Enteric fever, also referred to as typhoid fever, is a dangerous infectious disease brought on by the Salmonella enterica serotype typhi (S. typhi) bacteria. Contaminated food and water are the main ways that this sickness spreads, making it a serious public health issue.[1]

Salmonella typhi is the primary cause of typhoid fever and is a human-only bacterium. Human carriers are the main source of transmission for S. typhi because it does not have animal reservoirs, unlike a number of other diseases that may exist in both people and animals. [2]

Consuming tainted food or water allows the bacteria to enter the body. S. typhi travels to the intestines after ingestion, where it can pass through the intestinal barrier and enter the circulation. It then spreads to many organs, including the gallbladder, spleen, and liver.[3]

Typhoid fever symptoms often show up one to three weeks after bacterial exposure. Early symptoms include chills, headaches, fatigue, stiffness in the muscles, and digestive problems such as constipation, diarrhoea, or stomach discomfort. The temperature gradually rises to 104°F (40°C).[1]

Given the prevalence of typhoid fever in endemic areas and the demand for precise, quick diagnostic techniques, a comparison of the use of the Widal test and Typhi dot immunoassay for typhoid fever diagnosis is important.[4]

The purpose of this study is to compare and contrast the Widal test's and the Typhi dot immunoassay's efficacy in evaluating the two serological tests. This study aims to provide a comprehensive analysis of both tests in order to evaluate how well they detect typhoid illness.   [1]

Patients with acute febrile illness of any age or sex that were indicative of typhoid fever were the subjects of this observational study, which was conducted by the serological section of the Department of Microbiology at the Teerthanker Mahaveer Hospital and Research Center. The study included 139 samples in total, and its conduct was approved by the Institutional Ethical Committee (IEC). Detailed patient information was obtained from the medical record department as well as the patients themselves during the study period.

Blood sample was collected from each patient in plane vials, and the entire sample was transported to the Serological section of the Microbiology department. The widal test involves centrifuging a blood sample in accordance with the manufacturer's instructions, and the separated sera was then subjected to a widal slide agglutination by TYDAL.

The foundation of the Widal test is the agglutination principle, which occurs when specific antibodies in an individual's serum react with bacterial antigens that match.[5]

The fast assay based on immunochromatography was used to perform the Typhi Dot test. The Typhi Dot test uses a dot blot format and is based on ELISA (enzyme-linked immunosorbent concept [6]. The test strip was coated with diluted patient serum. IgM and IgG antibodies for S. typhi was bind through the fixed antigens on the strip if they are present in the serum. After that, an enzyme substrate is added, which results in a color shift that indicates a successful outcome.

Statistical analysis

When appropriate data was submitted to chi square test. Data interpretation was done through the use of SPSS software while through excel 7.0 software, graph production was made easy

Ethical approval

This investigation, with reference number TMU/IEC/2024-PG/131, was approved by the institutional ethical committee at Teerthanker Mahaveer University. Each participant gave their informed consent prior to sample collection and processing. The goal and nature of the study were explained in general to the participants, who were also informed that they might withdraw or refuse participation at any time without affecting their ability to get additional medical care. The collected data was kept confidential.

The research was conducted at Teerthanker Mahaveer Hospital in Moradabad, Uttar Pradesh, in the serological section of the microbiology department, following Institutional Ethical Committee (IEC) approval. The Widal test was used alongside with the typhoid test to examine 139 samples for typhoid fever pathogens.

Table: 1 the gender distribution of the study population by age groups

1. The gender distribution of the study population by age groups

According to the first table, out of the 139 samples collected from different age groups, 51 were male and 88 were female. 40 patients (28.77%) were between the ages of 0-10, 34 patients (24.46%) were between the ages of 21-30, and the fewest patients were between the ages of 71-80.

Table 2.  Prevalence of case results in WIDAL and TYPHIDOT TESTS

1. Prevalence of Typhoid Fever cases in Widal and Typhoid Test

Out of 139 cases, 45 (32.37%) tested positive for the Widal test and 51 (36.69%) tested positive for the Typhidot test, according to the incidence of typhoid fever cases based on the two diagnostic tests.

