Widal Tube Agglutination Test Research Articles

Health facility-based prevalence of typhoid fever, typhus and malaria among individuals suspected of acute febrile illnesses in Southwest Region, Ethiopia.

Acute febrile illnesses such as typhoid fever, typhus, and malaria are still major causes of hospital admission in many parts of Ethiopia. However, there are substantial gaps in the monitoring systems, which result in a lack of knowledge about the geographic distribution and role of common pathogens, particularly in rural areas. Thus, this study was aimed at assessing the seroprevalence of typhoid fever, typhus, and malaria among suspected acute febrile patients at the MTU Teaching Hospital and Mizan-Aman Health Center, Southwest region of Ethiopia. A health facility-based cross-sectional study was carried out from July to October 2022. Blood samples were collected from a total of 384 individuals. Widal and Weilfelix direct card agglutination and tube agglutination test methods were used for the Salmonella enterica serotype Typhi (S. typhi) and Rickettsia infections. The diagnosis of malaria was made using thick and thin blood smears. Questionnaires given by interviewers were used to gather information on risk factors and other sociodemographic factors. The data was analyzed using STATA/SE 14.0. A total of 371 patients were tested for S. Typhi and Rickettsia infections using direct card agglutination and tube agglutination methods. Using the screening test, 20.5% (76/371) patients were reactive either for O or H antigens or both, of which 55.3% (42/76) were reactive by the titration test at the cutoff value ≥ 1:80. About 17.5% (65/371) were reactive to OX19 antigen by card agglutination test, and of which 58.5% (38/65) were reactive by the titration test at the cutoff value ≥ 1:80. The overall seroprevalence of S. Typhi and Rickettsia infections using combined direct card and tube agglutination techniques was 11.3% (42/371) and 10.2% (38/371), respectively. Out of 384 suspected malaria patients, 43 (11.2%) were found positive either for P. falciparum, 27 (7.03%), or P. vivax, 16 (4.2%). In this study, typhoid fever, typhus, and malaria were found among symptomatic acute febrile patients. To increase disease awareness, it is necessary to provide sustainable health education about risk factor behaviors, disease transmission, and prevention strategies. In addition, improving laboratory diagnosis services and early treatment may also lower the likelihood of potentially fatal consequences.

Comparison of rapid serological diagnostic test in diagnosing typhoid fever in a tertiary care centre in western Uttar Pradesh

: In the study we compare the sensitivity and specificity of two commonly used rapid serological test, Widal test and Typhidot, in the diagnosing of Typhoid fever. Serum samples coming to the microbiology laboratory for routine testing over the period from September 2019 to November 2020 were analysed for the comparison for the presence of the Salmonella antibodies by carrying out the Typhidot and Widal tube agglutination test in tertiary care centre.: Out of 580 blood specimen, 49.3% cases were positive by Typhidot and 38.6% cases were positive by Widal method.Typhidot is a rapid and more sensitive test for early diagnosis of typhoid fever. It is now commercially available for the diagnosis of typhoid fever in areas with limited resources. Widal test showed the sensitivity and specificity of 37% & 62.4% respectively. Typhi dot test showed sensitivity of 41.4% and specificity of 56.5%.

COMPARISON OF QUANTITATIVE TUBE AGGLUTINATION AND SEMIQUANTITATIVE SLIDE AGGLUTINATION TEST FOR DIAGNOSING OF THE SUSPECTED CASES OF ENTERIC FEVER

Introduction: Enteric fever is the major health problem of developing country like India, with a notable morbidity and mortality. Isolation of Salmonella the causative agent from Blood is the standard laboratory method for diagnosis, but it is not available at PHC level. So, rapid and affordable diagnostic test like Widal tube and slide agglutination test are used. The present study was done to comparatively evaluate the Widal slide agglutination and tube agglutination test in detecting enteric fever.
 Methods: A total of 500 patients with clinical presentation suggestive of enteric fever were included in the study whose venous blood was collected. All the samples were tested for the presence of anti O and anti H agglutinins against S. typhi and S. paratyphi A by semi quantitative slide and quantitative tube agglutination tests as per standard protocols. The titers of 1:80 (O agglutinins) and 1:160 (H agglutinins) were taken as the significant titer for the diagnosis of enteric fever.
 Results: Out of 500 collected samples, 183 (36.6%) was positive by slide agglutination test, whereas, only 145 (29%) were positive by tube agglutination method. The slide test had a sensitivity of 97.2%, specificity of 88.1%, positive predictive value of 77% and negative predictive value of 98.7% as compared to Widal tube agglutination test.
 Conclusions: Due to high false positivity shown by slide test, it is suggested that serological diagnosis should not be made solely on the basis of slide test rather its results should be confirmed by using Widal tube agglutination test.
 Keywords: Enteric fever, Slide agglutination test, Widal tube agglutination test, Sensitivity, Specificity

