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

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 mansoni-enzyme-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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High Incidence of Zika or Chikungunya Infection among Pregnant Women Hospitalized Due to Obstetrical Complications in Northeastern Brazil—Implications for Laboratory Screening in Arbovirus Endemic Area

Viruses ◽

10.3390/v13050744 ◽

2021 ◽

Vol 13 (5) ◽

pp. 744

Author(s):

Iracema J. A. A. Jacques ◽

Leila Katz ◽

Marília A. Sena ◽

Ana B. G. Guimarães ◽

Yasmim L. Silva ◽

...

Keyword(s):

Pregnant Women ◽

Clinical Data ◽

Obstetric Complications ◽

Northeastern Brazil ◽

Serological Tests ◽

Pregnancy And Childbirth ◽

Obstetrical Complications ◽

Risk Pregnancy ◽

Endemic Areas ◽

A Prospective Study

The diagnostic of arbovirus-related obstetric complications in high-risk pregnancy and childbirth care is challenging, especially in endemic areas. We conducted a prospective study to track active or recent Zika (ZIKV), dengue (DENV), or chikungunya (CHIKV) virus infection among hospitalized pregnant women (PW) with obstetric complications in a hospital at the epicenter of Zika outbreak and ZIKV-related microcephaly in Brazil. Clinical data and blood samples were collected at enrollment and 10 days after the admission of study participants, between October 2018 and May 2019. Further clinical data were extracted from medical records. Samples were screened by molecular and serological tests. Out of 780 participants, 93.1% (95% CI: 91.1–94.7%) presented previous DENV exposure (IgG). ZIKV, CHIKV, and/or DENV laboratory markers of recent or active infection were detected in 130 PW, yielding a prevalence of 16.6% (95% CI: 14.2–19.5%); 9.4% (95% CI: 7.4–11.7%), 7.4% (95% CI: 5.7–9.7%), and 0.38% (95% CI: 0.1–1.2%) of CHIKV, ZIKV, and DENV infections, respectively. Most ZIKV infections were detected by molecular assays (89.6%), while CHIKV infections were detected by serology (95.9%). Our findings highlight the need for arbovirus infections screening in PW with obstetrical complications, potentially associated to these infections in endemic areas regardless of the signs or symptoms suggestive of arboviral disease.

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Serodiagnosis of Louse-Borne Relapsing Fever with Glycerophosphodiester Phosphodiesterase (GlpQ) fromBorrelia recurrentis

Journal of Clinical Microbiology ◽

10.1128/jcm.38.10.3561-3571.2000 ◽

2000 ◽

Vol 38 (10) ◽

pp. 3561-3571 ◽

Cited By ~ 54

Author(s):

Stephen F. Porcella ◽

Sandra J. Raffel ◽

Merry E. Schrumpf ◽

Martin E. Schriefer ◽

David T. Dennis ◽

...

Keyword(s):

Serological Test ◽

Geometric Mean ◽

Eastern Africa ◽

Enzyme Linked Immunosorbent Assay ◽

Relapsing Fever ◽

Serum Samples ◽

Serological Tests ◽

Whole Cell ◽

Convalescent Phase ◽

Glycerophosphodiester Phosphodiesterase

Human louse-borne relapsing fever occurs in sporadic outbreaks in central and eastern Africa that are characterized by significant morbidity and mortality. Isolates of the causative agent,Borrelia recurrentis, were obtained from the blood of four patients during a recent epidemic of the disease in southern Sudan. TheglpQ gene, encoding glycerophosphodiester phosphodiesterase, from these isolates was sequenced and compared with the glpQ sequences obtained from other relapsing-fever spirochetes. Previously we showed that GlpQ of Borrelia hermsii is an immunogenic protein with utility as a serological test antigen for discriminating tick-borne relapsing fever from Lyme disease. In the present work, we cloned and expressed theglpQ gene from B. recurrentis and used recombinant GlpQ in serological tests. Acute- and convalescent-phase serum samples obtained from 42 patients with louse-borne relapsing fever were tested with an indirect immunofluorescence assay (IFA) and an enzyme-linked immunosorbent assay (ELISA) that used whole cells ofB. recurrentis and with immunoblotting to whole-cell lysates of the spirochete and Escherichia coli producing recombinant GlpQ. The geometric mean titers of the acute- and convalescent-phase serum samples measured by IFA were 1:83 and 1:575, respectively. The immunoblot analysis identified a high level of reactivity and seroconversion to GlpQ, and the assay was more sensitive than the whole-cell IFA and ELISA using purified, recombinant histidine-tagged GlpQ. Serum antibodies to GlpQ and other antigens persisted for 27 years in one patient. We conclude that assessment of anti-GlpQ antibodies will allow serological confirmation of louse-borne relapsing fever and determination of disease prevalence.

