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Vikas S, Duggal N. An observational study to compare the diagnostic accuracy of rapid antigen test and rapid antibody tests in various periods of enteric fever. Trop Doct 2022; 52:311-314. [DOI: 10.1177/00494755221074538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A cross-sectional observational study was done on 180 fever patients to assess the diagnostic accuracy of rapid serological tests in early detection (<5 days of fever) of S. typhi and S. paratyphi in comparison to blood culture and Widal test Blood culture was positive in 58 (32.22%) cases. The diagnostic accuracy (<5 days of fever) of rapid antigen test, rapid antibody test, and Widal test was 45.56%, 42.22%, and 41.11% (p = 0.675) while sensitivity was 68.97%, 48.28%, and 46.55%, respectively. In conclusion, rapid antigen test holds moderately higher sensitivity in the first five days of fever as compared to rapid antibody and Widal tests. It is recommended that the antigen detection tests should be used for screening enteric fever in the first week of presentation.
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Affiliation(s)
- Saini Vikas
- University College Of Medical Sciences And Guru Teg Bahadur Hospital, Delhi, India
| | - Nandini Duggal
- Atal Bihari Vajpayee Institute of Medical Sciences (ABVIMS) and Dr RML Hospital, New Delhi, India
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Arora P, Thorlund K, Brenner DR, Andrews JR. Comparative accuracy of typhoid diagnostic tools: A Bayesian latent-class network analysis. PLoS Negl Trop Dis 2019; 13:e0007303. [PMID: 31067228 PMCID: PMC6527309 DOI: 10.1371/journal.pntd.0007303] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 05/20/2019] [Accepted: 03/13/2019] [Indexed: 11/19/2022] Open
Abstract
Background Typhoid fevers are infections caused by the bacteria Salmonella enterica serovar Typhi (Salmonella Typhi) and Paratyphi A, B and C (Salmonella Paratyphi). Approximately 17.8 million incident cases of typhoid fever occur annually, and incidence is highest in children. The accuracy of current diagnostic tests of typhoid fever is poorly understood. We aimed to determine the comparative accuracy of available tests for the pediatric population. Methods We first conducted a systematic literature review to identify studies that compared diagnostic tests for typhoid fever in children (aged ≤15 years) to blood culture results. We applied a Bayesian latent-class extension to a network meta-analysis model. We modelled known diagnostic properties of bone marrow culture and the relationship between bone marrow and blood culture as informative priors in a Bayesian framework. We tested sensitivities for the proportion of negative blood samples that were false as well as bone marrow sensitivity and specificity. Results We found 510 comparisons from 196 studies and 57 specific to the pediatric population. IgM-based tests outperformed their IgG-based counterparts for ELISA and Typhidot tests. The lateral flow IgG test performed comparatively well with 92% sensitivity (72% to 98% across scenario analyses) and 94% specificity. The most sensitive test of those investigated for the South Asian pediatric population was the Reverse Passive Hemagglutination Assay with 99% sensitivity (98% - 100% across scenario analyses). Adding a Widal slide test to other typhoid diagnostics did not substantially improve diagnostic performance beyond the single test alone, however, a lateral flow-based IgG rapid test combined with the typhoid/paratyphoid (TPT) assay yielded improvements in sensitivity without substantial declines in specificity and was the best performing combination test in this setting. Conclusion In the pediatric population, lateral-flow IgG, TPT and Reverse Passive Hemagglutination tests had high diagnostic accuracy compared to other diagnostics. Combinations of tests may provide a feasible option to increase diagnostic sensitivity. South Asia has the most informed set of data on typhoid diagnostic testing accuracy, and the evidence base in other important regions needs to be expanded. Typhoid fever is an infection caused by the bacterium Salmonella Typhi. Typhoid fever is rare in developed countries but remains high in the developing world. Effective treatment is available but accurate diagnosis of typhoid fever is challenging as typhoid fever can be difficult to distinguish from other infections. Bone marrow culture is the most accurate diagnostic test for typhoid fever however is invasive and not feasible in many settings. New vaccines for typhoid and the need for improved estimates of burden increases the demand for improved understanding of diagnostic accuracy. Comparing the diagnostic accuracy of tests for typhoid fever is challenging as head-to-head studies are few. We applied newly developed methods for comparative evaluation of diagnostic tests for typhoid fever in children using statistical approaches that allowed for the proper incorporation of uncertainty and comparison of tests that had not been compared directly. The lateral-flow IgG, TPT and Reverse Passive Hemagglutination tests all had good diagnostic accuracy compared to other diagnostics. Combinations of tests may provide a feasible option to increase diagnostic sensitivity. Finally, while South Asia has the most informed set of data on typhoid diagnostic testing accuracy, the evidence base in other important regions needs to be expanded.