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Comparison of Antibody Titre Against Salmonella Species among Healthy Individuals and Febrile Patients

Background: Widal tube agglutination test is a widely used laboratory test for diagnosis of enteric fever especially in resource limited countries where blood culture are not routinely available. We studied the titres from different groups including febrile and healthy populations in order to identify the significant agglutination titre. Materials and Methods: This was a hospital based cross-sectional study. Subjects were divided into three groups: 1) 60 healthy blood samples from volunteer students, 2) 60 febrile non-typhoidal cases and 3) 58 culture positive patient for enteric fever. Results: Among 60 apparently healthy volunteers, agglutination of ≥ 1:20 for anti O and anti-H titres against serotype Typhi were seen in 40 and 46 samples respectively. A significant proportion of sample had a titre of ≥1:80 (n=19) and 1:160 (n=14) for anti O and anti-H titres against serotype Typhi respectively among healthy individuals. Similar observations were seen in febrile non typhoidal cases except for one which had a titre of ≥1:320 for anti O and anti-H titres against serotype Typhi. In blood culture positive typhoid cases, 56 samples showed agglutinations of ≥1:80 for both anti O and anti-H titres against serotype Typhi. However two of the total sample tested showed no agglutinations. In all cases from three groups, anti-H titre for S. enterica serotype Paratyphi A and B were below 1:80. Conclusions: Widal test can be used as presumptive diagnostic tool in all the suspected cases of enteric fever if the titres are specifically raised.Keywords: enteric fever; titre; widal aggultination test.

Prevalence and Antibiogram Pattern of Salmonella enterica Serotypes inGarhwal Region: First Report from Foothills of Himalayas

Introduction: Enteric fever, caused by Salmonella enterica subsp. Enterica serotype Typhi and Paratyphi, is endemic in India with an incidence of 102–2219/100,000 populations. The definitive diagnosis of enteric fever in patients with compatible clinical picture is isolation of Salmonellae from blood, bone marrow, stool or urine, and demonstration of four‑fold rise in antibody titer to both O and H antigen of the organism between acute and convalescent‑phase sera. Aim: The aim of the study was to study the prevalence of various serotypes of S. enterica and their antibiogram in foot hills of Himalayas. Materials and Methods: During February 2012–January 2013, all clinically suspected patients were screened for enteric fever by Widal tube agglutination test. For the isolation of etiology, venous blood, stool and urine specimen were obtained from patients with antibody titer of ≥80 and 160 for anti‑O agglutinin and anti‑H agglutinin of Salmonella typhi, respectively, and ≥20 for anti-H agglutinin of S. paratyphi A and S. paratyphi B. Characterization and antibiogram determination of the isolates was done by conventional microbiological methods including Kirby–Bauer’s disc diffusion technique. Result: Among 1173 suspected cases, 373 showed a high titer of antibodies against O (≥80), H (≥160), AH (≥20), and BH (≥20) antigens. A total of 81 isolates were obtained from 76 patients (29 from blood and 49 from stool and three from urine), of which 54 were identified as Salmonella typhi, 20 as Paratyphi A and seven as Paratyphi B. Extended‑spectrum beta‑lactamase production was observed in four isolates of S. typhi. Ciprofloxacin followed by co‑trimoxazole was resistant to 46.5 and 36.5% of the isolates, respectively. Conclusion: This report indicates a significant percentage of drug resistance in S. enterica serotypes in Garhwal region. Periodic monitoring of the antibiogram pattern along with the implementation of strict antibiotic policies and patient education is needed. Keywords: Blood culture, extended‑spectrum beta‑lactamase, Salmonella typhi, typhoid fever, Widal test.