Table 3: Comparison between widal and typhoid test results

III Agreement Between WIDAL and TYPHIDOT TEST

Among 51 patients with positive Typhidot results, 44 were positive and 7 were negative on the Widal test. In the meantime, among the 45 patients who tested positive on the Widal test, 44 also tested positive, and 1 patient was negative on the Typhidot test

Table 4: Distribution of samples for agglutination in the Widal test

IV Distribution of samples for agglutination in the Widal test

 As a screening procedure, a qualitative slide agglutination test was done on each patient sample. The findings of the Widal test, which used Widal test kits for both anti-H and anti-O antigens, are shown in the table.

For more than a century, the Widal test has been the main technique used to diagnose typhoid disease. The test kit is still widely used throughout developing nations where typhoid fever is widespread, despite long-standing doubts over its diagnostic accuracy. For the qualitative detection and differentiation of IgM and IgG anti-Salmonella typhi and paratyphi in human serum or plasma, the Typhi dot test is an innovative, dependable cost-effective, and rapid serological assay.

A comparison of the Widal and Typhi dot tests for the diagnosis of enteric fever provides significant details about their effectiveness, cross-reactivity, and the variables influencing their results., conducted in the microbiology department at Teerthanker Mahaveer Hospital, Moradabad, U.P. after the approval of IEC. Table 1displays the demographics of the study participants. The age group 0-10 indicates a representation of 40 (28.77%) aligning with the epidemiology of enteric fever in areas where it is common. The reason contributing to typhoid fever in children more common than in adults can be weekened immune system, poor hygiene practices, contaminated food and water, lack of awareness. This discovery corresponds with a study by Antillon et al (2017), which indicated that young adults carry a substantial load of typhoid fever in low- and middle-income nations.[7] Raksha Singh et al (2021) recorded the age group 41–70 years at maximum age distribution. [8]

Table 2 compares the performance of Widal and Typhidot tests in positive typhoid cases. In the study involving 139 respondents, the Typhidot test showed a slightly greater positivity rate of 36.69% compared to the Widal test, which had a rate of 32.37%. The p – value is 0.4487. Not significant at p<0.0. Similarly, D Kumar Jyoti et al. (2017) found that out of 120 clinical isolates, 30% were typhoid-positive, compared to 22.5% in the Widal test.[9] Meanwhile, Khoharo et al. (2011) reported that the Typhidot test was positive in 74 (97.36%) cases, compared with the Widal test which was positive in 56 (73.68%) cases.[10]

Table 3 presents the correlation between Widal and Typhidot tests. Among the 51 Typhidot-positive patients, 44 were positive and 7 were negative for the Widal test. Meanwhile, among the 45 patients who tested positive on the Widal test, 44 were found positive, and 1 patient was negative on the Typhidot test.

Table 4 displays the titer of both anti-H and anti-O antigens in the qualitative slide agglutination test for 45 individuals who tested positive for typhoid fever based on the Widal test, employing an antibody titer of 1:160 for both "O" and "H" antigens as threshold values to signify a recent typhoid infection, leading to a prevalence of 32.37%, with a notable count of 25 (17.98%) positive slide agglutination results reflecting tube titer outcomes of O/320, H/160. Similar findings were reported by Araya G. et al.

According to the current research, decisions regarding treatment shouldn't be made only based on slide agglutination results, even though the Widal test is a useful screening tool. This evaluation emphasizes the ongoing need for improved diagnostic techniques in the efficient treatment of typhoid fever, particularly in endemic regions where timely treatment is essential for patient recovery. Frequent use of Typhidot in clinical settings may improve diagnostic outcomes. The advantages of the Typhidot immunoassay over the traditional Widal test for typhoid fever diagnosis are shown by the comparative analysis. To further increase precision, future research should focus on enhancing these diagnostic tools and looking into combination testing strategies.

 Limitations

There are some limitations in our study as we perform only Widal slide Agglutination test instead of tube test and the sample size was also limited however if we increase the sample size our result can be better.

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