High infection rate of tick-borne protozoan and rickettsial pathogens of cattle in Malawi and the development of a multiplex PCR for Babesia and Theileria species identification
High infection rate of tick-borne protozoan and rickettsial pathogens of cattle in Malawi and the development of a multiplex PCR for Babesia and Theileria species identification
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DOI：
10.1016/j.actatropica.2022.106413
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发表时间：
2022-03-28
期刊：
影响因子：
2.7
通讯作者：
Nakao, Ryo
中科院分区：
文献类型：
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作者：
Chatanga, Elisha;Maganga, Emmanuel;Nakao, Ryo
马拉维估计有1,884,803头牛，当地的马拉维斑马品种占91.2%，而外来和杂交品种占剩余的8.8%。虽然壁虱和壁虱传播的疾病在马拉维很普遍，但还没有对感染牛的壁虱传播的无浆体科和梨形体虫进行分子研究。为了深入了解牛体壁虱传播病原体的现状，在马拉维中部和南部地区进行了一项分子调查。用热休克蛋白GroEL基因和18S rDNA分别对191头马拉维-弗里斯安牛、44头荷斯坦-弗里西亚牛和15头荷斯坦-弗里西亚/马拉维杂交牛进行了无浆体科和果浆体科筛选。设计了一种新的18S rDNA多重聚合酶链式反应方法，无需测序即可用于巴贝斯虫和泰勒氏菌的种类鉴定。总体而言，92.3%(n=177)的受检动物至少感染了一种TBP。无浆体科阳性率为57.6%(n=110)，梨形体阳性率为80.1%(n=153)。检出的无浆体科为牛无浆体占2.6%(n=5)，边缘无浆体占24.6%(n=47)，类无浆体占13.6%(n=26)。14.1%(n=27)，未鉴定的埃利希氏菌。16.2%(n=31)。检出的旋毛虫分别为巴贝斯虫2.6%(n=5)、变形泰勒氏菌73.8%(n=141)、微小泰勒氏菌33.0%(n=63)、牛磺酸泰勒氏菌12.6%(n=24)、绒毛泰勒氏菌53.4%(n=102)。混合感染率为79.6%(n=152)。这项研究表明马拉维牛的Tbps负担很高，这突显了需要构思新的方法来控制扁虱和Tbps，以改善动物健康和生产力。新开发的多重聚合酶链式反应分析将是一个有用的工具，特别是在资源有限的情况下，即无法获得测序和预期混合感染的情况下。
Malawi has an estimated cattle population of 1,884,803 heads, the indigenous Malawi zebu breed accounts for 91.2%, while the exotic and crossbred accounts for the remaining 8.8%. Although ticks and tick-borne diseases are widespread in Malawi, no molecular study has been conducted to investigate the tick-borne Anaplasmataceae and piroplasms infecting cattle. To provide an insight into the current status of tick-borne pathogens (TBPs) of cattle, a molecular survey was conducted in the central and southern regions of Malawi. A total of 191 cattle of which 132 were Malawi zebu, 44 were Holstein Friesian and 15 were Holstein-Friesian/ Malawi zebu crosses were screened for Anaplasmataceae and piroplasms using the heat shock protein groEL gene and 18S rDNA, respectively. A new 18S rDNA multiplex PCR assay was designed for Babesia and Theileria species identification without sequencing. Overall, 92.3% (n = 177) of the examined animals were infected with at least one TBP. Anaplasmataceae-positive rate was 57.6% (n = 110) while for piroplasms it was 80.1% (n = 153). The detected Anaplasmataceae were Anaplasma bovis 2.6% (n = 5), Anaplasma marginale 24.6% (n = 47), Anaplasma platys-like 13.6% (n = 26), uncharacterized Anaplasma sp. 14.1% (n = 27), and uncharacterized Ehrlichia sp. 16.2% (n = 31). The detected piroplasms were Babesia bigemina 2.6% (n = 5), Theileria mutans 73.8% (n = 141), Theileria parva 33.0% (n = 63), Theileria taurotragi 12.6% (n = 24), and Theileria velifera 53.4% (n = 102). Mixed infection rate was found in 79.6% (n = 152) of the samples analyzed. This study has shown a high burden of TBPs among cattle in Malawi which highlights the need to conceive new methods to control ticks and TBPs in order to improve animal health and productivity. The newly developed multiplex PCR assay would be a useful tool especially in resource limited settings where sequencing is not available and when mixed infections are expected.