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Affiliation(s)
- Paul Arora
- Dalla Lana School of Public Health, Division of Epidemiology, University of Toronto, Ontario, Canada
- * E-mail:
| | - Kristian Thorlund
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontario, Canada
| | - Darren R. Brenner
- Departments of Oncology and Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Jason R. Andrews
- Division of Infectious Diseases and Geographic Medicine, Stanford University, Stanford, California, United States of America
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Development of Inhouse Immunoblot Method for Detection of Anti Salmonella Antibody and Comparison with Widal Test. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2018. [DOI: 10.22207/jpam.12.3.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Abstract
BACKGROUND Differentiating both typhoid (Salmonella Typhi) and paratyphoid (Salmonella Paratyphi A) infection from other causes of fever in endemic areas is a diagnostic challenge. Although commercial point-of-care rapid diagnostic tests (RDTs) for enteric fever are available as alternatives to the current reference standard test of blood or bone marrow culture, or to the widely used Widal Test, their diagnostic accuracy is unclear. If accurate, they could potentially replace blood culture as the World Health Organization (WHO)-recommended main diagnostic test for enteric fever. OBJECTIVES To assess the diagnostic accuracy of commercially available rapid diagnostic tests (RDTs) and prototypes for detecting Salmonella Typhi or Paratyphi A infection in symptomatic persons living in endemic areas. SEARCH METHODS We searched the Cochrane Infectious Diseases Group Specialized Register, MEDLINE, Embase, Science Citation Index, IndMED, African Index Medicus, LILACS, ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) up to 4 March 2016. We manually searched WHO reports, and papers from international conferences on Salmonella infections. We also contacted test manufacturers to identify studies. SELECTION CRITERIA We included diagnostic accuracy studies of enteric fever RDTs in patients with fever or with symptoms suggestive of enteric fever living in endemic areas. We classified the reference standard used as either Grade 1 (result from a blood culture and a bone marrow culture) or Grade 2 (result from blood culture and blood polymerase chain reaction, or from blood culture alone). DATA COLLECTION AND ANALYSIS Two review authors independently extracted the test result data. We used a modified QUADAS-2 extraction form to assess methodological quality. We performed a meta-analysis when there were sufficient studies for the test and heterogeneity was reasonable. MAIN RESULTS Thirty-seven studies met the inclusion criteria and included a total of 5080 participants (range 50 to 1732). Enteric fever prevalence rates in the study populations ranged from 1% to 75% (median prevalence 24%, interquartile range (IQR) 11% to 46%). The included studies evaluated 16 different RDTs, and 16 studies compared two or more different RDTs. Only three studies used the Grade 1 reference standard, and only 11 studies recruited unselected febrile patients. Most included studies were from Asia, with five studies from sub-Saharan Africa. All of the RDTs were designed to detect S.Typhi infection only.Most studies evaluated three RDTs and their variants: TUBEX in 14 studies; Typhidot (Typhidot, Typhidot-M, and TyphiRapid-Tr02) in 22 studies; and the Test-It Typhoid immunochromatographic lateral flow assay, and its earlier prototypes (dipstick, latex agglutination) developed by the Royal Tropical Institute, Amsterdam (KIT) in nine studies. Meta-analyses showed an average sensitivity of 78% (95% confidence interval (CI) 71% to 85%) and specificity of 87% (95% CI 82% to 91%) for TUBEX; and an average sensitivity of 69% (95% CI 59% to 78%) and specificity of 90% (95% CI 78% to 93%) for all Test-It Typhoid and prototype tests (KIT). Across all forms of the Typhidot test, the average sensitivity was 84% (95% CI 73% to 91%) and specificity was 79% (95% CI 70% to 87%). When we based the analysis on the 13 studies of the Typhidot test that either reported indeterminate test results or where the test format means there are no indeterminate results, the average sensitivity was 78% (95% CI 65% to 87%) and specificity was 77% (95% CI 66% to 86%). We did not identify any difference in either sensitivity or specificity between TUBEX, Typhidot, and Test-it Typhoid tests when based on comparison to the 13 Typhidot studies where indeterminate results are either reported or not applicable. If TUBEX and Test-it Typhoid are compared to all Typhidot studies, the sensitivity of Typhidot was higher than Test-it Typhoid (15% (95% CI 2% to 28%), but other comparisons did not show a difference at the 95% level of CIs.In a hypothetical cohort of 1000 patients presenting with fever where 30% (300 patients) have enteric fever, on average Typhidot tests reporting indeterminate results or where tests do not produce indeterminate results will miss the diagnosis in 66 patients with enteric fever, TUBEX will miss 66, and Test-It Typhoid and prototype (KIT) tests will miss 93. In the 700 people without enteric fever, the number of people incorrectly diagnosed with enteric fever would be 161 with Typhidot tests, 91 with TUBEX, and 70 with Test-It Typhoid and prototype (KIT) tests. The CIs around these estimates were wide, with no difference in false positive results shown between tests.The quality of the data for each study was evaluated using a standardized checklist called QUADAS-2. Overall, the certainty of the evidence in the studies that evaluated enteric fever RDTs was low. AUTHORS' CONCLUSIONS In 37 studies that evaluated the diagnostic accuracy of RDTs for enteric fever, few studies were at a low risk of bias. The three main RDT tests and variants had moderate diagnostic accuracy. There was no evidence of a difference between the average sensitivity and specificity of the three main RDT tests. More robust evaluations of alternative RDTs for enteric fever are needed.
