Evaluation of techniques for the diagnosis of Strongyloides stercoralis in human immunodeficiency virus (HIV) positive and HIV negative individuals in the city of Itajaí, Brazil

Blatt, Jucelene Marchi; Cantos, Geny Aparecida

doi:10.1590/s1413-86702003000600008

Cited by 50 publications

(41 citation statements)

References 18 publications

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“…The study population in Argentina had not been treated with anthelmintics for a period of at least 6 months prior to the survey. Our data are in agreement with those from a survey in Peru in which an ELISA was more sensitive than a comprehensive single stool evaluation and in which sedimentation concentration is more sensitive than Baermann and agar plate tests (29), which have been reported as the most sensitive in several reports (7,17,24,26).…”

Section: Discussionsupporting

confidence: 91%

Improved Diagnosis of Strongyloides stercoralis Using Recombinant Antigen-Based Serologies in a Community-Wide Study in Northern Argentina

Krolewiecki

Ramanathan

Fink

et al. 2010

Clin Vaccine Immunol

126

127

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The serodiagnosis of Strongyloides stercoralis infection by enzyme-linked immunosorbent assays based on crude antigen (CrAg-ELISA), while useful, has been limited by the reliance on crude parasite extracts. Newer techniques such as the luciferase immunoprecipitation system assay (LIPS), based on a 31-kDa recombinant antigen (termed NIE) from S. stercoralis and/or the recombinant antigen S. stercoralis immunoreactive antigen (SsIR), or the NIE-ELISA have shown promise in controlled settings. We compared each of these serologic assays in individuals from both regions of the world in which S. stercoralis is endemic and those in which it is not. A comprehensive stool evaluation (sedimentation concentration, Baermann concentration with charcoal cultures, agar plate, and Harada-Mori) and four different serologic techniques using CrAg-ELISA or recombinant NIE-ELISA as well as LIPS using NIE alone or in combination with a second recombinant antigen (NIE/SsIR-LIPS) were compared among individuals with parasitologically proven infection (n ‫؍‬ 251) and healthy controls from regions of the world in which the infection is nonendemic (n ‫؍‬ 11). Accuracy was calculated for each assay. The prevalence of S. stercoralis infection was 29.4% among Argentinean stool samples (n ‫؍‬ 228). Sedimentation concentration and Baermann were the most sensitive stool-based methods. NIE-LIPS showed the highest sensitivity (97.8%) and specificity (100%) of the serologic assays. The calculated negative predictive value was highest for both the NIE-LIPS and CrAg-ELISA (>97%) irrespective of disease prevalence. No cross-reactivity with soil-transmitted helminths was noted. NIE-LIPS compares favorably against the current CrAg-ELISA and stool evaluation, providing additional accuracy and ease of performance in the serodiagnosis of S. stercoralis infections irrespective of disease prevalence.

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Section: Discussionsupporting

confidence: 91%

Improved Diagnosis of Strongyloides stercoralis Using Recombinant Antigen-Based Serologies in a Community-Wide Study in Northern Argentina

Krolewiecki

Ramanathan

Fink

et al. 2010

Clin Vaccine Immunol

126

127

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“…However, controversial results achieved for Baermann concentration in comparison to other methods ranged from 48.5 to 100 % (Blatt and Cantos 2003;Steinmann et al 2007) (Table 2). …”

Section: Discussionmentioning

confidence: 98%

Geohelminths distribution as affected by soil properties, physicochemical factors and climate in Sharkyia governorate Egypt

et al. 2014

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Soil-transmitted helminths are mainly a group of parasitic nematodes causing human infection through contact with parasite eggs or larvae; they survive in the warm and moist soil of the tropical and subtropical countries. This study was carried out in Sharkyia governorate from October, 2011 to October, 2013, to correlate between the prevalence and distribution of these parasites in the soil and the physicochemical factors affecting the examined samples of the soil. One hundred and twenty samples of different types of soil (clay, silt, sand) from different localities were collected and examined. Diagnosis of geohelminths was confirmed by the recovery of their eggs and larvae with other protozoa by different parasitological methods. The modified baermann method was found to be more efficient in detection of geohelminths larvae than charcoal culture method. Among the examined sites geohelminths were much more numerous in the soil of rural areas especially in the spring and summer seasons, while the contamination of canal banks by geohelminths was the worst (80 %). An insignificant correlation was reported between the soil texture and the number of positive samples in the examined areas while the relationship was directly proportional among (moisture, PH, organic). It appeared that the most common geohelminthic stage was Toxocara spp. eggs besides other types of protozoa especially Balantidium coli cysts. This suggests that factors other than soil texture are important in the prevalence of geohelminths in the soil e.g. temperature, moisture, PH and organic matter. So, to change some of these factors in a trial to control geoparasites transmission but with keeping the environment should be tried. These results also open the way to further studies to highlight the mutual affection between inhabitants of these sites and the prevalence of these geoparasites.