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Comparison between the efficiency of serological tests for Identification of Brucellosis

Baghdad Science Journal ◽

10.21123/bsj.7.2.901-909 ◽

2010 ◽

Vol 7 (2) ◽

pp. 901-909

Author(s):

Baghdad Science Journal

Keyword(s):

Rose Bengal ◽

Serological Test ◽

Elisa Test ◽

Health Centers ◽

Confirmatory Test ◽

Igg Antibodies ◽

Serological Tests ◽

Primary Screening ◽

Low Concentrations ◽

Immune Assay

Five serological methods for detection of Brucella were compaired in this study, Four of the methods are commonely used in the detections:- 1-Rose-Bengal: as primary screening test which depends on detecting antibodies in the blood serum. 2-IFAT: which detects IgG and IgM antibodies in the serum. 3-ELISA test: which detects IgG antibodies in the serum. 4-2ME test: which detects IgG antibodies The fifth methods. It was developed by a reasercher in one of the health centers in Baghdad. It was given the name of spot Immune Assay (SIA). Results declares that among (100) samples of patients blood, 76, 49, 49, 37, and 28. samples were positive to Rose Bengal, ELISA, SIA, 2ME and IFAT tests, respectively. When efficiency, sensitivity and specificity of the serological methods were compaired, the Following results were obtained: a) ELISA and SIA were superiors among the other confirming methods (2ME and IFAT) in detecting the highest cases (49 cases); 46 of them were from the (76) cases positive to Rose Bengal The confirmatory test 2ME was not efficient in detecting low concentrations of IgG antibodies when less than half (37) of the total positive cases (76) were detected by this test. b) IFAT test was the least efficient confirmatory test among all other test. c) As a new confirmatory test, SIA proved to be an efficient and serological test for Brucella detection in comparison with other tests. It is an easy to use test, rapid and could be performed without need to the expensive equipment .

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Bayesian evaluation of three serological tests for the diagnosis of bovine brucellosis in Bangladesh

Epidemiology and Infection ◽

10.1017/s0950268818003503 ◽

2019 ◽

Vol 147 ◽

Cited By ~ 5

Author(s):

A. K. M. A. Rahman ◽

S. Smit ◽

B. Devleesschauwer ◽

P. Kostoulas ◽

E. Abatih ◽

...

Keyword(s):

Latent Class ◽

Latent Class Model ◽

Dairy Farm ◽

Agglutination Test ◽

Enzyme Linked Immunosorbent Assay ◽

Bovine Brucellosis ◽

Class Model ◽

Serological Tests ◽

Predictive Values ◽

Conditional Dependence

AbstractWe evaluated the performance of three serological tests – an immunoglobulin G indirect enzyme linked immunosorbent assay (iELISA), a Rose Bengal test and a slow agglutination test (SAT) – for the diagnosis of bovine brucellosis in Bangladesh. Cattle sera (n = 1360) sourced from Mymensingh district (MD) and a Government owned dairy farm (GF) were tested in parallel. We used a Bayesian latent class model that adjusted for the conditional dependence among the three tests and assumed constant diagnostic accuracy of the three tests in both populations. The sensitivity and specificity of the three tests varied from 84.6% to 93.7%, respectively. The true prevalences of bovine brucellosis in MD and the GF were 0.6% and 20.4%, respectively. Parallel interpretation of iELISA and SAT yielded the highest negative predictive values: 99.9% in MD and 99.6% in the GF; whereas serial interpretation of both iELISA and SAT produced the highest positive predictive value (PPV): 99.9% in the GF and also high PPV (98.9%) in MD. We recommend the use of both iELISA and SAT together and serial interpretation for culling and parallel interpretation for import decisions. Removal of brucellosis positive cattle will contribute to the control of brucellosis as a public health risk in Bangladesh.

