1. Sajadi MM, Bonabi R, Sajadi MR, Mackowiak PA. Akhawayni and the first fever curve. Clin Infect Dis 2012; 55:976–80.
2. Petersdorf RG, Beeson PB. Fever of unexplained origin: report on 100 cases. Medicine (Baltimore) 1961; 40:1–30.
3. Wright WF, Auwaerter PG. Fever and Fever of Unknown Origin: Review, Recent Advances, and Lingering Dogma. Open Forum Infect Dis. 2020;7(5): ofaa132.
4. Mackowiak PA. Concepts of fever. Arch Intern Med 1998; 158:1870–81.
5. Roth J, Blatteis CM. Mechanisms of fever production and lysis: lessons from experimental LPS fever. Compr Physiol 2014; 4:1563–604.
6. Evans SS, Repasky EA, Fisher DT. Fever and the thermal regulation of immunity: the immune system feels the heat. Nat Rev Immunol 2015; 15:335–49.
7. Durack DT. Fever of unknown origin? reexamined and redefined. Curr Clin Top Inf Dis 1991;11:35–51.
8. Iikuni Y, Okada J, Kondo H, et al. Current Fever of Unknown Origin 1982-1992, Internal Medicine, 33 (2), 1994, 67–73.
9. Chow A, Robinson JL. Fever of unknown origin in children: a systematic review. World Journal of Pediatrics 2011;7(1):5.
10. Chouchane S, Chouchane CH, Ben Meriem CH, et al. Les fie`vres prolonge´es de l’enfant. E´ tude re´trospective de 67 cas Prolonged fever in children. Retrospective study of 67 cases. Archives
de pe´ diatrie 2004;11:1319–25.
11. Fusco FM, Pisapia R, Nardiello S, et al. Fever of unknown origin (FUO): which are the factors influencing the final diagnosis? A 2005-2015 systematic review. BMC Infect Dis 2019;19(1):653.
12. Gaeta GB, Fusco FM, Nardiello S. Fever of unknown origin: a systematic review of the literature for 1995–2004. Nucl Med Commun 2006;27(3):205–11.
13. Kim YS, Kim KR, Kang JM, et al. Etiology and clinical characteristics of fever of unknown origin in children: a 15-year experience in a single center. Korean J Pediatr 2017; 60 (3):77–85.
14. Antoon JW, Peritz DC, Parsons MR, et al. Etiology and Resource Use of Fever of Unknown Origin in Hospitalized Children, Hosp Pediatr 2018; 8 (3): 135–140.
15. Cho CY, Lai CC, Lee ML, et al. Clinical analysis of fever of unknown origin in children: A 10-year experience in a northern Taiwan medical center. J Microbiol Immunol Infect 2017;50(1):40–5.
16. Wright WF, Betz JF, Auwaerter PG. Prospective Studies Comparing Structured vs Nonstructured Diagnostic Protocol Evaluations Among Patients With Fever of Unknown Origin: A Syste-
matic Review and Meta-analysis. JAMA Netw Open 2022; 5(6):e2215000.
17. Wright WF, Yenokyan G, Auwaerter PG. Geographic Influence Upon Noninfectious Diseases Accounting for Fever of Unknown Origin: A Systematic Review and Meta-Analysis. Open Forum
Infect Dis 2022;9(8):ofac396.
18. Spelman D. Fever of unknown origin in adults: Etiologies [İnternet]. In: Sexton DJ, Hall KK (eds). Uptodate [Accessed on February 2024]. https://www.uptodate.com/contents/fever-of-unk-
nown-origin-in-adults etiologies.
19. Sajadi MM, Mackowiak PA. Temperature Regulation and the Pathogenesis of Fever. Bennett JE, Dolin R, Blaser MJ. Mandell, Douglas, and Bennett’s Principles and Practices of Infectious
Diseases, 8th Edition. 8th ed. Atlanta, GA: Elsevier Health; 2015; Vol. I: 708-720.
