Development of molecular approaches for the identification of transmission sites of schistosomiasis

Melo, Fábio Lopes de; Gomes, Ana Lisa do Vale; Barbosa, Constança Simões; Werkhauser, Roberto P.; Abath, Frederico G. C.

doi:10.1016/j.trstmh.2005.12.008

Cited by 51 publications

(47 citation statements)

References 16 publications

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“…In season I (autumn), we found that examination of 200 snails revealed one snail was positive by shedding method (0.5 %), three positive snails by crushing (1.5 %) and seven positive snails by PCR (3.5 %) (4 were previously negative by both methods in addition the three positive snails from shedding and crushing) and in season II (spring) we found that examination of 200 snails revealed two shedding snails (1 %),while there were three positive In season I the Sensitivity = 42.9 % and Specificity = 100 %. While in season II the Sensitivity = 50 % and Specificity = 100 % Melo et al (2006) who found that PCR allowed for the identification of infection in pools that were negative by the conventional methods which was able to detect S. mansoni infection in 37.5 % of the snail pools. Hamburger et al (2004) used the same technique for monitoring infected S. haematobium snails in Kenya.…”

Section: Discussionmentioning

confidence: 99%

Molecular approach for detecting early prepatent Schistosoma mansoni infection in Biomphalaria alexandrina snail host

et al. 2014

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The present study aimed to evaluate a polymerase chain reaction (PCR) assay used for detection of Schistosoma mansoni infection in Biomphalaria alexandrina snails in early prepatent period and to compare between it and the ordinary detection methods (shedding and crushing). Biomphalaria alexandrina snails are best known for their role as intermediate hosts of S. mansoni. DNA was extracted from infected snails in addition to noninfected ''negative control'' (to optimized the efficiency of PCR reaction) and subjected to PCR using primers specific to a partial sequence of S. mansoni fructose-1,6-bus phosphate aldolase (SMALDO). SMALDO gene was detected in the infected laboratory snails with 70, 85, and 100 % positivity at the 1st, 3rd, and 7th day of infection, respectively. In contrast, the ordinary method was not sensitive enough in detection of early prepatent infection even after 7 days of infection which showed only 25 % positivity. By comparing the sensitivity of the three methods, it was found that the average sensitivity of shedding method compared to PCR was 23.8 % and the average sensitivity of crushing method compared to PCR was 46.4 % while the sensitivity of PCR was 100 %. We conclude that PCR is superior to the conventional methods and can detect positive cases that were negative when examined by shedding or crushing methods. This can help in detection of the areas and times of high transmission which in turn will be very beneficial in planning of the exact timing of the proper control strategy.

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Section: Discussionmentioning

confidence: 99%

Molecular approach for detecting early prepatent Schistosoma mansoni infection in Biomphalaria alexandrina snail host

et al. 2014

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“…DNA was amplified by PCR using the primers; forward: (5 0 -TTAC-GATCAGGACCAGTGT-3 0 ), and reverse: (5 0 -CCGGA-CATCTAAGGGCATCA-3 0 ). It was designed to flank the majority of the region coding for the small subunit (SSU) rRNA gene (Melo et al 2006). PCR was carried out in 50 ll reactions using 10 mM Tris-HCl, 50 mM KCl, 0.1 mg/ml gelatin, 1.5 mM MgCl 2 , 0.2 mM of each dNTP, 50 pmols of each primer and 2.5 U of Taq DNA polymerase (Amersham Biosciences, Uppsala, Sweden).…”

Section: Dna Extractionmentioning

confidence: 99%

“…The WHO recommends that the major of researches on schistosomiasis should focus on the development and evaluation of new strategies and tools for control of the disease (WHO 2004). PCR-based techniques have been reported for the diagnosis of a huge number of infectious pathogens; however its application for the S. mansoni detection isn't widespread (Melo et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Digenetic larvae in Schistosome snails from El Fayoum, Egypt with detection of Schistosoma mansoni in the snail by PCR

et al. 2014

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The present study aims to detect the digenetic larvae infections in Bulinus truncatus and Biomphalaria alexandrina snails and also PCR detection of Schistosoma mansoni infection. The snails were collected from different branches of Yousef canal and their derivatives in El Fayoum Governorate. The snails were investigated for infection through induction of cercarial shedding by exposure to light and crushing of the snails. The shed cercariae were S. mansoni, Pharyngeate longifurcate type I and Pharyngeate longifurcate type II from B. alexandrina, while that found in B. truncatus were Schitosoma haematobium and Xiphidiocercaria species cercariae. The seasonal prevalence of infection was discussed. Polymerase chain reaction was used for the detection of S. mansoni in the DNA from field collected infected and non infected snails. The results of PCR showed that the pool of B. alexandrina snails which shed S. mansoni cercariae in the laboratory, gave positive reaction in the samples. Pooled samples of field collected B. alexandrina that showed negative microscopic shedding of cercariae gave negative and positive PCR in a consecutive manner. Accordingly, a latent infection in the snail (negative microscopic) could be detected by using PCR.