Prevalence and antibiogram pattern of Salmonella enterica serotypes in Garhwal Region: First report from foothills of himalayas

Introduction: Enteric fever, caused by Salmonella enterica subsp. Enterica serotype Typhi and Paratyphi, is endemic in India with an incidence of 102–2219/100,000 populations. The definitive diagnosis of enteric fever in patients with compatible clinical picture is isolation of Salmonellae from blood, bone marrow, stool or urine, and demonstration of four‑fold rise in antibody titer to both O and H antigen of the organism between acute and convalescent‑phase sera. Aim: The aim of the study was to study the prevalence of various serotypes of S. enterica and their antibiogram in foot hills of Himalayas. Materials and Methods: During February 2012–January 2013, all clinically suspected patients were screened for enteric fever by Widal tube agglutination test. For the isolation of etiology, venous blood, stool and urine specimen were obtained from patients with antibody titer of ≥80 and 160 for anti‑O agglutinin and anti‑H agglutinin of Salmonella typhi, respectively, and ≥20 for anti-H agglutinin of S. paratyphi A and S. paratyphi B. Characterization and antibiogram determination of the isolates was done by conventional microbiological methods including Kirby–Bauer’s disc diffusion technique. Result: Among 1173 suspected cases, 373 showed a high titer of antibodies against O (≥80), H (≥160), AH (≥20), and BH (≥20) antigens. A total of 81 isolates were obtained from 76 patients (29 from blood and 49 from stool and three from urine), of which 54 were identified as Salmonella typhi, 20 as Paratyphi A and seven as Paratyphi B. Extended‑spectrum beta‑lactamase production was observed in four isolates of S. typhi. Ciprofloxacin followed by co‑trimoxazole was resistant to 46.5 and 36.5% of the isolates, respectively. Conclusion: This report indicates a significant percentage of drug resistance in S. enterica serotypes in Garhwal region. Periodic monitoring of the antibiogram pattern along with the implementation of strict antibiotic policies and patient education is needed. Keywords: Blood culture, extended‑spectrum beta‑lactamase, Salmonella typhi, typhoid fever, Widal test.

Serological profile of acute undifferentiated fever cases attending a tertiary care hospital: emergence of scrub typhus in Telangana State

Introduction: Present study was undertaken to elucidate aetiology of acute undifferentiated fevers and prevalence of scrub typhus among patients admitted in our hospital. Materials & Methods: 100 consecutive serum samples received during the period May 2016 to October 2016 were tested for dengue NS1 antigen by ELISA, chikungunya Ig M antibodies by MAC- ELISA, widal tube agglutination test, leptospira Ig M antibodies by ELISA, plasmodium falciparum, plasmodium vivax, by Parahit F and V,Weil Felix tube agglutination test, orientiatsusugamushi IgM and IgG antibodies by Immunochromatography. Results: Out of hundred samples subjected to more extensive analysis, 39 samples were positive for Dengue which included 28 samples positive for IgM antibodies, 6 samples were positive for IgM antibodies and NS1 antigen, 5 positive for NS1 antigen. 19 were found to be positive for antibodies to orientiatsusugamushi by Immunochromatography. Conclusion: Though the dengue fever is often considered and investigated by the physicians in all such cases, other infections are often ignored or do not figure in the differential diagnosis particularly during outbreaks. There is a need to investigate for scrub typhus, an acute febrile illness caused by Orientia tsusugamushi (Ricketssia tsusugamushi) which is a re-emerging disease in India.

Baseline Antibody Titre against Salmonella enterica in Healthy Population of Mumbai, Maharashtra, India.

Objective The aim of this study was to establish a baseline titre for the population of Mumbai, Maharashtra, India. Method Four hundred healthy blood donors, attending blood donation camps, were screened using a survey questionnaire. Widal tube agglutination test was performed on the diluted sera (with 0.9% normal saline) of blood donors, with final dilution ranging from 1 : 40 to 1 : 320. Results Out of 400 individuals providing samples, 78 (19.5%) individuals showed antibody titres ≥ 1 : 40 for at least one antigen and 322 (80.5%) showed no agglutination. The baseline antibody titres against O antigen and H antigen of Salmonella enterica serotype Typhi were found to be 1 : 40 and 1 : 80, respectively. Similarly, the baseline antibody titres for the H antigen of Salmonella enterica serotypes Paratyphi A and Paratyphi B were found to be 1 : 40 and 1 : 80, respectively. Conclusion Thus, it was noted that the diagnostically significant cutoff of antibody titre from acute phase sample was ≥ 1 : 80 for S. Typhi O antigen and titre of ≥ 1 : 160 for both S. Typhi H antigen and S. Paratyphi BH antigen. Antibody titre of ≥ 1 : 80 can be considered significant for S. Paratyphi AH antigen.