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Prevalence of asymptomatic SARS-CoV-2-positive individuals in the general population of northern Italy and evaluation of a diagnostic serological ELISA test: a cross-sectional study protocol

BMJ Open ◽

10.1136/bmjopen-2020-040036 ◽

2020 ◽

Vol 10 (10) ◽

pp. e040036

Author(s):

Massimo Guerriero ◽

Zeno Bisoffi ◽

Albino Poli ◽

Claudio Micheletto ◽

Carlo Pomari

Keyword(s):

General Population ◽

Study Protocol ◽

Latent Class ◽

Serological Test ◽

Statistical Technique ◽

Elisa Test ◽

Nasopharyngeal Swab ◽

Cross Sectional ◽

Predictive Values ◽

Study Results

IntroductionAs of 30 April 2020, the novel betacoronavirus SARS-CoV-2 had infected more than 3 172 000 individuals, killing over 224 000 people and spreading to more than 200 countries. Italy was the most affected country in Europe and the third most affected in the world in terms of the number of cases. Therefore, the aims of this study are: (1) to estimate the prevalence of asymptomatic SARS-CoV-2-positive individuals among the general population of Verona; (2) to assess the accuracy (sensitivity, specificity and predictive values) of an ELISA serological test for the screening of SARS-CoV-2.Methods and analysisThe study will be carried out on a random sample of subjects aged at least 10 years from the general population of Verona. Participants will undergo the measurement of vital parameters (oxygen saturation measured by oximeter, respiratory rate and body temperature detected by laser thermometer), the administration of a COVID-19-related symptoms questionnaire, the collection of a blood sample and a nasopharyngeal swab. Our evaluation will include the statistical technique of Latent Class Analysis, which will be the basis for the estimation of prevalence.Ethics and disseminationThe study protocol has been approved by the Ethics Committee of Verona and Rovigo provinces on 15 April 2020 (internal protocol number 2641CESC). The study results will be submitted for publication in international, peer-reviewed journals and the complete dataset will be deposited in a public repository. Most relevant data will be made available to policy-makers as well as disseminated to stakeholders and to the community.

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Evaluation of immunoglobulin G4 subclass antibody in a peptide-based enzyme-linked immunosorbent assay for the serodiagnosis of human fascioliasis

Parasitology ◽

10.1017/s0031182007003435 ◽

2007 ◽

Vol 134 (14) ◽

pp. 2021-2026 ◽

Cited By ~ 12

Author(s):

C. TANTRAWATPAN ◽

W. MALEEWONG ◽

C. WONGKHAM ◽

S. WONGKHAM ◽

P. M. INTAPAN ◽

...

Keyword(s):

Immunosorbent Assay ◽

Large Scale ◽

Laboratory Diagnosis ◽

Enzyme Linked Immunosorbent Assay ◽

Parasitic Infections ◽

Immunoglobulin G4 ◽

Predictive Values ◽

Diagnostic Potential ◽

Human Fascioliasis ◽

Specific Igg4

SUMMARYTo improve the diagnosis of human fascioliasis caused byFasciola gigantica, we developed a peptide-based enzyme-linked immunosorbent assay (peptide-based ELISA) based on the detection of specific IgG4 subclass antibody. Two identified B-cell epitopes ofF. giganticacathepsin L1 were synthesized as single synthetic peptides, acetyl-DKIDWRESGYVTELKDQGNC-carboxamide (peptide L) and acetyl-DKIDWRESGYVTEVKDQGNC-carboxamide (peptide V), and their diagnostic potential was evaluated. The sera of 25 patients infected withF. gigantica, 212 patients with other parasitic infections, 32 cholangiocarcinoma patients and 57 healthy controls were analysed. The sensitivity, specificity, accuracy, and positive and negative predictive values of this assay were the same with both peptides at 100%, 99·7%, 99·7%, 96·2% and 100%, respectively. These highly sensitive and specific peptide-based ELISAs for the detection of specific IgG4 antibody could be useful for laboratory diagnosis of human fascioliasis in future large-scale surveys throughout Southeast Asia where this disease is prevalent.

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Performance characteristics of a new automated method for measurement of anti-cyclic citrullinated peptide

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2014-0961 ◽

2015 ◽

Vol 53 (7) ◽

Author(s):

Madelon Noordegraaf ◽

Albert Wolthuis ◽

Frans Peters ◽

Monique de Groot ◽

Rein Hoedemakers

Keyword(s):