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“…1992 by designing a test in a single-tube nested PCR format in which the internal primers are separated from the components of the first round of amplification by immobilization onto the inside of the microtube. This approach has previously been used for the detection of Schistosoma mansoni and Plasmodium DNA (Abath et al, 2002;Melo et al, 2006;Montenegro et al, 2004), indicating that the method is appropriate for nested PCR targeting other sequences.The test was initially carried out using one of the serotype standards in each reaction tube. The detection limit of the STNPCR was at least 10 copies for DENV-1 and 100 copies for DENV-2 and DENV-3 ( Figure 1A); the sensitivity reported previously by Lanciotti et al(1992) was 100 copies for each serotype.…”

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confidence: 99%

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confidence: 99%

Single-tube nested PCR using immobilized internal primers for the identification of dengue virus serotypes

Gomes

Silva

Cordeiro

et al. 2007

Journal of Virological Methods

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Molecular techniques based on the detection of genomic sequences by reverse transcription (RT)-PCR, nested PCR, or real-time PCR have made possible the rapid diagnosis of dengue virus (DENV) infections, and these approaches have been accepted by clinical laboratories as the new standard method for the detection of dengue virus in acute-phase serum samples. One of these PCR-based assays, the two-step RT nested PCR (RT-NPCR) technique is used routinely in laboratories worldwide. In the present study, the two-step RT-NPCR as described by Lanciotti and collaborators (1992) was adapted to a novel single-tube nested PCR (STNPCR) format, which is less prone to cross-contamination and reduces reaction cost and time. When standards for each dengue serotype were tested, the detection limit of the STNPCR was at least 10 copies for DENV-1 and 100 copies for DENV-2 and DENV-3, whereas the detection limit for the two-step RT-NPCR was 100 copies for each serotype. Sera from 22 patients with confirmed DENV-3 infections and from 14 healthy individuals were then tested in the STNPCR format using the system described by Lanciotti as the reference standard. The results indicated a sensitivity of 75.9% (CI 95%,) and a specificity of 100% for the RT-STNPCR. Athough RT-STNPCR was less sensitive than the conventional twostep RT-NPCR for the detection of virus in serum samples, it was still adequately sensitive, and the advantages associated with a single-tube format may outweigh the somewhat lower assay sensitivity, making it useful for diagnosis in the field. Keywords nested PCR; diagnosis; dengue; single-tube Dengue virus is a mosquito-borne flavivirus and the most prevalent arbovirus in tropical and subtropical regions of Asia, Africa and Central and South America (Harris et al., 2000). There are four distinct serotypes, DENV-1, DENV-2, DENV-3 and DENV-4, all of which may cause an asymptomatic infection or a spectrum of diseases ranging from dengue fever (DF) to more * Corresponding author. Tel.: +; fax: +449. E-mail address: emarques@cpqam.fiocruz.br (E. T. A Marques). This manuscript is dedicated to the family and former students of Dr. Abath.Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. severe clinical forms such as dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) (Guzman and Kouri, 2004). In recent years, dengue virus infection has emerged as a major public health problem, with expanding geographical distribution and increasing epidemic activity (Guha-Sapir and Schimmer, 2005). NIH Public AccessAlthough dengue virus infection confers protective immunity to the ho...

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Development of molecular approaches for the identification of transmission sites of schistosomiasis

Cited by 51 publications

References 16 publications

Molecular approach for detecting early prepatent Schistosoma mansoni infection in Biomphalaria alexandrina snail host

Molecular approach for detecting early prepatent Schistosoma mansoni infection in Biomphalaria alexandrina snail host

Digenetic larvae in Schistosome snails from El Fayoum, Egypt with detection of Schistosoma mansoni in the snail by PCR

Single-tube nested PCR using immobilized internal primers for the identification of dengue virus serotypes

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