Baseline widal titre among the healthy individuals: a study in and around Badnapur, Marathwada region at Tertiary Care Hospital

Objectives: Present study was carried out to determine average baseline widal titer among the healthy individuals in and around Badnapur, Marathwada Region. Methods: A total of 340 blood samples were collected from the apparently healthy individuals were further subjected to standard quantitative widal tube agglutination test to find out baseline widal titre among healthy individuals. Result: The most frequently recorded titre for O agglutinins were 1:40 and For the H agglutinins were 1:80. The baseline anti-H agglutinin titre of the paratyphoid A(H) were 1:40 and Paratyphoid B(H) were 1:20. Conclusion: Evaluation of baseline widal titre from single serum sample is mandatory for proper interpretation widal test to guide the clinicians. Therefore it was concluded that the cut-off values for TO, TH, A(H), B(H), were 1:40, 1:80, 1:40, and 1:20 respectively for the diagnosis purpose of enteric fever in this region. Keywords: Enteric fever, Salmonella Typhi, Endemic titre

Diagnostic efficacy of Widal slide agglutination test against Widal tube agglutination test in enteric fever

Introduction: Enteric fever is an endemic disease in India and warrants rapid and affordable diagnosis. The Widal slide agglutination test is a commonly used rapid screening test for this purpose. The literature available on its diagnostic ability in comparison to the tube agglutination test is however scanty. Hence, this study aims to evaluate the efficacy of the Widal slide agglutination test and the tube agglutination test for the diagnosis of enteric fever. Materials and Methods: A total of 1470 sera were collected during the study period of one year from patients having pyrexia of unknown origin. All the samples were tested for the presence of anti O and anti H agglutinins against S. typhi and S. paratyphi A by semi quantitative slide and quantitative tube agglutination tests as per standard protocols. The titers of 1:80 (O agglutinins) and 1:160 (H agglutinins) were taken as the significant titer for the diagnosis of enteric fever. The results of the slide agglutination test were compared with the tube agglutination test and analyzed using Fisher's exact test. The sensitivity, specificity, positive and negative predictive values of slide agglutination were calculated using the tube agglutination method as a standard for comparison. Results: Of the 294 slide positive samples, 209 (71.1%) samples tested negative by the tube agglutination test. The sensitivity, specificity, positive and negative predictive values for the slide agglutination test were observed to be 100 % (CI 95.75-100%), 84.91% (CI 82.93-86.73%), 28.91% (CI 23.84-34.45%) and 100% (CI 99.69-100%) respectively. Conclusion: Serological diagnosis of enteric fever should always be confirmed by the tube agglutination test rather than depending solely upon the rapid slide agglutination test results.

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AIM AND OBJECTIVE: The interpretation of the Widal test depends upon the baseline titre among healthy individuals in a particular geographical area. This study was undertaken to determine the baseline Widal titre in apparently healthy individuals in, Hadoti region, Rajasthan. MATERIALS AND METHODS: Blood samples were collected from healthy blood donors (n= 200) who attended blood bank of this institution from May 2012 to August 2012. The Widal tube agglutination test was carried out. 0.5 ml of two fold serially diluted patients' sera (dilutions from 1:20 to 1:160) in 0.9% normal saline was tested by adding an equal amount of antigen. RESULTS: Of the 200 serum samples which were tested, 108 serum samples were positive for agglutinins against Salmonella serotypes (≥ 1:20) and 92 serum samples were negative for agglutinins. Among 54 samples with an anti-O titer (≥ 1:20) , 39 samples had titres of 1:40. Among the 63 samples demonstrating anti-H titres of ≥ 1:20 to salmonella serotype, 48 had a titer of 1:40. For salmonella Paratyphi A and B, anti-H titres of 1:20 were found in 3% and 1.5%, respectively, of all samples tested. CONCLUSION: We recommended that the significant titre of the 'H' agglutinin and the 'O' agglutinin of Salmonella Typhi is ≥ 1: 80. While the significant titre of the 'H' agglutinins of Salmonella Paratyphi A and Salmonella Paratyphi B is ≥ 1: 40.