Clinical Manifestations ◽

Method Comparison ◽

Elisa Test ◽

Performance Characteristics ◽

Modular System ◽

Enzyme Linked Immunosorbent Assay ◽

Serological Tests ◽

Modular Systems ◽

Siemens Healthcare ◽

Automated Method

AbstractRheumatoid arthritis (RA) is a chronic inflammatory auto-immune disease affecting approximately 1%–2% of the population worldwide. RA is a potentially crippling disease since it results in malformation of the joints. RA is mostly diagnosed based on clinical manifestations but serological tests against autoantibodies, such as rheumatoid factor and anti-cyclic citrullinated peptides (aCCP), are available. The presence of aCCP antibodies is strongly associated with a more severe, destructive disease course. Recently, a new test for the measurement of aCCP antibodies on the IMMULITE 2000(XPi) platform was developed by Siemens Healthcare. In this study we investigated the performance characteristics of this new aCCP test in four different hospital laboratories and compared the new test with three different commercially available platforms.Samples were collected from patients presented to the hospital for aCCP measurement. Serum aCCP levels were determined by aCCP (Ig)G assay for IMMULITE 2000(XPi) systems (Siemens Healthcare), ImmunoScan RA enzyme-linked immunosorbent assay (ELISA) test (Eurodiagnostica), Immunocap 250 (Thermofisher) or aCCP IgG assay on the Modular system (Roche Diagnostics). The evaluation protocol consisted of within-run imprecision (20 sequential runs), between-run imprecision (16 workdays), comparison of serum and plasma measurement and method comparison.The within-run imprecision (n=20) for aCCP IgG assay on three different IMMULITE 2000(XPi) systems ranged from 3.0% to 6.9% at levels 3.2–171.2 U/mL. Between-run imprecision (n=16 days) ranged from 5.2% to 11% at levels of 3.2–106.9 U/mL. Method comparison showed good correlation when samples were measured on two different Immulite analyzers in two different hospital laboratories [0.21+0.96x (n=40)]. Method comparison of the IMMULITE 2000(XPi) aCCP test with aCCP on Immunoscan RA ELISA (n=112), Immunocap 250 (n=105) and the Modular system (n=289) resulted in a concordance of 90.2%, 93.3% and 94.8%, respectively. Correlation of serum versus heparin samples showed a correlation of 0.12+1.08x for the Immulite 2000(XPi) test.The aCCP assay on the IMMULITE 2000(XPi) has good performance characteristics and shows high level of concordance with the aCCP test on Immunoscan RA ELISA test, Immunocap 250 and the Modular systems.

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Performance of Ag-ELISA in the diagnosis of Taenia solium cysticercosis in naturally infected pigs in Tanzania

Parasites & Vectors ◽

10.1186/s13071-020-04416-4 ◽

2020 ◽

Vol 13 (1) ◽

Author(s):

Mwemezi L. Kabululu ◽

Maria V. Johansen ◽

James E. D. Mlangwa ◽

Ernatus M. Mkupasi ◽

Uffe C. Braae ◽

...

Keyword(s):

Test Performance ◽

Late Onset ◽

Taenia Solium ◽

Elisa Test ◽

Diagnostic Tools ◽

Enzyme Linked Immunosorbent Assay ◽

Likelihood Ratios ◽

Taenia Hydatigena ◽

Predictive Values ◽

Circulating Antigens

Abstract Background Taenia solium is a zoonotic parasite responsible for neurocysticercosis—a major cause of late-onset acquired epilepsy in humans. Lack of affordable, specific and sensitive diagnostic tools hampers control of the parasite. This study assessed the performance of an antigen detection enzyme-linked immunosorbent assay (Ag-ELISA) in the diagnosis of viable T. solium cysticercosis in naturally infected slaughter-age pigs in an endemic area in Tanzania. Methods A total of 350 pigs were bled before they were slaughtered and their carcases examined. Serum was analyzed for circulating antigens by using a monoclonal antibody-based B158/B60 Ag-ELISA. Each carcase was examined for the presence of Taenia hydatigena cysticerci and half carcase musculature together with the whole brain, head muscles, tongue, heart and diaphragm were sliced with fine cuts (< 0.5 cm) to reveal and enumerate T. solium cysticerci. Half carcase dissection can detect at least 84% of infected pigs. Prevalence and their 95% confidence intervals (CI) were calculated in Stata 12. Sensitivity, specificity, predictive values and likelihood ratios were determined. Results Twenty–nine pigs (8.3%, 95% CI: 5.6–11.7%) had viable T. solium cysticerci while 11 pigs had T. hydatigena cysticerci (3.1%, 95% CI: 1.6–5.5%). No co-infection was observed. Sixty-eight pigs (19.4%, 95% CI: 15.4–20%) tested positive on Ag-ELISA; of these, 24 had T. solium cysticerci and 7 had T. hydatigena cysticerci. Sensitivity and specificity were determined to be 82.7% and 86.3%, respectively. Positive and negative predictive values were 35.2% and 98.2%, respectively. Likelihood ratios for positive and negative Ag-ELISA test results were 6.0 and 0.2, respectively. There was a significant positive correlation between the titre of circulating antigens and intensity of T. solium cysticerci (r(348) = 0.63, P < 0.001). Conclusions The Ag-ELISA test characteristics reported in this study indicate that the test is more reliable in ruling out T. solium cysticercosis in pigs, than in confirming it. Hence, a negative result will almost certainly indicate that a pig has no infection, but a positive result should always be interpreted with caution. Estimates of T. solium prevalence based on Ag-ELISA results should, therefore, be adjusted for test performance characteristics and occurrence of T. hydatigena.