20. Sandra G Gompf, Davis M, Contreras A. Fever of Unknown Origin (FUO). [İnternet]. In: Bronze MS (ed). Emedicine. [Accessed on May 2021]. https://emedicine.medscape.com/artic-
le/217675-overview.
21. Fever of unknown origin. Wright W, Mackowiak P. In: Bennett J, Dolin R, Blaser M, editors. Mandell, Douglas, and Bennett’s principles and practice of infectious diseases, 8th edition. Phila-
delphia: Elsevier Saunders, 2015: 721-31.
22. Wright WF, Yenokyan G, Simner PJ, et al. Geographic Variation of Infectious Disease Diagnoses Among Patients With Fever of Unknown Origin: A Systematic Review and Meta-analysis.
Open Forum Infect Dis 2022; 9:ofac151.
23. Knockaert DC, Vanneste LJ, Bobbaers HJ. Fever of unknown origin in elderly patients. J Am Geriatr Soc 1993; 41:1187.
24. Kumarasamy KK, Toleman MA, Walsh TR, et al. Emergence of a new antibiotic resistance mechanism in India, Pakistan, and the UK: a molecular, biological, and epidemiological study. Lancet
Infect Dis 2010;10:597.
25. Ryan K. Fever of Unknown Origin. Med Clin North Am. 2024;108(1):79-92.
26. Vanderschueren S, Knockaert D, Adriaenssens T, Demey W, Durnez A, Blockmans D, et al. From Prolonged Febrile Illness to Fever of Unknown Origin The Challenge Continues. Arch Int
Med. 2003. 163:1033-1041.
27. Mulders-Manders C, Simon A, Bleeker-Rovers C. Fever of unknown origin. Clinical Medicine. 2015;15:280-284.
28. Chan WP, Kosik RO, Wang CJ. Considerations and a call to action for the use of noncontact forehead infrared handheldthermometers during the COVID-19 pandemic. J Glob Health.
2021;11:021
29. Chen HY, Chen A, Chen C. Investigation of the Impact of Infrared Sensors on Core Body Temperature Monitoring by Comparing Measurement Sites. Sensors (Basel). 2020;20 (10):2885.
30. Goldman RD, Scolnik D, Chauvin-Kimoff L, Farion KJ, Ali S, Lynch T, et al. Practice variations in the treatment of febrile infantsamong pediatric emergency physicians. Pediatrics. 2009;
124(2):439-45.
31. Pedersen TI, Roed C, Knudsen LS, Loft A, Skinhoj P, Nielsen SD. Fever of unknown origin: a retrospective study of 52 cases with evaluation of the diagnostic utility of FDG-PET/CT. Scand J
Infect Dis. 2012. 44:18–23.
32. Geijer H, Udumyan R, Lohse G, Nilsagård Y. Temperature measurements with a temporal scanner: systematic review and meta-analysis. BMJ Open. 2016; 6(3):e009509.
33. Erdem H, Baymakova M, Alkan S, Letaief A, Yahia WB, Dayyab F, Kolovani E, et al. Classical fever of unknown origin in 21 countries with different economic development: an international
ID-IRI study. Eur J Clin Microbiol Infect Dis. 2023;42(4):387-398.
34. Erdem H, Al-Tawfiq JA, Abid M, Yahia WB, Akafity G, Ramadan ME, Amer F, El-Kholy A, et al. Infectious causes of fever of unknown origin in developing countries: An international ID-IRI
study. J Intensive Med. 2023;4(1):94-100.
35. Wright WF, Wang J, Auwaerter PG. Investigator-Determined Categories for Fever of Unknown Origin (FUO) Compared With International Classification of Diseases-10 Classification of
Illness: A Systematic Review and Meta-analysis With a Proposal for Revised FUO Classification. Open Forum Infect Dis 2023;10:ofad104.
36. Mueller PS, Terrell CL, Gertz MA. Fever of unknown origin caused by multiple myeloma: a report of 9 cases. Arch Intern Med 2002; 162:1305
37. Manthiram K, Edwards KM, Long SS. Prolonged, Recurrent and Periodic Fever Syndromes. In: Long SS, Prober CG, Fischer M, editors. Principles and practice of pediatric infectious diseases
E-Book. Philadelphia, PA: Elsevier Health Sciences; 2022. p. 117–28.