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Affiliation(s)
- Lalith Wijedoru
- Liverpool School of Tropical MedicineDepartment of Clinical SciencesLiverpoolUKL3 5QA
| | - Sue Mallett
- University of BirminghamInstitute of Applied Health SciencesEdgbastonBirminghamUKB15 2TT
| | - Christopher M Parry
- Liverpool School of Tropical MedicineDepartment of Clinical SciencesLiverpoolUKL3 5QA
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Storey HL, Huang Y, Crudder C, Golden A, de los Santos T, Hawkins K. A Meta-Analysis of Typhoid Diagnostic Accuracy Studies: A Recommendation to Adopt a Standardized Composite Reference. PLoS One 2015; 10:e0142364. [PMID: 26566275 PMCID: PMC4643909 DOI: 10.1371/journal.pone.0142364] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 10/21/2015] [Indexed: 01/09/2023] Open
Abstract
Novel typhoid diagnostics currently under development have the potential to improve clinical care, surveillance, and the disease burden estimates that support vaccine introduction. Blood culture is most often used as the reference method to evaluate the accuracy of new typhoid tests; however, it is recognized to be an imperfect gold standard. If no single gold standard test exists, use of a composite reference standard (CRS) can improve estimation of diagnostic accuracy. Numerous studies have used a CRS to evaluate new typhoid diagnostics; however, there is no consensus on an appropriate CRS. In order to evaluate existing tests for use as a reference test or inclusion in a CRS, we performed a systematic review of the typhoid literature to include all index/reference test combinations observed. We described the landscape of comparisons performed, showed results of a meta-analysis on the accuracy of the more common combinations, and evaluated sources of variability based on study quality. This wide-ranging meta-analysis suggests that no single test has sufficiently good performance but some existing diagnostics may be useful as part of a CRS. Additionally, based on findings from the meta-analysis and a constructed numerical example demonstrating the use of CRS, we proposed necessary criteria and potential components of a typhoid CRS to guide future recommendations. Agreement and adoption by all investigators of a standardized CRS is requisite, and would improve comparison of new diagnostics across independent studies, leading to the identification of a better reference test and improved confidence in prevalence estimates.
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Affiliation(s)
- Helen L. Storey
- Diagnostics Program, PATH, Seattle, Washington, United States of America
- * E-mail:
| | - Ying Huang
- Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Chris Crudder
- Diagnostics Program, PATH, Seattle, Washington, United States of America
| | - Allison Golden
- Diagnostics Program, PATH, Seattle, Washington, United States of America
| | - Tala de los Santos
- Diagnostics Program, PATH, Seattle, Washington, United States of America
| | - Kenneth Hawkins
- Diagnostics Program, PATH, Seattle, Washington, United States of America
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Typhoid fever in young children in Bangladesh: clinical findings, antibiotic susceptibility pattern and immune responses. PLoS Negl Trop Dis 2015; 9:e0003619. [PMID: 25849611 PMCID: PMC4388457 DOI: 10.1371/journal.pntd.0003619] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 02/12/2015] [Indexed: 12/26/2022] Open
Abstract
Background Children bear a large burden of typhoid fever caused by Salmonella enterica serotype Typhi (S. Typhi) in endemic areas. However, immune responses and clinical findings in children are not well defined. Here, we describe clinical and immunological characteristics of young children with S. Typhi bacteremia, and antimicrobial susceptibility patterns of isolated strains. Methods As a marker of recent infection, we have previously characterized antibody-in-lymphocyte secretion (TPTest) during acute typhoid fever in adults. We similarly assessed membrane preparation (MP) IgA responses in young children at clinical presentation, and then 7-10 days and 21-28 days later. We also assessed plasma IgA, IgG and IgM responses and T cell proliferation responses to MP at these time points. We compared responses in young children (1-5 years) with those seen in older children (6-17 years), adults (18-59 years), and age-matched healthy controls. Principal Findings We found that, compared to age-matched controls patients in all age cohorts had significantly more MP-IgA responses in lymphocyte secretion at clinical presentation, and the values fell in all groups by late convalescence. Similarly, plasma IgA responses in patients were elevated at presentation compared to controls, with acute and convalescent IgA and IgG responses being highest in adults. T cell proliferative responses increased in all age cohorts by late convalescence. Clinical characteristics were similar in all age cohorts, although younger children were more likely to present with loss of appetite, less likely to complain of headache compared to older cohorts, and adults were more likely to have ingested antibiotics. Multi-drug resistant strains were present in approximately 15% of each age cohort, and 97% strains had resistance to nalidixic acid. Conclusions This study demonstrates that S. Typhi bacteremia is associated with comparable clinical courses, immunologic responses in various age cohorts, including in young children, and that TPTest can be used as marker of recent typhoid fever, even in young children. The highest disease burden of typhoid fever caused by Salmonella enterica serotype Typhi (S. Typhi) is seen in children under five years of age in endemic areas. We investigated both mucosal and systemic immune responses in S. Typhi bacteremic young children (aged, 1 to 5 years) by measuring S. Typhi membrane preparation (MP) specific IgA response in lymphocyte culture secretion and plasma IgA, IgG and IgM responses using ELISA. We also measured T cell proliferation responses using 3H-thymidine incorporation assay. We compared the responses to S. Typhi bacteremic older children (6 to 17 years) and adults (18 to 59 years) and with age-matched healthy controls (HC). Younger children, older children and adults show comparable responses in lymphocyte secretions after onset of illness. Plasma antibody responses to MP vary between young children and other age groups. T cell proliferative responses increased in all age cohorts by late convalescence. Clinical characteristics were similar in all age cohorts. Emergence of MDR S. Typhi strains is seen in young children which does not impact on the clinical symptoms or the immune responses. The results of this study show that natural infections do induce immune response in young children as well as in adults.