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Studies on the Feeding Habits ofLutzomyia (Lutzomyia) longipalpis(Lutz & Neiva, 1912) (Diptera: Psychodidae: Phlebotominae) Populations from Endemic Areas of American Visceral Leishmaniasis in Northeastern Brazil

Journal of Tropical Medicine ◽

10.1155/2012/858657 ◽

2012 ◽

Vol 2012 ◽

pp. 1-5 ◽

Cited By ~ 28

Author(s):

Margarete Martins dos Santos Afonso ◽

Rosemere Duarte ◽

José Carlos Miranda ◽

Lindenbergh Caranha ◽

Elizabeth Ferreira Rangel

Keyword(s):

Visceral Leishmaniasis ◽

Feeding Habits ◽

Blood Feeding ◽

Northeastern Brazil ◽

Sand Fly ◽

Lutzomyia Longipalpis ◽

Elisa Technique ◽

Endemic Areas ◽

Feeding Sources

The aim of this study was to identify potential blood feeding sources ofL. (L.) longipalpisspecimens from populations in Northeastern Brazil, endemic areas of American Visceral Leishmaniasis (AVL) and its correlation with the transmission ofL. (L.) i. chagasi. The ELISA technique was applied using bird, dog, goat, opossum, equine, feline, human, sheep, and rodent antisera to analyze 609 females, resulting in an overall positivity of 60%. In all municipalities, females showed higher positivity for bird followed by dog antiserum and sand fly specimens were also positive for equine, feline, human, sheep, goat, opossum, and rodent antisera. The finding for 17 combinations of two or three types of blood in some females corroborates the opportunistic habit of this sand fly species. The results demonstrating the association betweenL. (L.) longipalpisand opossum suggest the need for further evaluation of the real role of this synanthropic mammal in the eco-epidemiology of AVL.

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Enzyme-linked immunosorbent assay (ELISA) immunoassaying versus microscopy: advantages and drawbacks for diagnosing giardiasis

Sao Paulo Medical Journal ◽

10.1590/s1516-31802005000600006 ◽

2005 ◽

Vol 123 (6) ◽

pp. 282-285 ◽

Cited By ~ 13

Author(s):

Alaíde Mader Braga Vidal ◽

Wilson Roberto Catapani

Keyword(s):

Microscopic Examination ◽

Giardia Lamblia ◽

Specific Antigen ◽

Significant Proportion ◽

High Sensitivity ◽

Laboratory Diagnosis ◽

Elisa Test ◽

Enzyme Linked Immunosorbent Assay ◽

Double Blind Study ◽

Double Blind

CONTEXT AND OBJECTIVE: Giardiasis is common in Brazil. For laboratory diagnosis, the method most utilized is microscopic examination of fecal samples, but the immunoenzymatic method is also available. The aim of this work was to verify the advantages and drawbacks of immunoassaying versus microscopy for diagnosing Giardia lamblia, when a single fecal sample is analyzed. DESIGN AND SETTING: Prospective, double-blind study at the parasitology laboratory of Faculdade de Medicina da Fundação ABC. METHODS: Samples were prepared according to the traditional sedimentation (Hoffman, Pons and Janer) and Faust methods. Results were deemed positive when Giardia lamblia was found by one or both methods. The Prospect ELISA kit was used for detecting Giardia lamblia-specific antigen, in accordance with the manufacturer's instructions. Results were expressed on a visual scale as negative or positive (+, ++, +++ or ++++). RESULTS: The ELISA test was positive even when a significant proportion of corresponding samples examined by microscopy were negative. This trend was statistically significant (p < 0.001). The overall concordance of results between the ELISA test and microscopic examination of single samples was only moderate (0.50 by kappa test). CONCLUSION: The ELISA test is useful when just searching for Giardia lamblia, because of its high sensitivity. For daily practice, we recommend microscopy, which is much cheaper and can also detect other parasites. The low positivity of single samples in this method can be overcome by using three samples, as recommended by most authors.

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