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“…QFEC could substitute for APC only when the parasite load was higher than 50 larvae per g of stool. This study serves as a good reminder to those conducting stool exams about the sensitivity and specificity limitations of both techniques.Agar plate culture (APC) is a highly effective technique for the coprological diagnosis of human strongyloidiasis (1,(5)(6)(7)(8)10). But despite its high sensitivity, there are several disadvantages to APC.…”

mentioning

confidence: 99%

Comparison of the Quantitative Formalin Ethyl Acetate Concentration Technique and Agar Plate Culture for Diagnosis of Human Strongyloidiasis

Intapan

Maleewong

Wongsaroj³

et al. 2005

J Clin Microbiol

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The quantitative formalin ethyl acetate concentration technique (QFEC) was compared to agar plate culture (APC) for the detection of Strongyloides stercoralis larvae. QFEC could substitute for APC only when the parasite load was higher than 50 larvae per g of stool. This study serves as a good reminder to those conducting stool exams about the sensitivity and specificity limitations of both techniques.Agar plate culture (APC) is a highly effective technique for the coprological diagnosis of human strongyloidiasis (1,(5)(6)(7)(8)10). But despite its high sensitivity, there are several disadvantages to APC. It is expensive, it takes a long time before results can be provided, and there is also a risk of infection for the technicians. The quantitative formalin ethyl acetate concentration technique (QFEC) is another effective and more rapid method to detect and quantify intestinal helminths, e.g., Ascaris lumbricoides (3) and Opisthorchis viverrini (4). In the present study, we compared APC results to the different intensities of Strongyloides stercoralis larvae determined by QFEC.Stool samples (n ϭ 1,233) were collected from populations in northeast Thailand and examined by APC (6) and QFEC (3). For APC, 3-g portions of individual fecal samples were placed in the centers of nutrient agar plates during the field survey. The plates were kept in a box and transported at room temperature (30 to 35°C) to the laboratory, where they were incubated for another 5 days at room temperature. The agar plates were examined under a stereomicroscope for the presence of tracks from moving larvae or free-living adults on the 3rd and 5th days. All microscopically positive dishes were further processed by washing the surface of the agar with a 10% formalin solution to collect worms for species identification. The differentiation of S. stercoralis larvae from hookworm larvae was performed under microscopic magnification of ϫ40. For QFEC, 2 g of individual fecal samples was weighed out and then stirred well in a vial containing a merthiolate-iodineformalin solution (2). The preserved stools were processed by QFEC (3). Briefly, the preserved fecal suspension was filtered through two layers of wet gauze into a centrifuge tube. The volume was adjusted to 10 ml with 10% formalin. Two milliliters of ethyl acetate was added, and the tube was closed and shaken for half a second. The stopper was removed, and the tube was centrifuged at 600 ϫ g for 10 min. The plug of debris along with the merthiolate-iodine-formalin solution was discarded by inverting the tube, leaving only the sediment, which was resuspended. The entire suspension was examined under a microscope. The total number of larvae in the sediment was counted and is presented as the number of larvae per gram of stool (lpg). A negative result meant that no larvae were seen in the whole sediment. This study protocol was approved by the Human Research Ethics Committee of Khon Kaen University.Of the 1,233 stool samples, 303 (24.57%) were found to be positive by at least one of the two meth...

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Evaluation of techniques for the diagnosis of Strongyloides stercoralis in human immunodeficiency virus (HIV) positive and HIV negative individuals in the city of Itajaí, Brazil

Abstract: Human immunodeficiency virus (HIV) and intestinal parasites are common in Brazil. Previous studies have shown that infection with

Cited by 50 publications

References 18 publications

Improved Diagnosis of Strongyloides stercoralis Using Recombinant Antigen-Based Serologies in a Community-Wide Study in Northern Argentina

Improved Diagnosis of Strongyloides stercoralis Using Recombinant Antigen-Based Serologies in a Community-Wide Study in Northern Argentina

Geohelminths distribution as affected by soil properties, physicochemical factors and climate in Sharkyia governorate Egypt

Comparison of the Quantitative Formalin Ethyl Acetate Concentration Technique and Agar Plate Culture for Diagnosis of Human Strongyloidiasis

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