Determination of Baseline Widal Titres Amongst Apparently Healthy Blood Donors in Ahmednagar, Maharashtra, India

Enteric fever is endemic in all parts of India. The Widal agglutination test is widely used for its diagnosis. But the interpretation of Widal test depends upon the baseline titre which is prevalent amongst healthy individuals in a particular geographical area. Present study was undertaken to establish the normal baseline titre in apparently healthy blood donors and also to determine cutoff values for the Widal test. One hundred and three (103) sera were tested by the Widal tube agglutination test from January 2012 to February 2013. Eighty four (81.55%) sera were positive for agglutinins (titre ≥ 1:20) and the remaining 19 were negative. 31.64% sera were positive for agglutinins of 'O' antigen of Salmonella typhi (TO) at a titre of 1:40, 33.87% sera were positive for 'H' antigen of Salmonella typhi (TH) at a titre of 1:40 and 38.46% and 36.84% sera were positive for 'H' antigen of Salmonella paratyphi A (AH) and Salmonella paratyphi B (BH) respectively, both at a titre of 1:80. Therefore, the baseline titre for TO and TH was noted to be 1:40 and that for AH and BH was noted to be 1:80 and therefore, the cutoff level for TO and TH was ≥ 1:80 and that for AH and BH was ≥ 1:160.

Modifications Influencing Widal Test Reactivity in a Novel Microplate Assay

Reliability of the Widal tube agglutination test has been the subject of many controversies over the years. This study was performed to assess the effect of certain modifications on the performance of Widal test in a novel microplate assay. Sera from 37 patients (21 males; 16 females) (mean age 28 +/- 7 years) were tested in the Immunology Unit at King Khalid University Hospital, Riyadh. Among them were 26 patients with suspected typhoid fever and 11 had bacteriologically confirmed diagnosis of Salmonella infection. The modifications included either the use of 0.5% bovine serum albumin (BSA), absorption of sera with sheep red blood cells (SRBC) or heat inactivation of sera. Compared with Widal tube agglutination test, microplate assay with SRBC absorption of the sera from patients with suspected typhoid fever was not only associated with enhancement of detection titers for both H (p < or = 0.001) and O (p < or = 0.005) Salmonella agglutinins but also the percentage of reactivity. The presence of BSA augmented detection titers for Salmonella H agglutinins (p < or = 0.02) only. Heat inactivation of sera however was found to be associated with reduction in the detectable titers for both H (p < or = 0.03) and O (p < or = 0.01) agglutinins. Increased titers of Salmonella agglutinins were also evident in 11 patients with confirmed diagnosis of Salmonella infection. The novel microplate agglutination assay using the SRBC absorption was associated with enhancement in Widal test reactivity and appears to be a useful alternative for the diagnosis of Salmonella infection.

Evaluation of the Widal tube agglutination test for the diagnosis of typhoid fever among children admitted to a rural hdospital in Tanzania and a comparison with previous studies

BackgroundThe diagnosis of typhoid fever is confirmed by culture of Salmonella enterica serotype Typhi (S. typhi). However, a more rapid, simpler, and cheaper diagnostic method would be very useful especially in developing countries. The Widal test is widely used in Africa but little information exists about its reliability.MethodsWe assessed the performance of the Widal tube agglutination test among febrile hospitalized Tanzanian children. We calculated the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of various anti-TH and -TO titers using culture-confirmed typhoid fever cases as the "true positives" and all other febrile children with blood culture negative for S. typhi as the "true negatives."ResultsWe found that 16 (1%) of 1,680 children had culture-proven typhoid fever. A single anti-TH titer of 1:80 and higher was the optimal indicator of typhoid fever. This had a sensitivity of 75%, specificity of 98%, NPV of 100%, but PPV was only 26%. We compared our main findings with those from previous studies.ConclusionAmong febrile hospitalized Tanzanian children with a low prevalence of typhoid fever, a Widal titer of ≥ 1:80 performed well in terms of sensitivity, specificity, and NPV. However a test with improved PPV that is similarly easy to apply and cost-efficient is desirable.