Low transmission areas of schistosomiasis in Venezuela: consequences on the diagnosis, treatment, and control

Noya, Belkisyolé Alarcón de; Guevara, Raiza Ruiz; Colmenares, Cecilia; Losada, Sandra; Noya, Óscar

doi:10.1590/s0074-02762006000900006

Cited by 20 publications

(9 citation statements)

References 23 publications

(19 reference statements)

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“…The detection of schistosome eggs in feces or in urine is particularly insensitive for detection of low-level or light infections, 7 and in primate models, egg counts and circulating antigen tests regularly miss detection of infection intensities of up to 10-20 worm pairs per person. 8 Infection surrogates, such as microhaematuria in S. haematobium infection, also lose their diagnostic reliability in low-level infections, 9 and positive antibody test results (indicative of Schistosoma exposure) may take an indefinite period of time to convert to negativity after elimination of infection.…”

Section: Introductionmentioning

confidence: 99%

Detection of Schistosoma mansoni and Schistosoma haematobium DNA by Loop-Mediated Isothermal Amplification: Identification of Infected Snails from Early Prepatency

Abbasi¹,

King²,

Muchiri³

et al. 2010

The American Journal of Tropical Medicine and Hygiene

104

125

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Section: Introductionmentioning

confidence: 99%

Detection of Schistosoma mansoni and Schistosoma haematobium DNA by Loop-Mediated Isothermal Amplification: Identification of Infected Snails from Early Prepatency

Abbasi¹,

King²,

Muchiri³

et al. 2010

The American Journal of Tropical Medicine and Hygiene

104

125

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“…Somewhat similarly, the saline gradient method is a simple procedure that uses a salt gradient to purify eggs to allow for easier detection with microscopic examination. Serological antibody detection assays, including ELISAs with a variety of antigen preparations ( de Noya et al 2007 ), have also been used as tools to diagnose schistosomiasis. Although these methods are low-cost, reproducible, objective, rapid and potentially automatable ( de Noya et al 2006 ), they are poor at distinguishing between past and present infections.…”

mentioning

confidence: 99%

A conventional polymerase chain reaction-based method for the diagnosis of human schistosomiasis in stool samples from individuals in a low-endemicity area

Carneiro

Peralta

Pinheiro

et al. 2013

Mem. Inst. Oswaldo Cruz

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The aim of this study was to evaluate the efficacy of a polymerase chain reaction (PCR)-based method to detect Schistosoma mansoni DNA in stool samples from individuals living in a low-endemicity area in Brazil. Of the 125 initial stool samples, 80 were ELISA reactive and eggs were identified in 19 of the samples by parasitological examination. For the PCR evaluations, 56 stool samples were selected and divided into five groups. Groups I-IV were scored negative for S. mansoni eggs by parasitological examination. Groups I and II were ELISA reactive, whereas Groups III and IV were ELISA nonreactive. Groups II and III were positive for other intestinal parasites. PCR testing scored eight samples as positive from these four groups. Group V represented the S. mansoni -positive group and it included ELISA-reactive samples that were scored positive for S. mansoni by one or more parasitological examinations (6/19 were positive by Kato-Katz method, 9/17 by saline gradient and 10/13 by Helmintex®). PCR scored 13 of these 19 samples as positive for S. mansoni . We conclude that while none of these methods yielded 100% sensitivity, a combination of techniques should be effective for improving the detection of S. mansoni infection in low-endemicity areas.

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“…In the 250 individuals evaluated, 118 (47.2%) were seropositive, whereas only 40 (16%) were parasitologically positive. In this seropositivity there is certainly a portion of individuals who have been cured with treatment, since the technique does not distinguish between active and past infections 10 , and another portion that represents the non-specificity of test, which can occur due to frequent similarity between the constituent antigens of the parasite 19 .…”

Section: Discussionmentioning

confidence: 99%

“…With the transition to lower morbidity, more sensitive diagnostic methods are needed 9 . In this context, the enzyme-linked immunosorbent assay (ELISA) immunological technique has been proposed for use in the PCE 10 . It is important to conduct studies about…”

Section: Palavrasmentioning

confidence: 99%

Increased detection of schistosomiasis with Kato-Katz and SWAP-IgG-ELISA in a Northeastern Brazil low-intensity transmission area

Carneiro

Pinheiro

Oliveira

et al. 2012

Rev. Soc. Bras. Med. Trop.

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Introduction:The laboratory diagnosis of schistosomiasis is based mainly on the detection of parasite eggs in stool samples through the Kato-Katz (KK) technique, reading one slide by test. However, a widely known limitation of parasitological methods is reduced sensitivity, particularly in low endemic areas. Methods: To increase sensitivity, we conducted further slide readings from the same stool sample using the parasitological method associated with a serological test. We used the KK method (three slides) and the IgG anti-Schistosoma mansonienzyme-linked immunosorbent assay (ELISA) technique to diagnose schistosomiasis in low endemic areas in the Brazilian State of Ceará. Fecal samples and sera from 250 individuals were analyzed. Results: Sixteen percent and 47.2% of samples were positive in parasitological tests and serological tests, respectively. Parasitological methods showed that 32 (80%) individuals tested positive on the first slide, 6 (15%) on the second slide, and 2 (5%) on the third. The performance of the ELISA test in the diagnosis, using the KK method as diagnostic reference, showed a negative predictive value of 100%, with specificity and positive predictive values of 62.8% and 33.9%, respectively. Conclusions: In this study, the increase from one to three slides analyzed per sample using the KK technique was shown to be a useful procedure for increasing the diagnostic sensitivity of this technique.

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Low transmission areas of schistosomiasis in Venezuela: consequences on the diagnosis, treatment, and control

Abstract: Schistosomiasis low transmission areas as

Cited by 20 publications

References 23 publications

Detection of Schistosoma mansoni and Schistosoma haematobium DNA by Loop-Mediated Isothermal Amplification: Identification of Infected Snails from Early Prepatency

Detection of Schistosoma mansoni and Schistosoma haematobium DNA by Loop-Mediated Isothermal Amplification: Identification of Infected Snails from Early Prepatency

A conventional polymerase chain reaction-based method for the diagnosis of human schistosomiasis in stool samples from individuals in a low-endemicity area

Increased detection of schistosomiasis with Kato-Katz and SWAP-IgG-ELISA in a Northeastern Brazil low-intensity transmission area

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