Observations on the morphology of adults and larval stages of <i>Oesophagostomum</i> sp. isolated from man in northern Togo and Ghana

Blotkamp, J.; Krepel, HP; Kumar, V.; Baéta, S.; Noordende, JM Van 't; Polderman, A. M.

doi:10.1017/s0022149x00012840

Cited by 57 publications

(51 citation statements)

References 15 publications

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“…Another explanation for the non-detection of hookworm positives with PCR might be that the hookworm eggs detected with the Kato–Katz and FLOTAC methods were from A. duodenale , a hookworm species that would not have been identified with the N. americanus -specific primers that we used in our PCR. Only the third-stage larvae of these helminths but not the morphological identical eggs allow a microscopic differentiation between A. duodenale and N. americanus 54. Studies that have undertaken differential diagnosis using coproculture in East Africa have shown that both A. duodenale and N. americanus do occur in East Africa but that the latter is the predominant species in the region 55–57…”

Section: Discussionmentioning

confidence: 99%

Diagnostic Accuracy of Kato–Katz, FLOTAC, Baermann, and PCR Methods for the Detection of Light-Intensity Hookworm and Strongyloides stercoralis Infections in Tanzania

Knopp¹,

Salim²,

Schindler³

et al. 2014

The American Society of Tropical Medicine and Hygiene

127

136

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Sensitive diagnostic tools are crucial for an accurate assessment of helminth infections in low-endemicity areas. We examined stool samples from Tanzanian individuals and compared the diagnostic accuracy of a real-time polymerase chain reaction (PCR) with the FLOTAC technique and the Kato–Katz method for hookworm and the Baermann method for Strongyloides stercoralis detection. Only FLOTAC had a higher sensitivity than the Kato–Katz method for hookworm diagnosis; the sensitivities of PCR and the Kato–Katz method were equal. PCR had a very low sensitivity for S. stercoralis detection. The cycle threshold values of the PCR were negatively correlated with the logarithm of hookworm egg and S. stercoralis larvae counts. The median larvae count was significantly lower in PCR false negatives than true positives. All methods failed to detect very low-intensity infections. New diagnostic approaches are needed for monitoring of progressing helminth control programs, confirmation of elimination, or surveillance of disease recrudescence.

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Section: Discussionmentioning

confidence: 99%

Diagnostic Accuracy of Kato–Katz, FLOTAC, Baermann, and PCR Methods for the Detection of Light-Intensity Hookworm and Strongyloides stercoralis Infections in Tanzania

Knopp¹,

Salim²,

Schindler³

et al. 2014

The American Society of Tropical Medicine and Hygiene

127

136

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“…recorded to date from non-human primates, O. bifurcum, O. stephanostomum, and O. aculeatum have also been reported in humans (Chabaud & Lariviere, 1958;Polderman & Blotkamp, 1995). Zoonosis caused by O. bifurcum is endemic in the northernmost part of Ghana and Togo situated in western Africa, and high prevalences of the disease in human residents have been recorded (Blotkamp et al, 1993;Polderman & Blotkamp, 1995;Pit et al, 1999;Yelifari et al, 2005;Gasser et al, 2006). Recently, however, multifaceted genetic analyses have demonstrated that different genotypes of O. bifurcum are prevalent in human patients and local non-human primates (Mona monkeys, Patas monkeys, Green monkeys, and Olive baboons) in Ghana and Togo (de Gruijter et al, 2004(de Gruijter et al, , 2005; reviewed by Gasser et al, 2006Gasser et al, , 2009, supporting parallel assump-HELMINTHOLOGIA, 51, 2: 83 -93, 2014 Prevalence and genetic diversity of Oesophagostomum stephanostomum in wild lowland gorillas at Moukalaba-Doudou National Park, Gabon tions based on epidemiological and morphological analyses de Gruijter et al, 2006).…”

Section: Introductionmentioning

confidence: 97%

Prevalence and genetic diversity of Oesophagostomum stephanostomum in wild lowland gorillas at Moukalaba-Doudou National Park, Gabon