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Lalremruata R, Chadha S, Bhalla P. Retrospective audit of the widal test for diagnosis of typhoid Fever in pediatric patients in an endemic region. J Clin Diagn Res 2014; 8:DC22-5. [PMID: 24995178 DOI: 10.7860/jcdr/2014/7819.4373] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2013] [Accepted: 03/10/2014] [Indexed: 11/24/2022]
Abstract
INTRODUCTION Although typhoid fever is confirmed by culture of Salmonella Typhi, Widal test is widely used in India but little information exists about its reliability. MATERIALS AND METHODS We examined the performance of Widal test in our hospital for diagnosis of typhoid fever in children. Hundred consecutive pediatric in-patients for whom, the Widal test was requested were grouped into four categories: widal positive and clinically consistent with typhoid fever (Group 1; n=42), widal negative but clinically consistent (Group 2, n=12), widal positive but not clinically consistent (Group 3, n=12) and widal negative and also not clinically consistent (Group 4, n=34). The results were analyzed by the test performance criteria, namely, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) using culture-confirmed typhoid fever cases as the "true positives". RESULTS We found that 7/100 patients had culture-proven typhoid fever. Using a cut off ≥ 50 for O agglutinins or ≥100 for H agglutinins, the Widal test gave a sensitivity of 71.43%, specificity of 47.31%, and a positive predictive value of 09.25% and a negative predictive value of 95.65%. CONCLUSION The Widal test is an easy, inexpensive and relatively non-invasive but is not reliable in our set up because of a low PPV. There is a need for a more efficient rapid diagnostic test for typhoid fever.
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Affiliation(s)
- Ralte Lalremruata
- Student, Department of Microbiology, Maulana Azad Medical College , New Delhi, India
| | - Sanjim Chadha
- Senior Resident, Department of Microbiology Maulana Azad Medical College , New Delhi, India
| | - Preena Bhalla
- Director Professor, Department of Microbiology, Maulana Azad Medical College , New Delhi, India
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Khanam F, Sheikh A, Sayeed MA, Bhuiyan MS, Choudhury FK, Salma U, Pervin S, Sultana T, Ahmed D, Goswami D, Hossain ML, Mamun KZ, Charles RC, Brooks WA, Calderwood SB, Cravioto A, Ryan ET, Qadri F. Evaluation of a typhoid/paratyphoid diagnostic assay (TPTest) detecting anti-Salmonella IgA in secretions of peripheral blood lymphocytes in patients in Dhaka, Bangladesh. PLoS Negl Trop Dis 2013; 7:e2316. [PMID: 23951368 PMCID: PMC3708850 DOI: 10.1371/journal.pntd.0002316] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2013] [Accepted: 06/03/2013] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Rapid and reliable diagnostic assays for enteric (typhoid and paratyphoid) fever are urgently needed. We report the characterization of novel approach utilizing lymphocyte secretions, for diagnosing patients with enteric fever by the TPTest procedure. METHODOLOGY TPTest detects Salmonella-specific IgA responses in lymphocyte culture supernatant. We utilized TPTest in patients with suspected enteric fever, patients with other illnesses, and healthy controls. We also evaluated simplified modifications of TPTest for adaptation in laboratories with limited facilities and equipment. PRINCIPAL FINDINGS TPTest was positive in 39 (27 typhoid and 12 paratyphoid A) patients confirmed by blood culture and was negative in 74 healthy individuals. Among 32 individuals with other illnesses, 29 were negative by TPTest. Of 204 individuals with suspected enteric fever who were negative by blood culture, 44 were positive by TPTest and the patients were clinically indistinguishable from patients with confirmed bacteremia, except they were more likely to be under 5 years of age. We evaluated simplifications in TPTest, including showing that lymphocytes could be recovered using lysis buffer or buffy coat method as opposed to centrifugation, that incubation of cells at 37°C did not require supplemental CO2, and that results were available for majority of samples within 24 hours. Positive results by TPTest are transient and revert to negative during convalescence, supporting use of the test in endemic areas. The results can also be read using immunodot blot approach as opposed to ELISA. Since no true gold standard currently exists, we used a number of definitions of true positives and negatives. TPTest had sensitivity of 100% compared to blood culture, and specificity that ranged from 78-97% (73-100, 95% CI), depending on definition of true negative. CONCLUSION The TPTest is useful for identification of patients with enteric fever in an endemic area, and additional development of simplified TPTest is warranted.
