Constraints to estimating the prevalence of trypanosome infections in East African zebu cattle.
Constraints to estimating the prevalence of trypanosome infections in East African zebu cattle.
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DOI：
10.1186/1756-3305-3-82
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发表时间：
2010-09-06
影响因子：
3.2
通讯作者：
Welburn SC
中科院分区：
文献类型：
--
作者：
Cox AP;Tosas O;Tilley A;Picozzi K;Coleman P;Hide G;Welburn SC
在东非，动物锥虫病是由许多采采蝇传播的原生动物寄生虫引起的，包括间日锥虫、T。congolense和T.布鲁塞公司（T. B.布氏杆菌和人畜共患传染性T. B. Rhodesiense），可能在家畜和野生动物中共同传播。这些寄生虫在动物种群中的准确种属特异性流行率测量因个体宿主内锥虫混合感染、寄生虫密度低和难以进行实地研究而变得复杂。许多基于聚合酶链反应（PCR）的诊断工具可用于检测和量化动物感染。这些对于评估动物宿主中感染的贡献以及人畜共患锥虫物种对人类构成的风险非常重要。新的DNA捕获矩阵简化了大规模现场PCR分析，但很少有研究探讨这些技术对流行率估计的影响。Whatman FTA矩阵已被评估使用随机样本的35个村瘤牛自然暴露于锥虫感染的人口。使用通用锥虫特异性PCR，患病率进行了系统评价。从单个FTA卡中采集的多个PCR样本表明，FTA卡的单次穿孔不足以确认个体动物的感染性状态，因为寄生虫DNA在卡上分布不均匀。在宿主中寄生虫密度较低时，这种随机抽样效应导致基于单冲PCR检测的流行率被低估。重复检测增加了所有锥虫属的估计患病率。从9.7%上升到86%。通过重复检测，在这些当地村牛中检测到非常高的致病性锥虫患病率：T。布氏锥虫（34.3%）、T. congolense（42.9%）和T.间日疟占22.9%。这些结果表明，尽管Whatman FTA卡和基于PCR的特异性检测工具很方便，但土著非洲瘤牛的寄生虫血症长期较低，难以确定真正的患病率。虽然本研究专门适用于FTA卡，但使用含有低寄生虫密度的血液样本的其他方法也会产生类似的效果。例如，使用血膜显微术或从液体样品进行PCR检测，其中在所需数量的视场或PCR反应中检测寄生虫或DNA分子的概率小于1。
In East Africa, animal trypanosomiasis is caused by many tsetse transmitted protozoan parasites including Trypanosoma vivax, T. congolense and subspecies of T. brucei s.l. (T. b. brucei and zoonotic human infective T. b. rhodesiense) that may co-circulate in domestic and wild animals. Accurate species-specific prevalence measurements of these parasites in animal populations are complicated by mixed infections of trypanosomes within individual hosts, low parasite densities and difficulties in conducting field studies. Many Polymerase Chain Reaction (PCR) based diagnostic tools are available to characterise and quantify infection in animals. These are important for assessing the contribution of infections in animal reservoirs and the risk posed to humans from zoonotic trypanosome species. New matrices for DNA capture have simplified large scale field PCR analyses but few studies have examined the impact of these techniques on prevalence estimations. The Whatman FTA matrix has been evaluated using a random sample of 35 village zebu cattle from a population naturally exposed to trypanosome infection. Using a generic trypanosome-specific PCR, prevalence was systematically evaluated. Multiple PCR samples taken from single FTA cards demonstrated that a single punch from an FTA card is not sufficient to confirm the infectivity status of an individual animal as parasite DNA is unevenly distributed across the card. At low parasite densities in the host, this stochastic sampling effect results in underestimation of prevalence based on single punch PCR testing. Repeated testing increased the estimated prevalence of all Trypanosoma spp. from 9.7% to 86%. Using repeat testing, a very high prevalence of pathogenic trypanosomes was detected in these local village cattle: T. brucei (34.3%), T. congolense (42.9%) and T. vivax (22.9%). These results show that, despite the convenience of Whatman FTA cards and specific PCR based detection tools, the chronically low parasitaemias in indigenous African zebu cattle make it difficult to establish true prevalence. Although this study specifically applies to FTA cards, a similar effect would be experienced with other approaches using blood samples containing low parasite densities. For example, using blood film microscopy or PCR detection from liquid samples where the probability of detecting a parasite or DNA molecule, in the required number of fields of view or PCR reaction, is less than one.
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影响因子：
2.7
作者：
Koffi, M.;Solano, P.;Jamonneau, V.
通讯作者：
Jamonneau, V.
影响因子：
3.2
作者：
Adams, E. R.;Hamilton, P. B.;Gibson, W. C.
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影响因子：
2.4
作者：
ARTAMA, WT;AGEY, MW;DONELSON, JE
通讯作者：
DONELSON, JE
影响因子：
1.5
作者：
MacLeod, A;Turner, CMR;Tait, A
通讯作者：
Tait, A
DOI：
10.4269/ajtmh.2007.76.1132
发表时间：
2007-06-01
影响因子：
3.3
作者：
Morrison, Liam J.;McCormack, Gillian;MacLeod, Annette
通讯作者：
MacLeod, Annette