38. Steenhoff A. Fever of Unknown Origin. In: Kliegman R, St Geme JW, Blum NJ, et al. Nelson textbook of pediatrics, 2020, Elsevier; Philadelphia, Pennsylvania,1397–1402.
39. Attard L, Tadolini M, De Rose DU, et al. Overview of fever of unknown origin in adult and paediatric patients, Clin Exp Rheumatol, 36 (Suppl 110), 2018, 10–24.
40. Wright WF, Mulders-Manders CM, Auwaerter PG, et al. Fever of unknown origin (FUO)– A call for new research standards and updated clinical management, Am J Med, 135 (2), 2022,
173–178.
41. Haidar G, Singh N. Fever of Unknown Origin. N Engl J Med 2022;386(5):463–77.
42. Török ME, Moran E, Cooke FJ. Imported fever. In: Oxford Handbook of Infectious Diseases and Microbiology. 2nd ed. Oxford: Oxford University Press, 2017:584-586
43. Knockaert DC, Vanderschueren S, Blockmans D. Fever of unknown origin in adults: 40 years on. J Intern Med 2003;253(3):263–75.
44. Chusid MJ. Fever of Unknown Origin in Childhood. Pediatr Clin North Am 2017; 64(1):205–30.
45. Centers for Disease Control and Prevention (CDC). Tick-borne Relapsing Fever. Centers for Disease Control and Prevention (CDC). Available at https://www.cdc.gov/relapsing-fever/index.
html. 2015 Sept 10; Accessed: 2022 Apr 25.
46. Warrell DA. Louse-borne relapsing fever (Borrelia recurrentis infection). Epidemiol Infect. 2019;147:e106.
47. Cunha BA. Fever of unknown origin: clinical overview of classic and current concepts. Infect Dis Clin North Am. 2007;21:867-915.
48. Kazanjian PH. Fever of unknown origin. Review of 86 patients treated in community hospital. Clin Infect Dis. 1992;15:968-973.
49. Cunha BA, Lortholary O, Cunha CB. Fever of unknown origin: a clinical approach. Am J Med. 2015;128(10): 1138.e1-1138.e15.
50. Wright WF, Kandiah S, Brady R, Shulkin BL, Palestro CJ, Jain SK. Nuclear Medicine Imaging Tools in Fever of Unknown Origin: Time for a Revisit and Appropriate Use Criteria. Clin Infect
Dis. 2024;78(5):1148-1153.
51. Kouijzer IJE, Mulders-Manders CM, Bleeker-Rovers CP, Oyen WJG. Fever of Unknown Origin: The Value of FDG-PET/CT. Semin Nucl Med. 2018;48(2):100-107.
52. Kushner I, Antonelli M. Acute Phase Reactans. [İnternet]. In: Furst DE, Case SM (eds). Uptodate [Accessed on January 2024]. https://www.uptodate.com/contents/acute-phase-reactants.
53. Black S, Kushner I, Samols D. C-reactive Protein. J Biol Chem 2004; 279:48487.
54. Marnell L, Mold C, Du Clos TW. C-reactive protein: ligands, receptors and role in inflammation. Clin Immunol 2005; 117:104.
55. Kushner I, Antonelli MJ. What should we regard as an “elevated” C-reactive protein level? Ann Intern Med 2015; 163:326.
56. Kushner I, Samols D, Magrey M. A unifying biologic explanation for “high-sensitivity” C-reactive protein and “low-grade” inflammation. Arthritis Care Res (Hoboken) 2010;62:442.
57. Casas JP, Shah T, Hingorani AD, et al. C-reactive protein and coronary heart disease: acritical review. J Intern Med 2008; 264:295.
58. Vanderschueren S, Deeren D, Knockaert DC, et al. Extremely elevated C-reactive protein. Eur J Intern Med 2006; 17:430.