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Affiliation(s)
- Farhana Khanam
- International Centre for Diarrhoeal Disease Research (icddr,b), Bangladesh, Dhaka, Bangladesh
| | - Alaullah Sheikh
- International Centre for Diarrhoeal Disease Research (icddr,b), Bangladesh, Dhaka, Bangladesh
| | - Md. Abu Sayeed
- International Centre for Diarrhoeal Disease Research (icddr,b), Bangladesh, Dhaka, Bangladesh
| | - Md. Saruar Bhuiyan
- International Centre for Diarrhoeal Disease Research (icddr,b), Bangladesh, Dhaka, Bangladesh
| | - Feroza Kaneez Choudhury
- International Centre for Diarrhoeal Disease Research (icddr,b), Bangladesh, Dhaka, Bangladesh
| | - Umme Salma
- International Centre for Diarrhoeal Disease Research (icddr,b), Bangladesh, Dhaka, Bangladesh
| | - Shahnaz Pervin
- Department of Microbiology, Dhaka Medical College and Hospital (DMCH), Dhaka, Bangladesh
| | - Tania Sultana
- International Centre for Diarrhoeal Disease Research (icddr,b), Bangladesh, Dhaka, Bangladesh
| | - Dilruba Ahmed
- International Centre for Diarrhoeal Disease Research (icddr,b), Bangladesh, Dhaka, Bangladesh
| | - Doli Goswami
- International Centre for Diarrhoeal Disease Research (icddr,b), Bangladesh, Dhaka, Bangladesh
| | - Md. Lokman Hossain
- International Centre for Diarrhoeal Disease Research (icddr,b), Bangladesh, Dhaka, Bangladesh
| | - K. Z. Mamun
- Department of Microbiology, Dhaka Medical College and Hospital (DMCH), Dhaka, Bangladesh
| | - Richelle C. Charles
- Division of Infectious Disease, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - W. Abdullah Brooks
- International Centre for Diarrhoeal Disease Research (icddr,b), Bangladesh, Dhaka, Bangladesh
| | - Stephen B. Calderwood
- Division of Infectious Disease, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | | | - Edward T. Ryan
- Division of Infectious Disease, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Firdausi Qadri
- International Centre for Diarrhoeal Disease Research (icddr,b), Bangladesh, Dhaka, Bangladesh
- * E-mail:
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Salmonella enterica serovar Typhi-specific immunoglobulin A antibody responses in plasma and antibody in lymphocyte supernatant specimens in Bangladeshi patients with suspected typhoid fever. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2009; 16:1587-94. [PMID: 19741090 DOI: 10.1128/cvi.00311-09] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Many currently available diagnostic tests for typhoid fever lack sensitivity and/or specificity, especially in areas of the world where the disease is endemic. In order to identify a diagnostic test that better correlates with typhoid fever, we evaluated immune responses to Salmonella enterica serovar Typhi (serovar Typhi) in individuals with suspected typhoid fever in Dhaka, Bangladesh. We enrolled 112 individuals with suspected typhoid fever, cultured day 0 blood for serovar Typhi organisms, and performed Widal assays on days 0, 5, and 20. We harvested peripheral blood lymphocytes and analyzed antibody levels in supernatants collected on days 0, 5, and 20 (using an antibody-in-lymphocyte-supernatant [ALS] assay), as well as in plasma on these days. We measured ALS reactivity to a serovar Typhi membrane preparation (MP), a formalin-inactivated whole-cell preparation, and serovar Typhi lipopolysaccharide. We measured responses in healthy Bangladeshi, as well as in Bangladeshi febrile patients with confirmed dengue fever or leptospirosis. We categorized suspected typhoid fever individuals into different groups (groups I to V) based on blood culture results, Widal titer, and clinical features. Responses to MP antigen in the immunoglobulin A isotype were detectable at the time of presentation in the plasma of 81% of patients. The ALS assay, however, tested positive in all patients with documented or highly suspicious typhoid, suggesting that such a response could be the basis of improved diagnostic point-of-care-assay for serovar Typhi infection. It can be important for use in epidemiological studies, as well as in difficult cases involving fevers of unknown origin.
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Abdoel TH, Pastoor R, Smits HL, Hatta M. Laboratory evaluation of a simple and rapid latex agglutination assay for the serodiagnosis of typhoid fever. Trans R Soc Trop Med Hyg 2007; 101:1032-8. [PMID: 17673269 DOI: 10.1016/j.trstmh.2007.05.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2006] [Revised: 05/30/2007] [Accepted: 05/30/2007] [Indexed: 10/23/2022] Open
Abstract
A latex agglutination assay for the serodiagnosis of typhoid fever was evaluated on samples collected from patients with clinical suspicion of typhoid fever in South Sulawesi, Indonesia, where the disease is endemic. The latex assay is very easy to use, gives a rapid result and may be used as a point-of-care diagnostic test. For acute phase samples collected on average 6 days after the onset of illness, the sensitivity is 42.5% for culture-confirmed patients with typhoid fever and the specificity is 96.9%. The sensitivity improved with the duration of illness from 30.8% for samples collected during the first 4-5 days of illness to 45.5% for samples collected between days 7 and 9, and to 84.6% for the samples collected more than 9 days after the onset of illness. Testing of follow-up samples may further improve sensitivity by demonstrating seroconversion.
