Diagnosing Polyparasitism in a High-Prevalence Setting in Beira, Mozambique: Detection of Intestinal Parasites in Fecal Samples by Microscopy and Real-Time PCR.
Diagnosing Polyparasitism in a High-Prevalence Setting in Beira, Mozambique: Detection of Intestinal Parasites in Fecal Samples by Microscopy and Real-Time PCR.
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DOI：
10.1371/journal.pntd.0005310
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发表时间：
2017-01
影响因子：
3.8
通讯作者：
van Lieshout L
中科院分区：
文献类型：
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作者：
Meurs L;Polderman AM;Vinkeles Melchers NV;Brienen EA;Verweij JJ;Groosjohan B;Mendes F;Mechendura M;Hepp DH;Langenberg MC;Edelenbosch R;Polman K;van Lieshout L
许多不同的肠道寄生虫物种可以在同一人群中共存。然而，经典的诊断工具只能确定一组特定的肠道寄生虫物种。因此，一个或两个测试不足以提供一个给定的人口感染寄生虫物种的全貌。本研究调查了莫桑比克贝拉的肠道寄生虫感染情况，即Inhamudima的非正式定居点。比较了五种经典的显微镜技术和实时PCR检测广谱寄生虫的诊断准确性。进行了一项基于人口的横断面调查。每名参与者（n = 303）的粪便样本进行了检查，直接涂片，甲醛乙醚浓度（FEC），加藤涂片，Baermann方法，共培养和实时PCR。我们发现，几乎所有的人（96%）都至少有一个寄生虫，几乎一半（49%）的人有三个或更多的寄生虫。值得注意的是，粪类圆线虫感染广泛，患病率为48%，钩虫属。流行率高于美洲钩虫（25%对15%），钩虫种，通常认为流行于东非。在显微镜技术中，FEC能够检测到最广泛的寄生虫物种。然而，FEC也错过了相当数量的感染，特别是S。stercoralis、曼氏血吸虫（Schistosoma mansoni）和G.好吧PCR在检测寄生虫种类的灵敏度和范围方面优于显微镜。我们发现肠道寄生虫，特别是蠕虫，是无处不在的Inhamudima，贝拉。然而，要实现对所有物种的高诊断灵敏度是一个挑战。经典的技术，如FEC是有用的一些肠道蠕虫物种的检测，但他们缺乏其他寄生虫物种的敏感性。PCR可以更准确地检测肠道寄生虫，但通常在资源匮乏的环境中不可行，至少在外围实验室中不可行。因此，需要一种更加现场友好、灵敏的方法来现场诊断寄生虫感染。在因贫困而生活条件恶劣的人群中，可以观察到各种各样的肠道寄生虫感染。这些感染通常通过粪便显微镜诊断，但如果使用的程序不准确或以次优的方式进行，则很容易错过。在本研究中，我们调查了肠道寄生虫感染的患病率在贝拉，莫桑比克的非正式解决。我们还比较了五种不同的显微镜技术和实时PCR检测五种蠕虫和五种原生动物的DNA的诊断性能。为此目的，从63户家庭的成员中收集了一份粪便样本，这些家庭均匀分布在定居点内。在303个检查样本中发现寄生虫感染非常丰富。几乎所有的个体都被发现感染了至少一种蠕虫，大多数粪便显示出多种寄生虫。没有一种经典的显微镜技术适合检测所有不同的病原物种。因此，必须将几种显微镜检查程序的结果结合起来才能得到完整的图像。我们发现PCR是最准确的诊断方法，即使在这种高度流行的设置。然而，DNA检测是一项高科技技术，一般不适用于资源匮乏的环境。
Many different intestinal parasite species can co-occur in the same population. However, classic diagnostic tools can only frame a particular group of intestinal parasite species. Hence, one or two tests do not suffice to provide a complete picture of infecting parasite species in a given population. The present study investigated intestinal parasitic infections in Beira, Mozambique, i.e. in the informal settlement of Inhamudima. Diagnostic accuracy of five classical microscopy techniques and real-time PCR for the detection of a broad spectrum of parasites was compared. A cross-sectional population-based survey was performed. One stool sample per participant (n = 303) was examined by direct smear, formal-ether concentration (FEC), Kato smear, Baermann method, coproculture and real-time PCR. We found that virtually all people (96%) harbored at least one helminth, and that almost half (49%) harbored three helminths or more. Remarkably, Strongyloides stercoralis infections were widespread with a prevalence of 48%, and Ancylostoma spp. prevalence was higher than that of Necator americanus (25% versus 15%), the hookworm species that is often assumed to prevail in East-Africa. Among the microscopic techniques, FEC was able to detect the broadest spectrum of parasite species. However, FEC also missed a considerable number of infections, notably S. stercoralis, Schistosoma mansoni and G. intestinalis. PCR outperformed microscopy in terms of sensitivity and range of parasite species detected. We showed intestinal parasites—especially helminths—to be omnipresent in Inhamudima, Beira. However, it is a challenge to achieve high diagnostic sensitivity for all species. Classical techniques such as FEC are useful for the detection of some intestinal helminth species, but they lack sensitivity for other parasite species. PCR can detect intestinal parasites more accurately but is generally not feasible in resource-poor settings, at least not in peripheral labs. Hence, there is a need for a more field-friendly, sensitive approach for on-the-spot diagnosis of parasitic infections. In populations living in adverse conditions due to poverty, a wide variety of intestinal parasite infections can be observed. These infections are usually diagnosed by stool microscopy, but can be easily missed if the procedures used are inaccurate or performed in a suboptimal way. In the present study, we investigated the prevalence of intestinal parasite infections in an informal settlement in Beira, Mozambique. We also compared the diagnostic performance of five different microscopic techniques and real-time PCR for the detection of DNA of five helminth and five protozoa species. For this purpose, a single stool sample was collected from members of 63 households, evenly distributed within the settlement. Parasitic infections were found to be highly abundant in the 303 examined samples. Virtually all individuals were found to be infected with at least one helminth species and a majority of the stools showed multiple parasites. None of the classical microscopic techniques was suitable to detect all different pathogenic species. Hence, the outcome of several microscopy procedures had to be combined to get a complete picture. We found PCR to be the most accurate diagnostic approach, even in this hyper-endemic setting. However, DNA detection is a high-tech technology, generally not applicable in resource-poor settings.