Diagnosis of Human Trematode Infections

Esteban, J. Guillermo; Muñoz-Antolí, Carla; Toledo, Rafael; Ash, Lawrence R.

doi:10.1007/978-1-4939-0915-5_9

Cited by 15 publications

(8 citation statements)

References 181 publications

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“…Additionally, stool examination lacks analytical sensitivity, particularly for light infections, requiring serial fecal sampling and an intensive effort in resource-poor settings [35]. To solve these limitations, many immunological and molecular diagnostic approaches have already been developed and applied to detect the presence of several human zoonotic trematode infections with varying accuracy [36, 37]. …”

Section: Discussionmentioning

confidence: 99%

LAMPhimerus: A novel LAMP assay for detecting Amphimerus sp. DNA in human stool samples

et al. 2017

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BackgroundAmphimeriasis is a fish-borne disease caused by the liver fluke Amphimerus spp. that has recently been reported as endemic in the tropical Pacific side of Ecuador with a high prevalence in humans and domestic animals. The diagnosis is based on the stool examination to identify parasite eggs, but it lacks sensitivity. Additionally, the morphology of the eggs may be confounded with other liver and intestinal flukes. No immunological or molecular methods have been developed to date. New diagnostic techniques for specific and sensitive detection of Amphimerus spp. DNA in clinical samples are needed.Methodology/Principal findingsA LAMP targeting a sequence of the Amphimerus sp. internal transcribed spacer 2 region was designed. Amphimerus sp. DNA was obtained from adult worms recovered from animals and used to optimize the molecular assays. Conventional PCR was performed using outer primers F3-B3 to verify the proper amplification of the Amphimerus sp. DNA target sequence. LAMP was optimized using different reaction mixtures and temperatures, and it was finally set up as LAMPhimerus. The specificity and sensitivity of both PCR and LAMP were evaluated. The detection limit was 1 pg of genomic DNA. Field testing was done using 44 human stool samples collected from localities where fluke is endemic. Twenty-five samples were microscopy positive for Amphimerus sp. eggs detection. In molecular testing, PCR F3-B3 was ineffective when DNA from fecal samples was used. When testing all human stool samples included in our study, the diagnostic parameters for the sensitivity and specificity were calculated for our LAMPhimerus assay, which were 76.67% and 80.77%, respectively.Conclusions/SignificanceWe have developed and evaluated, for the first time, a specific and sensitive LAMP assay for detecting Amphimerus sp. in human stool samples. The procedure has been named LAMPhimerus method and has the potential to be adapted for field diagnosis and disease surveillance in amphimeriasis-endemic areas. Future large-scale studies will assess the applicability of this novel LAMP assay.

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Section: Discussionmentioning

confidence: 99%

LAMPhimerus: A novel LAMP assay for detecting Amphimerus sp. DNA in human stool samples

et al. 2017

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“…Concentration techniques using formalin-ether or centrifugation are therefore used in hospital laboratories to detect light infections (81) . However, difficulty in using egg morphology to differentiate species of liver fluke, and even confusion with intestinal flukes or non-pathogenic trematodes, reduces the specificity and sensitivity of this method (81,82) .…”

Section: Parasitological Diagnosismentioning

confidence: 99%

“…However, difficulty in using egg morphology to differentiate species of liver fluke, and even confusion with intestinal flukes or non-pathogenic trematodes, reduces the specificity and sensitivity of this method (81,82) . Therefore eggs of light, or early infections may not be detected (24,83) .…”

Section: Parasitological Diagnosismentioning

confidence: 99%

Human liver flukes

Harrington

Lamberton

McGregor

2017

The Lancet Gastroenterology & Hepatology

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“…Despite numerous technological advances in the diagnosis of soil-transmitted helminth (STH) infections, such as the development of multiplex and multi-parallel fecal DNA assays [ 1 , 2 ], coprological microscopy techniques remain the standard for diagnosing these infections in humans [ 3 ], including the McMaster (MM) counting method [ 4 ] and the Kato-Katz (KK) fecal thick smear [ 5 ]. This is due to their simplicity, ease-of-use in the field, and low cost.…”

Section: Introductionmentioning

confidence: 99%

The Right Tool for the Job: Detection of Soil-Transmitted Helminths in Areas Co-endemic for Other Helminths

et al. 2015

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BackgroundDue to the recent increased use of the McMaster (MM) fecal egg counting method for assessing benzimidazole drug efficacy for treating soil-transmitted helminth (STH) infections, the aim of the current study was to determine the operational value of including the MM method alongside the Kato-Katz (KK) fecal thick smear to increase the diagnostic sensitivity when STHs are co-endemic with trematode helminths (e.g., Schistosoma mansoni).MethodsA cross-sectional study was conducted in school-aged children aged 4-18 years in the northeastern region of the State of Minas Gerais (Brazil), where Necator americanus, Ascaris lumbricoides, Trichuris trichiura, and S. mansoni are co-endemic. One fecal sample from each participant was collected and transported to the field laboratory for analysis. Coprological diagnosis was performed on each fecal sample by three different methods: Formalin-Ether Sedimentation (FES), KK and the MM technique. The diagnostic sensitivity and negative predictive value (NPV) of each technique was calculated using the combination of all three techniques as the composite standard. In order to determine the agreement between the three techniques Fleiss´ kappa was used. Both the Cure Rate (CR) and the Fecal Egg Count Reduction (FECR) were calculated using the two quantification techniques (i.e., the MM and KK).ResultsFecal samples from 1260 children were analyzed. The KK had higher diagnostic sensitivity than the MM for the detection of both A. lumbricoides (KK 97.3%, MM 69.5%) and hookworm (KK 95.1%, MM 80.8%). The CR of a single dose of mebendazole varied significantly between the KK and MM for both A. lumbricoides (p = 0.016) and hookworm (p = 0.000), with lower rates obtained with the KK. On the other hand, the FECR was very similar between both techniques for both A. lumbricoides and hookworm.ConclusionThe MM did not add any diagnostic value over the KK in areas where both STHs and trematodes were co-endemic. The lower sensitivity of the MM would have an important impact on the administration of selective school-based treatment in this area since if only the MM were used, 36 (13.9%) children diagnosed with A. lumbricoides would have gone untreated.

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Diagnosis of Human Trematode Infections

Cited by 15 publications

References 181 publications

LAMPhimerus: A novel LAMP assay for detecting Amphimerus sp. DNA in human stool samples

LAMPhimerus: A novel LAMP assay for detecting Amphimerus sp. DNA in human stool samples

Human liver flukes

The Right Tool for the Job: Detection of Soil-Transmitted Helminths in Areas Co-endemic for Other Helminths

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