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Affiliation(s)
- Theresia H Abdoel
- KIT Biomedical Research, Royal Tropical Institute/Koninklijk Instituut voor de Tropen (KIT), Meibergdreef 39, 1105 AZ Amsterdam, The Netherlands
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Dimitrov T, Udo EE, Albaksami O, Al-Shehab S, Kilani A, Shehab M, Al-Nakkas A. Clinical and microbiological investigations of typhoid fever in an infectious disease hospital in Kuwait. J Med Microbiol 2007; 56:538-544. [PMID: 17374897 DOI: 10.1099/jmm.0.46814-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A retrospective analysis of 135 typhoid cases was conducted to review the clinical, epidemiological and microbiological characteristics of enteric fever cases diagnosed and treated at the Infectious Diseases Hospital, Kuwait, from 2002 to 2005. Diagnosis of patients was based on clinical features, serology and blood culture. The susceptibility testing of the isolates to ampicillin, chloramphenicol, trimethoprim–sulfamethoxazole, ceftriaxone, ciprofloxacin and nalidixic acid was performed by the disc diffusion method, and MICs of ceftriaxone and ciprofloxacin were determined by Etest. Of 135 typhoid fever patients, 108 (88 %) were treated with ceftriaxone and 27 (20 %) were treated with ciprofloxacin. The mean time for fever defervescence with ciprofloxacin therapy was 8 days and 6.3 days for those treated with ceftriaxone. Of the 135 Salmonella enterica serotypes Typhi and Paratyphi A isolated from patients, 50 (37 %) were multidrug resistant (MDR) and 94 (69.6 %) isolates of both serotypes were nalidixic acid resistant (NAR). Between 90 and 100 % of MDR and NAR strains had decreased susceptibility to ciprofloxacin (0.125–1 μg ml−1). Low-level resistance to ciprofloxacin (MIC 0.125−1 μg ml−1) was also detected in 13.8 and 33.3 % of nalidixic acid-susceptible isolates of S. Typhi and S. Paratyphi A, respectively. All isolates were susceptible to ceftriaxone. Two relapses occurred in the ciprofloxacin-treated group. MDR strains and strains resistant to ciprofloxacin and ceftriaxone are a major threat in the developing world. A situation is fast approaching where the emergence of highly resistant Salmonella isolates is quite likely. Proper steps must be taken to avoid a pandemic spread of MDR S. Typhi strains.
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Affiliation(s)
- Tsonyo Dimitrov
- Department of Medical Laboratories, Microbiology Section, Infectious Diseases Hospital, PO Box 4710, Safat 13048, Kuwait
| | - Eded E Udo
- Department of Microbiology, Faculty of Medicine, Kuwait University, PO Box 14923, Safat 13110, Kuwait
| | - Ossama Albaksami
- Department of Pediatrics, Infectious Diseases Hospital, PO Box 4710, Safat 13048, Kuwait
| | - Shehab Al-Shehab
- Department of Medicine, Infectious Diseases Hospital, PO Box 4710, Safat 13048, Kuwait
| | - Abdal Kilani
- Department of Medicine, Infectious Diseases Hospital, PO Box 4710, Safat 13048, Kuwait
| | - Medhat Shehab
- Department of Medicine, Infectious Diseases Hospital, PO Box 4710, Safat 13048, Kuwait
| | - Aref Al-Nakkas
- Department of Medicine, Infectious Diseases Hospital, PO Box 4710, Safat 13048, Kuwait
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12
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DONG B, GALINDO C, SHIN E, ACOSTA C, PAGE A, WANG M, KIM D, OCHIAI R, PARK J, ALI M, SEIDLEIN L, XU Z, YANG J, CLEMENS J. Optimizing typhoid fever case definitions by combining serological tests in a large population study in Hechi City, China. Epidemiol Infect 2007; 135:1014-20. [PMID: 17217551 PMCID: PMC2870657 DOI: 10.1017/s0950268806007801] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Blood culture-based diagnosis can only detect a fraction of the total burden of Salmonella enterica subsp. enterica serovar Typhi. The objective of the study was to detect additional typhoid fever cases through serological tests. A total of 1732 prolonged fever episodes were evaluated using three serological tests, Widal, Tubex and Typhidot-M in a typhoid fever endemic area of southern China. A case definition which included a positive Widal test (TO>or=80 & TH>A), a positive Tubex test (>or=4) and a positive Typhidot-M test, increased the detection of cases by more than twofold from 13 to 28 cases. The case definition has a specificity of 100% and a sensitivity of 39%. Case definitions based on combinations of serological tests can detect additional typhoid fever cases with higher specificity than a single serological test. Improved case detection is essential to understand the true disease burden and can help to boost the power of intervention trials.
