头牛的隔离牛群，包括奶牛和肉牛品种。在连续两年的7月和8月从A群的所有动物采集血样。每月从B群采集样本。对每个样本进行全白细胞计数、分类计数、红细胞压积测定和锥虫培养。在7个月至15岁的所有年龄组中均检测到感染，但在犊牛中很少见。感染动物在连续血培养中锥虫并非始终呈阳性，且感染个体之间存在相当大的差异。阳性培养物通常从一些动物中获得，而其他动物则间歇性呈阳性。未发现锥虫分离与一年中的季节之间存在相关性。发现锥虫分离与淋巴细胞增多之间存在相关性。在检查的920份血样中，每五份锥虫阳性样本中约有一份淋巴细胞水平处于本迪克斯森阳性范围内。每二十份锥虫阴性样本中约有一份淋巴细胞数量处于本迪克斯森阳性范围内。有证据表明，从淋巴细胞增多的动物中分离出锥虫并非由接种物培养中感染的血沉棕黄层细胞数量增加所致。给8头犊牛静脉注射锥虫感染的血液。7头犊牛的淋巴细胞数量平均比接种前水平每立方毫米增加3549个，1头犊牛基本保持不变。在接种感染性血液之前，给其中2头犊牛静脉注射了经冷冻和解冻以杀死其中所含锥虫的锥虫感染血液。接种后这两头犊牛均未出现淋巴细胞增多。未发现可归因于锥虫感染的临床疾病问题。
