VALIDATION OF NELWAN SCORE AS A SCREENING TOOL FOR THE DIAGNOSIS OF TYPHOID FEVER
DOI:
https://doi.org/10.71000/ez5khd92Keywords:
Antimicrobial resistance, Blood culture, Clinical diagnosis, Diagnostic accuracy, Nelwan Score, Sensitivity and specificity, Typhoid fever.Abstract
Background: Typhoid fever, caused by Salmonella typhi and Salmonella paratyphi, remains a major public health concern in endemic regions due to diagnostic challenges and limited laboratory resources. Clinical diagnosis is often confounded by nonspecific symptoms that mimic other febrile illnesses. The Nelwan Score, a simple clinical scoring system, offers a potential low-cost tool to aid diagnosis where advanced testing is unavailable.
Objective: To determine the diagnostic accuracy of the Nelwan Score for diagnosing typhoid fever, using blood culture as the gold standard.
Methods: A validation study was conducted at the Department of Medicine, Khyber Teaching Hospital, Peshawar, over six months. A total of 223 adult patients (aged 18–70 years) presenting with suspected typhoid fever were enrolled through non-probability consecutive sampling. The Nelwan Score was calculated for each participant, with a score >10 considered suggestive of typhoid fever. Blood culture using the BD BACTEC 9050 system served as the reference standard. Data were analyzed using IBM SPSS version 25 to determine sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy.
Results: Of 223 participants, 72 (32.3%) were clinically positive for typhoid by the Nelwan Score, while 58 (26.0%) were culture-positive for S. typhi. The score demonstrated a sensitivity of 86.2%, specificity of 86.7%, PPV of 69.4%, NPV of 94.7%, and an overall diagnostic accuracy of 86.5%. The strong NPV indicates its reliability as a screening tool for excluding typhoid fever in endemic, resource-limited settings.
Conclusion: The Nelwan Score showed excellent diagnostic accuracy and can serve as an effective, low-cost screening tool for typhoid fever in regions with limited diagnostic capacity, aiding timely management and rational antibiotic use.
References
Nelwan EJ, Paramita LPL, Sinto R, Subekti D, Hosea FN, Nugroho P, Pohan HT. Validation of the Nelwan Score as a screening tool for the diagnosis of typhoid fever in adults in Indonesia. PLoS One. 2023;18(5):e0256508.
Tanmoy AM, Hooda Y, Sajib MSI, Rahman H, Sarkar A, Das D, et al. Trends in antimicrobial resistance amongst Salmonella Typhi in Bangladesh: A 24-year retrospective observational study (1999-2022). PLoS Negl Trop Dis. 2024;18(10):e0012558.
Amsalu T, Genet C, Adem Siraj Y. Salmonella Typhi and Salmonella Paratyphi prevalence, antimicrobial susceptibility profile and factors associated with enteric fever infection in Bahir Dar, Ethiopia. Sci Rep. 2021;11(1):7359.
Jacob JJ, Pragasam AK, Vasudevan K, Veeraraghavan B, Kang G, John J, et al. Salmonella Typhi acquires diverse plasmids from other Enterobacteriaceae to develop cephalosporin resistance. Genomics. 2021;113(4):2171-6.
Simion T, Abate A, Alemayehu T, Ali MM. Prevalence of Salmonella Typhi, its associated factors and antimicrobial susceptibility profile among patients attending Hawassa University Comprehensive Specialized Hospital, Hawassa, Ethiopia. BMC Infect Dis. 2024;24(1):1224.
Khattak Z, Aala R, Sani N, Khan SA, Khan S, Shah SA, et al. Prevalence and antimicrobial susceptibility of Salmonella enterica Typhi in febrile patients: a cross-sectional study. J Infect Dev Ctries. 2025;19(6):904-12.
da Silva KE, Date K, Hirani N, LeBoa C, Jayaprasad N, Borhade P, et al. Population structure and antimicrobial resistance patterns of Salmonella Typhi and Paratyphi A amid a phased municipal vaccination campaign in Navi Mumbai, India. mBio. 2023;14(4):e0117923.
Kavai SM, Oyugi J, Mbae C, Kering K, Muturi P, Kebenei C, et al. Multidrug-resistant Salmonella Typhi among symptomatic and asymptomatic children in informal settlements in Nairobi, Kenya. BMC Infect Dis. 2024;24(1):1205.