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Affiliation(s)
- B. DONG
- Guangxi Center for Disease Prevention and Control, Nanning, Guangxi, China
| | | | - E. SHIN
- International Vaccine Institute, Seoul, Korea
- School of Public Health and Institute of Health and Environment, Seoul National University, Seoul, Korea
- Author for correspondence: Ms E. Shin, International Vaccine Institute, Research Park, San 4-8 Bongcheon-7 dong, Kwanak-gu, Seoul, Korea 151-818. ()
| | | | - A. L. PAGE
- International Vaccine Institute, Seoul, Korea
| | - M. WANG
- Guangxi Center for Disease Prevention and Control, Nanning, Guangxi, China
| | - D. KIM
- International Vaccine Institute, Seoul, Korea
| | | | - J. PARK
- International Vaccine Institute, Seoul, Korea
| | - M. ALI
- International Vaccine Institute, Seoul, Korea
| | | | - Z. XU
- International Vaccine Institute, Seoul, Korea
| | - J. YANG
- Guangxi Center for Disease Prevention and Control, Nanning, Guangxi, China
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13
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Dutta S, Sur D, Manna B, Sen B, Deb AK, Deen JL, Wain J, Von Seidlein L, Ochiai L, Clemens JD, Kumar Bhattacharya S. Evaluation of new-generation serologic tests for the diagnosis of typhoid fever: data from a community-based surveillance in Calcutta, India. Diagn Microbiol Infect Dis 2006; 56:359-65. [PMID: 16938421 DOI: 10.1016/j.diagmicrobio.2006.06.024] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2006] [Revised: 06/28/2006] [Accepted: 06/29/2006] [Indexed: 11/30/2022]
Abstract
Although typhoid fever is confirmed by culture of Salmonella enterica serotype Typhi, rapid and simple diagnostic serologic tests would be useful in developing countries. We examined the performance of Widal test in a community field site and compared it with Typhidot and Tubex tests for diagnosis of typhoid fever. Blood samples were collected from 6697 patients with fever for > or =3 days for microscopy, culture, and serologic testing and from randomly selected 172 consenting healthy individuals to assess the baseline Widal anti-Typhi O lipopolysaccharide antibody (anti-TO) and anti-Typhi H flagellar antibody (anti-TH) titers. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the 3 serologic tests were calculated using culture-confirmed typhoid fever cases as "true positives" and paratyphoid fever and malaria cases as "true negatives". Comparing cutoff values for the Widal test, an anti-TO titer of 1/80 was optimal with 58% sensitivity, 85% specificity, 69% PPV, and 77% NPV. Sensitivity was increased to 67% when the Widal test was done on the 5th day of illness and thereafter. The sensitivity, specificity, PPV, and NPV of Typhidot and Tubex were not better than Widal test. There is a need for more efficient rapid diagnostic test for typhoid fever especially during the acute stage of the disease. Until then, culture remains the method of choice.
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Affiliation(s)
- Shanta Dutta
- National Institute of Cholera and Enteric Diseases, P-33 CIT Road, Scheme XM, Beliaghata, P.O. Box 177, Calcutta 700010, India
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14
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Prakash P, Mishra OP, Singh AK, Gulati AK, Nath G. Evaluation of nested PCR in diagnosis of typhoid fever. J Clin Microbiol 2005; 43:431-2. [PMID: 15635006 PMCID: PMC540097 DOI: 10.1128/jcm.43.1.431-432.2005] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this study, nested PCR using H1-d primers, which is specific for Salmonella enterica serovar Typhi, was compared to blood culture and the single-tube Widal test. Results indicate that nested PCR can be used as a gold standard to determine the cutoff titer of the Widal test for diagnosis of typhoid fever.
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Affiliation(s)
- Pradyot Prakash
- Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India.
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15
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Willke A, Ergonul O, Bayar B. Widal test in diagnosis of typhoid fever in Turkey. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 2002; 9:938-41. [PMID: 12093703 PMCID: PMC120044 DOI: 10.1128/cdli.9.4.938-941.2002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We studied the value of the Widal tube agglutination test for the diagnosis of typhoid fever. The subjects were all adults >18 years of age and were divided into four groups: (i) 317 healthy blood donor controls, (ii) 31 bacteriologically confirmed patients with Salmonella enterica serotype Typhi, (iii) 21 patients with a clinical diagnosis of typhoid fever, and (iv) 41 febrile nontyphoid patients. Blood donor controls were screened with a slide agglutination test for the Salmonella enterica serotype Typhi O and H antigens, and positives were then tested with the Widal test. Acute- and convalescent-phase sera from patients in groups 2, 3, and 4 were obtained 7 to 10 days apart and tested by the Widal test. Using a cutoff of >or = 1/200 for the O antigen test performed on acute-phase serum gave a sensitivity of 52% and a specificity of 88% with a positive predictive value (PPV) of 76% and a negative predictive value (NPV) of 71%. This increased to 90% sensitivity and specificity with a PPV of 88% and an NPV of 93% when the convalescent-phase serum was tested. We concluded that O and H agglutinin titers of > or = 1/200 are of diagnostic significance. The Widal test is easy, inexpensive, and relatively noninvasive. It can be of diagnostic value when blood cultures are not available or practical. The results must be interpreted cautiously because of the low sensitivity of the test. The Widal test done on convalescent-phase serum gave more-reliable results with higher specificity and sensitivity.
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Affiliation(s)
- Ayse Willke
- Kocaeli Universitesi Tip Fakultesi Klinik Bakteriyoloji ve Infeksiyon Hastaliklari AD, Izmit, Turkey.
