Using molecular data for epidemiological inference: assessing the prevalence of Trypanosoma brucei rhodesiense in tsetse in Serengeti, Tanzania.
Using molecular data for epidemiological inference: assessing the prevalence of Trypanosoma brucei rhodesiense in tsetse in Serengeti, Tanzania.
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DOI：
10.1371/journal.pntd.0001501
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发表时间：
2012-01
影响因子：
3.8
通讯作者：
Welburn S
中科院分区：
文献类型：
--
作者：
Auty HK;Picozzi K;Malele I;Torr SJ;Cleaveland S;Welburn S
测量采采蝇种群中可传播布氏锥虫的患病率对于了解传播动态、评估人类疾病风险和监测时空趋势以及控制干预措施的影响至关重要。虽然是一个重要的流行病学变量，但识别携带传染性感染的苍蝇是困难的，挑战包括低流行率，同一苍蝇中存在其他锥虫物种，以及同时检测未成熟的非传染性感染。诊断测试来衡量T。B.采蝇中的罗得西亚蜱的应用和解释并不一致，研究之间的差异表明，这一数值的估计并不一致，甚至在一个数量级内。三种方法被用来估计传播性布氏锥虫s.l.的患病率。和T. B. Rhodesiense在Glossina swynnertoni和G.在坦桑尼亚塞伦盖蒂国家公园的pallidipes：（i）解剖/显微镜检查;（ii）对感染的采采蝇中肠的PCR;和（iii）从数学模型的推断。使用解剖/显微镜检查，布鲁塞公司为0%（95%CI 0-0.085）。swynnertoni和0%（0-0.18）G. pallidipes;使用PCR检测T. B.罗德西亚蜱的平均回收率分别为0.010%（0-0.054）和0.0089%（0-0.059），模型推断分别为0.0064%和0.00085%。解剖/显微镜检查的零患病率结果（考虑到其他方法的结果，可能确实大于零）在该技术中并不罕见，通常归因于灵敏度差。其他技术的应用证实了T。brucei，表明零流行率结果可归因于样本量不足（尽管检查了6000只采采蝇）。鉴于通过解剖/显微镜获得有意义的结果所需的样本量过高，基于PCR的方法提供了目前评估采采蝇锥虫患病率的最佳选择，但将PCR结果与传播性相关的不一致性突出表明需要共识方法来产生有意义的和可比的数据。人类非洲锥虫病是一种由采采蝇媒介携带的致命疾病。评估采采蝇携带人类感染性锥虫的比例对于评估人类疾病风险和了解疾病传播动力学非常重要。然而，识别携带传染性感染的苍蝇是困难的，因为在同一苍蝇中可能存在其他锥虫物种，并且同时检测不传染的未成熟感染。我们使用了三种方法来估计携带人类感染性锥虫的苍蝇的比例：苍蝇的解剖和显微镜检查，直接在苍蝇中观察锥虫;通过显微镜观察锥虫的苍蝇中肠的PCR;以及使用疾病传播的数学模型进行理论分析。所有这三种方法都发现流行率极低。鉴于患病率低，解剖/显微镜检查需要过大的样本量，因此基于PCR的方法可能最有价值。然而，PCR数据的解释并不简单;虽然PCR鉴定携带病原体遗传物质的苍蝇，但它不能直接鉴定具有传染性感染的苍蝇。这项研究强调了需要一个共识的方法，对PCR数据的分析和解释，以产生可靠的和可比的措施，苍蝇的比例，携带可传播的人类感染性锥虫。
Measuring the prevalence of transmissible Trypanosoma brucei rhodesiense in tsetse populations is essential for understanding transmission dynamics, assessing human disease risk and monitoring spatio-temporal trends and the impact of control interventions. Although an important epidemiological variable, identifying flies which carry transmissible infections is difficult, with challenges including low prevalence, presence of other trypanosome species in the same fly, and concurrent detection of immature non-transmissible infections. Diagnostic tests to measure the prevalence of T. b. rhodesiense in tsetse are applied and interpreted inconsistently, and discrepancies between studies suggest this value is not consistently estimated even to within an order of magnitude. Three approaches were used to estimate the prevalence of transmissible Trypanosoma brucei s.l. and T. b. rhodesiense in Glossina swynnertoni and G. pallidipes in Serengeti National Park, Tanzania: (i) dissection/microscopy; (ii) PCR on infected tsetse midguts; and (iii) inference from a mathematical model. Using dissection/microscopy the prevalence of transmissible T. brucei s.l. was 0% (95% CI 0–0.085) for G. swynnertoni and 0% (0–0.18) G. pallidipes; using PCR the prevalence of transmissible T. b. rhodesiense was 0.010% (0–0.054) and 0.0089% (0–0.059) respectively, and by model inference 0.0064% and 0.00085% respectively. The zero prevalence result by dissection/microscopy (likely really greater than zero given the results of other approaches) is not unusual by this technique, often ascribed to poor sensitivity. The application of additional techniques confirmed the very low prevalence of T. brucei suggesting the zero prevalence result was attributable to insufficient sample size (despite examination of 6000 tsetse). Given the prohibitively high sample sizes required to obtain meaningful results by dissection/microscopy, PCR-based approaches offer the current best option for assessing trypanosome prevalence in tsetse but inconsistencies in relating PCR results to transmissibility highlight the need for a consensus approach to generate meaningful and comparable data. Human African trypanosomiasis is a fatal disease that is carried by a tsetse vector. Assessing the proportion of tsetse which carries human-infective trypanosomes is important in assessing human disease risk and understanding disease transmission dynamics. However, identifying flies which carry transmissible infections is difficult, due to potential presence of other trypanosome species in the same fly, and concurrent detection of immature infections which are not transmissible. We used three methods to estimate the proportion of flies carrying human-infective trypanosomes: dissection and microscopic examination of flies to visualise trypanosomes directly in the fly; PCR of fly midguts in which trypanosomes were observed by microscopy; and theoretical analysis using a mathematical model of disease transmission. All three methods found the prevalence to be extremely low. Given the low prevalence, dissection/microscopy requires prohibitively large sample sizes and therefore PCR-based approaches are likely to be of most value. However, interpretation of PCR data is not straightforward; whilst PCR identifies flies carrying pathogen genetic material it does not directly identify flies with transmissible infections. This study highlights the need for a consensus approach on the analysis and interpretation of PCR data to generate reliable and comparable measures of the proportion of flies which carry transmissible human-infective trypanosomes.
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影响因子：
2.7
作者：
Adams, E. R.;Malele, I. I.;Gibson, W. C.
通讯作者：
Gibson, W. C.
影响因子：
1.9
作者：
HARGROVE, JW;LANGLEY, PA
通讯作者：
LANGLEY, PA
影响因子：
1.9
作者：
Barclay, HJ;Hargrove, JW
通讯作者：
Hargrove, JW
DOI：
10.1016/0035-9203(85)90187-7
发表时间：
1985-01-01
影响因子：
2.2
作者：
GIBSON, WC;WELLDE, BT
通讯作者：
WELLDE, BT
影响因子：
1.9
作者：
HARGROVE, JW;PACKER, MJ
通讯作者：
PACKER, MJ