et al. 2014

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Using a sedimentation method, the prevalence of the nodular worm Oesophagostomum stephanostomum (Nematoda: Strongylida) in western lowland gorillas at Moukalaba-Doudou National Park (MDNP), Gabon, was determined in fecal samples collected between January 2007 and October 2011, along with their coprocultures. Concurrently, possible zoonotic Oesophagostomum infections in villagers living near MDNP were assessed from their fecal samples collected during October and November of 2011. In the gorillas, strongylid (Oesophagostomum and/or hookworm) eggs were found in 47 of 235 fecal samples (20.0 %) and Oesophagostomum larvae were detected in 101 of 229 coprocultures (44.1 %). In the villagers, strongylid eggs were found in 9 of 71 fecal samples (12.7 %), but no Oesophagostomum larvae were detected in coprocultures. The internal transcribed spacer (ITS) region of ribosomal RNA gene (rDNA) and cytochrome c oxidase subunit-1 (cox-1) region of mitochondrial DNA (mtDNA) of coprocultured Oesophagostomum larvae were amplified using parasite DNA extracted from 7–25 larvae/sample, cloned into Escherichia coli, and sequenced. Sequenced rDNA contained 353/354-bp long ITS1, 151-bp long 5.8S rDNA, and 227-bp long ITS2. Parts of clones showed variations at 1–3 bases in the ITS1 region at a frequency of 24/68 (35.3 %) and at 1–2 bases in the ITS2 region at a frequency of 7/68 (10.3 %), whereas the 5.8S rDNA was essentially identical. Sequenced cox-1 gene of the parasites, 849 bp in length, showed a higher number of nucleotide variations, mainly at the third nucleotide position of the codon. The majority of clones (27/41 (65.9 %)) had an identical amino acid sequence. These results suggest that at MDNP, Gabon, only a single population of O. stephanostomum with a degree of genetic diversity is prevalent in western lowland gorillas, without zoonotic complication in local inhabitants. The possible genetic variations in the ITS region of rDNA and cox-1gene of mtDNA presented here may be valuable when only a limited amount of material is available for the molecular species diagnosis of O. stephanostomum.

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“…The taxonomy of the species important for human disease was studied by Chabaud and Lariviere and by Blotkamp, who recognized Oesophagostomum bifurcum as the most prevalent parasite in humans [4,5]. Although the disease is most often found in West Africa, sporadic cases have been described in other parts of Africa, Asia and South America [1,6,11,13,15].…”

Section: Introductionmentioning

confidence: 99%

Human oesophagostomiasis: a histomorphometric study of 13 new cases in northern Ghana

Bogers

Storey

Faile³

et al. 2001

Virchows Arch

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Oesophagostomiasis is an infrequently described and recognised parasitic infection in humans, caused by Oesophagostomum bifurcum. Although the disease is most often found in the northern part of Togo and the neighbouring part of Ghana, sporadic cases have been described in other parts of Africa and in Asia and South America: Uganda, Ivory Coast, Sudan, Kenya, Ethiopia, Indonesia, Malaysia and Brazil. Infection probably occurs by way of the ingestion of L3 larvae. These larvae penetrate the intestinal wall, especially that of the colon. Some of these larvae develop into young adult worms and return to the bowel lumen. Other larvae, however, develop into immature worms, which fail to settle in the lumen, forming abscesses in the bowel wall and causing pathology. In the literature 105 human cases have been described, many originating in the northern regions of Ghana and Togo. The present study was performed to evaluate 13 new cases originating in the northern part of Ghana (7 female and 6 male patients, aged between 2 and 60 years). Histopathologically, the patients could be divided into two groups: the first group showed multinodular disease, while patients in the second group presented with a single, nodular mass. In the first group, abscesses were seen throughout the colonic wall. The mean size of the cavities was 4.3+/-0.7 mm. There was no relation between the size and the localisation in the colonic wall. Abscesses were significantly larger in male patients than in female patients. There was no correlation with age. In the second group, histopathological examination showed a cyst of variable wall thickness with very limited inflammation. These cysts represented older lesions, often encapsulated in the mesentery. In conclusion, in this study we present 13 new cases of human oesophagostomiasis. The abscess formation was found to be organ specific, independent of age, and gender-related, producing a more intense tissue reaction in male patients.

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Observations on the morphology of adults and larval stages of Oesophagostomum sp. isolated from man in northern Togo and Ghana

Cited by 57 publications

References 15 publications

Diagnostic Accuracy of Kato–Katz, FLOTAC, Baermann, and PCR Methods for the Detection of Light-Intensity Hookworm and Strongyloides stercoralis Infections in Tanzania

Diagnostic Accuracy of Kato–Katz, FLOTAC, Baermann, and PCR Methods for the Detection of Light-Intensity Hookworm and Strongyloides stercoralis Infections in Tanzania

Prevalence and genetic diversity of Oesophagostomum stephanostomum in wild lowland gorillas at Moukalaba-Doudou National Park, Gabon

Human oesophagostomiasis: a histomorphometric study of 13 new cases in northern Ghana

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