Transovarial transmission efficiency of Babesia bovis tick stages acquired by Rhipicephalus (Boophilus) microplus during acute infection
Transovarial transmission efficiency of Babesia bovis tick stages acquired by Rhipicephalus (Boophilus) microplus during acute infection
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DOI：
10.1128/jcm.01757-06
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发表时间：
2007-02-01
影响因子：
9.4
通讯作者：
Knowles, Donald P.
中科院分区：
文献类型：
--
作者：
Howell, Jeanne M.;Ueti, Massaro W.;Knowles, Donald P.
牛巴贝斯虫（Babesia bovis）是一种重新出现的对美国牛的威胁的原生动物寄生虫，由嗜牛亚属（Boophilus）的成年雌性蜱虫获得，并作为着床期经卵巢传播给发育中的幼虫后代。孢子子在幼虫体内发育，并在幼虫取食牛宿主时传播。本研究评估了在急性寄生虫病牛的摄食后，微头鼻虫（Boophilus）感染牛B. bovis的效率。测定了实验感染牛的血液、获得性饲养的母牛的血淋巴和幼虫中的寄生虫水平。急性寄生虫病牛血中寄生虫水平与获得性饲养后成年雌蜱血淋巴细胞水平呈正相关；然而，雌虫的卵母细胞水平与幼虫后代的感染率之间没有关系。获得性饲养的微乳杆菌雌虫产生的幼虫后代感染率为12% ~ 48%。重要的是，显微镜和聚合酶链反应显示，从极低水平的着细胞感染的充满活力的雌性中产生的幼虫感染率为22%至30%，并在传播喂养过程中传播牛b。这些数据表明，虽然血淋巴感染可能无法检测到，但传播到幼虫后代的水平确保传播到牛宿主。
The protozoan parasite Babesia bovis, a reemerging threat to U.S. cattle, is acquired by adult female ticks of the subgenus Boophilus and is transovarially transmitted as the kinete stage to developing larval offspring. Sporozoites develop within larvae and are transmitted during larval feeding on a bovine host. This study evaluated the efficiency of B. bovis infection within Rhipicephalus (Boophilus) microplus following acquisition feeding on acutely parasitemic cattle. Parasite levels were quantified in blood from experimentally infected cattle and within hemolymph and larvae derived from acquisition-fed female B. microplus. There was a positive correlation between blood parasite levels in acutely parasitemic cattle and kinete levels in the hemolymph of adult female Boophilus ticks following acquisition feeding; however, there was no relationship between kinete levels in females and infection rates of larval progeny. Boophilus microplus females that acquisition fed produced larval progeny with infection rates of 12% to 48%. Importantly, larvae derived from replete females with very low levels of kinete infection, as demonstrated by microscopy and PCR, had infection rates of 22% to 30% and transmitted B. bovis during transmission feeding. These data demonstrate that although hemolymph infection may be undetectable, transmission to larval progeny occurs at a level which ensures transmission to the bovine host.