A technique for identification of cercariae of<i>Schistosoma haematobium, S. curassoni, S. bovis</i>and<i>S. intercalatum</i>

Cabaret, Jacques; Bayssade-Dufour, Ch.; Albaret, J.-L.; Ngendahayo, L. D.; Chabaud, A. G.

doi:10.1051/parasite/1990652061

Cited by 8 publications

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“…Developmental instability may be associated with 'small and localized external environmental effects, or with significant perturbations of the internal epigenetic system' (Schlichting and Pigliucci, 1998). Cabaret et al (1990), after investigating 84 samples or isolates of Schistosoma spp., observed that mis-classification was much more likely when the samples came from experimental infections than when they were wild-collected. The effects of S. mansoni switching the species it uses as a vertebrate host, from rodent to human or vice versa, could mimic those of the environmental changes that are usually responsible for altering the expression of reaction norms in other organisms.…”

Section: Discussionmentioning

confidence: 99%

“…Attempts were made to estimate three CI, named AD, AL and U after the sensory receptors, for each cercaria (Bayssade-Dufour et al, 1989;Cabaret et al, 1990). Only cercariae for which full or almost full data were available were included in the final analysis.…”

Section: Methodsmentioning

confidence: 99%

“…Bayssade-Dufour et al (1989) described a multivariate statistical procedure, based on the estimation of various cercarial indices (CI), including measurements of the position of antero-dorsal (AD), antero-lateral (AL) and tail-stem (U) sensory receptors, that could be used to distinguish three species of Schistosoma. Subsequently, Cabaret et al (1990) used a modification of the same procedure to distinguish four African species of schistosomes. CI may be particularly relevant in the epidemiology of schistosomiasis.…”

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confidence: 99%

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Phenotypic plasticity in the cercarial indices of human and rodent samples ofSchistosoma mansoni(Digenea: Schistosomatidae)

Bogéa¹

2005

Annals of Tropical Medicine & Parasitology

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In the epidemiology of schistosomiasis, the cercarial index (CI) has been used for several purposes, including the identification of the species of vertebrate host involved in transmission in a particular setting. The CI of samples of Schistosoma mansoni of human (BH) and rodent (CMO) origin have now been compared, in an attempt to identify morphological markers on cercariae that would indicate whether the eggs from which the cercariae have developed were produced in humans or in rodents. After silver-nitrate impregnation of the cercariae, the CI (and their reaction norms) for the antero-dorsal (AD), antero-lateral (AL) and tail-stem (U) sensory receptors were investigated. The data analysis was based on linear-regression methods, Levene's test for the equality of variances, pooled-variance independent t-tests, and discriminant analysis. The results indicated that CI varied with vertebrate-host origin, that the AD reaction norms were more consistent and plastic than the other reaction norms investigated, that there appeared to be no simple allometric relationship between any of the CI investigated and cercarial body length, and that the BH sample gave larger standard deviations and a higher incidence of mis-classification than the CMO, indicating some developmental instability in the sample of human origin. The relative instability of the BH sample was, however, possibly the result of the experimental procedures. As the parasites used to produce the BH sample had been isolated from humans fairly recently and then routinely maintained in mice, host-induced selection could have affected the sample, altering its CI and their reaction norms. The results of the discriminant analysis indicated that, of the indices investigated, AD was the best morphological marker for distinguishing human and rodent samples of S. mansoni.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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confidence: 99%

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Phenotypic plasticity in the cercarial indices of human and rodent samples ofSchistosoma mansoni(Digenea: Schistosomatidae)

Bogéa¹

2005

Annals of Tropical Medicine & Parasitology

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“…Des travaux rrcents (Bayssade-Dufour et al, 1989;Ngendahayo, 1989;Cabaret et al, 1990) (Ross et al, 1987), sur la forme et la localisation des oeufs chez l'h6te vert6br6 ou sur plusieurs de ces carac-t~res.…”

Section: Inwoducfionunclassified

Identification des cercaires de Schistosoma africains émises par Bulinus umbilicatus, B. truncatus et B. forskalii

Albaret¹,

Bayssade-Dufour²,

Ngendahayo³

1993

Syst Parasitol

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Three chaetotaxic indices, AD, AL and U, of cercariae of four pre-identified African Schistosoma species, obtained from natural or experimental infections, were established. AD and AL correspond respectively to the relative distance between the dorsal and lateral papillae. U corresponds to the total number of tail stem papillae. The simple comparison of average values of one or two of these three indices facilitated identification of the cercariae of Schistosoma haematobium and S. curassoni emitted by Bulinus umbilicatus, cercariae of S. haematobium and S. bovis shed by B. truncatus, and cercariae of S. boris and S. intercalatum emitted by B. forskalii.

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“…Only a precise analyse of papillae distribution on cercariae surface (i.e. Chaetotaxy) allows to distinguish these larvae at a species level [12]. Various molecular technics have been developed to achieve this task [13–16] but they remain expensive and time-consuming.…”

Section: Introductionmentioning

confidence: 99%

MALDI-TOF : A new tool for the identification of Schistosoma cercariae and detection of hybrids

Huguenin

Kincaid-Smith

Depaquit

et al. 2022

Preprint

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Schistosomiasis is a neglected water-born parasitic disease caused by Schistosoma affecting more than 200 million people. Introgressive hybridization is common among these parasites and raises issues concerning their zoonotic transmission. Morphological identification of Schistosoma cercariae is difficult and does not permit hybrids detection. Our objective was to assess the performance of MALDI-TOF for the specific identification of cercariae in human and non-human Schistosoma and for the detection of hybridization between S. bovis and S. haematobium Spectra were collected from laboratory reared molluscs infested with strains of S. haematobium , S. mansoni , S . bovis , S. rodhaini and S. bovis x S. haematobium natural (Corsican hybrid) and artificial hybrids. Cluster analysis showed a clear separation between S. haematobium , S. bovis , S. mansoni and S. rodhaini. Corsican hybrids are classified with those of the parental strain of S. haematobium whereas other hybrids formed a distinct cluster. In blind test analysis the developed MALDI-TOF spectral database permits identification of Schistosoma cercariae with high accuracy (94%) and good specificity ( S. bovis : 99.59%, S. haematobium 99.56%, S. mansoni and S. rodhaini : 100%). Most misidentifications were between S. haematobium and the Corsican hybrids. The use of machine learning permits to improve the discrimination between these last two taxa, with accuracy, F1 score and Sensitivity/Specificity > 97%. In multivariate analysis the factors associated with obtaining a valid identification score (> 1.7) were absence of ethanol preservation (p < 0.001) and a number of 2-3 cercariae deposited per well (p < 0.001). Also spectra acquired from S. mansoni cercariae are more likely to obtain a valid identification score than those acquired from S. haematobium (p<0.001). MALDI-TOF is a reliable technique for high-throughput identification of Schistosoma cercariae of medical and veterinary importance and could be useful for field survey in endemic areas.

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A technique for identification of cercariae ofSchistosoma haematobium, S. curassoni, S. bovisandS. intercalatum

Cited by 8 publications

References 0 publications

Phenotypic plasticity in the cercarial indices of human and rodent samples ofSchistosoma mansoni(Digenea: Schistosomatidae)

Phenotypic plasticity in the cercarial indices of human and rodent samples ofSchistosoma mansoni(Digenea: Schistosomatidae)

Identification des cercaires de Schistosoma africains émises par Bulinus umbilicatus, B. truncatus et B. forskalii

MALDI-TOF : A new tool for the identification of Schistosoma cercariae and detection of hybrids

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