Meurs Lynn, Polderman Anton M, Vinkeles Melchers Natalie V S, Brienen Eric A T, Verweij Jaco J, Groosjohan Bernhard, Mendes Felisberto, Mechendura Manito, Hepp Dagmar H, Langenberg Marijke C C, Edelenbosch Rosanne, Polman Katja, van Lieshout Lisette
Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands.
Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.
PLoS Negl Trop Dis. 2017 Jan 23;11(1):e0005310. doi: 10.1371/journal.pntd.0005310. eCollection 2017 Jan.
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.
METHODOLOGY/PRINCIPAL FINDINGS: 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.
CONCLUSIONS/SIGNIFICANCE: 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.
许多不同种类的肠道寄生虫可在同一人群中共存。然而，传统的诊断工具只能针对特定的一组肠道寄生虫种类。因此，一两项检测不足以全面了解特定人群中感染的寄生虫种类。本研究调查了莫桑比克贝拉市因哈穆迪马非正式定居点的肠道寄生虫感染情况。比较了五种传统显微镜技术和实时荧光定量PCR检测多种寄生虫的诊断准确性。
方法/主要发现：开展了一项基于人群的横断面调查。对每位参与者（n = 303）的一份粪便样本进行直接涂片、甲醛-乙醚浓缩法（FEC）、加藤涂片法、贝尔曼法、粪便培养和实时荧光定量PCR检测。我们发现几乎所有人（96%）都感染了至少一种蠕虫，近一半（49%）的人感染了三种或更多种蠕虫。值得注意的是，粪类圆线虫感染很普遍，患病率为48%，钩虫属的患病率高于美洲板口线虫（25%对15%），而美洲板口线虫通常被认为是东非流行的钩虫种类。在显微镜技术中，FEC能够检测到最广泛的寄生虫种类。然而，FEC也遗漏了相当数量的感染病例，尤其是粪类圆线虫、曼氏血吸虫和肠贾第虫。在检测寄生虫种类的敏感性和范围方面，PCR优于显微镜检查。
结论/意义：我们发现贝拉市因哈穆迪马的肠道寄生虫，尤其是蠕虫，无处不在。然而，对所有种类实现高诊断敏感性是一项挑战。FEC等传统技术对检测某些肠道蠕虫种类有用，但对其他寄生虫种类缺乏敏感性。PCR能够更准确地检测肠道寄生虫，但在资源匮乏地区通常不可行，至少在外围实验室不行。因此，需要一种更便于现场操作、敏感的方法来进行寄生虫感染的现场诊断。