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16
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House D, Wain J, Ho VA, Diep TS, Chinh NT, Bay PV, Vinh H, Duc M, Parry CM, Dougan G, White NJ, Hien TT, Farrar JJ. Serology of typhoid fever in an area of endemicity and its relevance to diagnosis. J Clin Microbiol 2001; 39:1002-7. [PMID: 11230418 PMCID: PMC87864 DOI: 10.1128/jcm.39.3.1002-1007.2001] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Currently, the laboratory diagnosis of typhoid fever is dependent upon either the isolation of Salmonella enterica subsp. enterica serotype Typhi from a clinical sample or the detection of raised titers of agglutinating serum antibodies against the lipopolysaccharide (LPS) (O) or flagellum (H) antigens of serotype Typhi (the Widal test). In this study, the serum antibody responses to the LPS and flagellum antigens of serotype Typhi were investigated with individuals from a region of Vietnam in which typhoid is endemic, and their usefulness for the diagnosis of typhoid fever was evaluated. The antibody responses to both antigens were highly variable among individuals infected with serotype Typhi, and elevated antibody titers were also detected in a high proportion of serum samples from healthy subjects from the community. In-house enzyme-linked immunosorbent assays (ELISAs) for the detection of specific classes of anti-LPS and antiflagellum antibodies were compared with other serologically based tests for the diagnosis of typhoid fever (Widal TO and TH, anti-serotype Typhi immunoglobulin M [IgM] dipstick, and IDeaL TUBEX). At a specificity of > or =0.93, the sensitivities of the different tests were 0.75, 0.55, and 0.52 for the anti-LPS IgM, IgG, and IgA ELISAs, respectively; 0.28 for the antiflagellum IgG ELISA; 0.47 and 0.32 for the Widal TO and TH tests, respectively; and 0.77 for the anti-serotype Typhi IgM dipstick assay. The specificity of the IDeaL TUBEX was below 0.90 (sensitivity, 0.87; specificity, 0.76). The serological assays based on the detection of IgM antibodies against either serotype Typhi LPS (ELISA) or whole bacteria (dipstick) had a significantly higher sensitivity than the Widal TO test when used with a single acute-phase serum sample (P < or = 0.007). These tests could be of use for the diagnosis of typhoid fever in patients who have clinical typhoid fever but are culture negative or in regions where bacterial culturing facilities are not available.
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Affiliation(s)
- D House
- Department of Biochemistry, Imperial College of Science, Technology and Medicine, Exhibition Road, South Kensington, London SW7 2AZ, United Kingdom.
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17
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Doherty CP, Saha SK, Cutting WA. Typhoid fever, ciprofloxacin and growth in young children. ANNALS OF TROPICAL PAEDIATRICS 2000; 20:297-303. [PMID: 11219168 DOI: 10.1080/02724936.2000.11748151] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Typhoid fever remains a significant public health problem in Southern Asia, particularly with the emergence of multi-resistant strains of Salmonella typhi in the late 1980s. Use of ciprofloxacin in children, although discouraged, is increasing and we aimed to assess whether its use affects growth or the prevalence of joint symptomology. Children under 6 years of age diagnosed as typhoid fever on the basis of a positive Widal test were recruited in the outpatient department of a paediatric teaching hospital after treatment had been initiated. During 6 months follow-up, prevalences of arthritis/arthralgia and ponderal, linear and knemometric growth were recorded. Seventy-five children were recruited (mean age 32 months, mean weight-for-height Z-score--1.3, mean height-for-age Z-score 1.4) and 29 (39%) of them received ciprofloxacin. No significant adverse effects on ponderal, linear or knemometric growth, or on the incidence of arthritis/arthralgia were found to be associated with the use of ciprofloxacin. Knemometric and ponderal catch-up growth was demonstrable 30 days after diagnosis but linear growth was still declining 3 months after diagnosis with catch-up growth demonstrable only after 6 months. We conclude that ciprofloxacin is commonly used in typhoid fever and has no adverse effects on growth or joint symptomology.
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Affiliation(s)
- C P Doherty
- Department of Child Health, University of Glasgow, Royal Hospital for Sick Children, Yorkhill, Glasgow G3 8SJ, UK.
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18
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Parry CM, Hoa NT, Diep TS, Wain J, Chinh NT, Vinh H, Hien TT, White NJ, Farrar JJ. Value of a single-tube widal test in diagnosis of typhoid fever in Vietnam. J Clin Microbiol 1999; 37:2882-6. [PMID: 10449469 PMCID: PMC85403 DOI: 10.1128/jcm.37.9.2882-2886.1999] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/1999] [Accepted: 06/03/1999] [Indexed: 11/20/2022] Open
Abstract
The diagnostic value of an acute-phase single-tube Widal test for suspected typhoid fever was evaluated with 2,000 Vietnamese patients admitted to an infectious disease referral hospital between 1993 and 1998. Test patients had suspected typhoid fever and a blood culture positive for Salmonella typhi (n= 1,400) or Salmonella paratyphi A (n = 45). Control patients had a febrile illness for which another cause was confirmed (malaria [n = 103], dengue [n = 76], or bacteremia due to another microorganism [n = 156] or tetanus (n = 265). An O-agglutinin titer of >/=100 was found in 18% of the febrile controls and 7% of the tetanus patients. Corresponding values for H agglutinins were 8 and 1%, respectively. The O-agglutinin titer was >/=100 in 83% of the blood culture-positive typhoid fever cases, and the H-agglutinin titer was >/=100 in 67%. The disease prevalence in investigated patients in this hospital was 30.8% (95% confidence interval, 26.8 to 35.1%); at this prevalence, an elevated level of H agglutinins gave better positive predictive values for typhoid fever than did O agglutinins. With a cutoff titer of >/=200 for O agglutinin or >/=100 for H agglutinin, the Widal test would diagnose correctly 74% of the blood culture-positive cases of typhoid fever. However, 14% of the positive results would be false-positive, and 10% of the negative results would be false-negative. The Widal test can be helpful in the laboratory diagnosis of typhoid fever in Vietnam if interpreted with care.
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Affiliation(s)
- C M Parry
- Wellcome Trust Clinical Research Unit, Cho Quan Hospital, Ho Chi Minh City, Vietnam.
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Affiliation(s)
- S K Saha
- Department of Microbiology, Bangladesh Institute of Child Health, Dhaka Shishu (Children) Hospital, Popular Diagnostic Centre.
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