Safi AUR, Bendixen E, Rahman H, Khattak B, Wu W, Ullah W, et al. Molecular identification and differential proteomics of drug resistant Salmonella Typhi. Diagn Microbiol Infect Dis. 2023;105(4):115883.
Upadhyay A, Pal D, Kumar A. Interrogating Salmonella Typhi biofilm formation and dynamics to understand antimicrobial resistance. Life Sci. 2024;339:122418.
Ahmad M, Shah N, Siddiqui MA. Frequency and Antibiotics Sensitivity Pattern of Culture-Positive Salmonella Typhi in Children. J Coll Physicians Surg Pak. 2023;33(3):303-7.
Srinivasan M, Sindhu KN, Ramanujam K, Ramasamy RK, Subramaniam S, Ganesan SK, et al. Factors Predicting Blood Culture Positivity in Children With Enteric Fever. J Infect Dis. 2021;224(Supple 5):S484-s93.
Irfan S, Zeeshan M, Rattani S, Farooqi J, Shakoor S, Hasan R, et al. Extraintestinal Seeding of Salmonella enterica Serotype Typhi, Pakistan. Emerg Infect Dis. 2021;27(3):936-8.
Manoharan A, Dey D, Putlibai S, Ramaiah S, Anbarasu A, Balasubramanian S. Epidemiology of Multidrug Resistance among Salmonella enterica serovars typhi and paratyphi A at a Tertiary Pediatric Hospital in India Over a Decade; In-silico Approach to Elucidate the Molecular Mechanism of Quinolone Resistance. Int J Infect Dis. 2022;119:146-9.
Kumar H, Manoharan A, Anbarasu A, Ramaiah S. Emergence of sulphonamide resistance in azithromycin-resistant pediatric strains of Salmonella Typhi and Paratyphi A: A genomics insight. Gene. 2023;851:146995.
Samajpati S, Pragasam AK, Mandal S, Balaji V, Dutta S. Emergence of ceftriaxone resistant Salmonella enterica serovar Typhi in Eastern India. Infect Genet Evol. 2021;96:105093.
Troman C, Horsfield ST, Abraham D, Mohan VR, Giri S, Nair S, et al. Determining genotype and antimicrobial resistance of Salmonella Typhi in environmental samples by amplicon sequencing. PLoS Negl Trop Dis. 2025;19(7):e0013211.
WHO. (2022). Enteric Fever (Typhoid or Paratyphoid) Recommendations. National Institute for Communicable Diseases.
Irfan S, Hasan Z, Qamar F, Ghanchi N, Ashraf J, Kanji A, et al. Ceftriaxone resistant Salmonella enterica serovar Paratyphi A identified in a case of enteric fever: first case report from Pakistan. BMC Infect Dis. 2023;23(1):267.
Nizamuddin S, Khan EA, Chattaway MA, Godbole G. Case of Carbapenem-Resistant Salmonella Typhi Infection, Pakistan, 2022. Emerg Infect Dis. 2023;29(11):2395-7.
Octavia S, Chew KL, Lin RTP, Teo JWP. Azithromycin-Resistant Salmonella enterica Serovar Typhi AcrB-R717Q/L, Singapore. Emerg Infect Dis. 2021;27(2):624-7.
Sahai N, John Jacob J, Kumar Arunachalam D, Kumar Das B, Kapil A, Pandey S, et al. Antimicrobial susceptibility trends of S. Typhi and S. Paratyphi in a post-COVID-19 pandemic India, from a multicenter surveillance network. Sci Rep. 2025;15(1):13777.
Fasih F, Fatima A, Baig S, Naseem S, Tauheed MM, Gohar H. Antimicrobial susceptibility of bacteraemic isolates of Salmonella enterica serovar typhi and paratyphi infection in Pakistan from 2017-2020. J Pak Med Assoc. 2023;73(3):505-10.
Qamar FN, Yousafzai MT, Dehraj IF, Shakoor S, Irfan S, Hotwani A, et al. Antimicrobial Resistance in Typhoidal Salmonella: Surveillance for Enteric Fever in Asia Project, 2016-2019. Clin Infect Dis. 2020;71(Suppl 3):S276-s84.
Dahiya S, Katiyar A, Rai S, Sharma P, Punit K, Kapil A. Ceftriaxone-resistant Salmonella Typhi isolated from paediatric patients in north India: Insights into genetic profiles and antibiotic resistance mechanisms. Indian J Med Microbiol. 2023;46:100448.
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