59. Le Gall C, Désidéri-Vaillant C, Nicolas X. [Significations of extremely elevated C-reactive protein: about 91 cases in a French hospital center]. Pathol Biol (Paris) 2011; 59:319.
60. Krüger S, Ewig S, Papassotiriou J, et al. Inflammatory parameters predict etiologicpatterns but do not allow for individual prediction of etiology in patients with CAP: results from the German
competence network CAPNETZ. Respir Res 2009; 10:65.
61. Simon L, Gauvin F, Amre DK, et al. Serum procalcitonin and C-reactive protein levels asmarkers of bacterial infection: a systematic review and meta-analysis. Clin Infect Dis2004; 39:206.
62. Miller A, Green M, Robinson D. Simple rule for calculating normal erythrocyte sedimentation rate. Br Med J (Clin Res Ed) 1983; 286:266.
63. Reinhart WH. [Erythrocyte sedimentation rate–more than an old fashion?]. Ther Umsch2006; 63:108.
64. Etminan A, Seyed Askari SM, Naghibzade Tahami A, et al. Relationship between theserum levels of Vitamin D and inflammatory markers in ESRD patients. Acta Biomed2020; 91:e2020099.
65. Leff RD, Akre SP. Obesity and the erythrocyte sedimentation rate. Ann Intern Med 1986;105:143.
66. Jurado RL. Why shouldn’t we determine the erythrocyte sedimentation rate? Clin InfectDis 2001; 33:548.
67. Bleeker-Rovers CP, Vos FJ, de Kleijn E, et al. A prospective multicenter study on fever of unknown origin: the yield of a structured diagnostic protocol. Medicine (Baltimore) 2007; 86:26–38.
68. Palestro CJ, Brandon DC, Dibble EH, et al. FDG PET in Evaluation of Patients With Fever of UnknownOrigin: AJR Expert Panel Narrative Review. AJR Am J Roentgenol 2023; 221:151.
69. Kan Y, Wang W, Liu J, et al. Contribution of 18F-FDG PET/CT in a case-mix of fever of unknown origin andinflammation of unknown origin: a meta-analysis. Acta Radiol 2019; 60:716.
70. Wright WF, Auwaerter PG, Dibble EH, et al. Imaging a Fever-Redefining the Role of 2-deoxy-2-[18F]Fluoro-D-Glucose-Positron Emission Tomography/Computed Tomography in Fever of
Unknown Origin Investigations. Clin Infect Dis 2021; 72:1278-96.
71. Takeuchi M, Dahabreh IJ, Nihashi T, et al. Nuclear Imaging for Classic Fever of Unknown Origin: Meta-Analysis. J Nucl Med 2016; 57:1913.
72. Wright WF, Simner PJ, Carroll KC, Auwaerter PG. Progress Report: Next-Generation Sequencing, MultiplexPolymerase Chain Reaction, and Broad-Range Molecular Assays as Diagnostic
Tools for Fever ofUnknown Origin Investigations in Adults. Clin Infect Dis 2022; 74:924-32.
73. Søgaard KK, Farkas DK, Leisner MZ, et al. Fever of Unknown Origin and Incidence of Cancer, Clin Infect Dis, 75 (6), 2022, 968–974.
74. Minamimoto R. Optimal use of the FDG-PET/CT in the diagnostic process of fever of unknown origin (FUO): a comprehensive review. Jpn J Radiol 2022;40(11):1121–37.
75. Ordonez AA, Weinstein EA, Bambarger LE, et al. A systematic approach for developing bacteria-specific imaging tracers. J Nucl Med 2017; 58:144–50.
76. Lau CY, Martinez-Orengo N, Lyndaker A, et al. Advances and challenges in molecular imaging of viral infections. J Infect Dis 2023; 228: S270–80.
77. Berrevoets MAH, Kouijzer IJE, Aarntzen EHJG, Janssen MJR, De Geus-Oei LF, Wertheim HFL, Kullberg BJ, Oever JT, Oyen WJG, Bleeker-Rovers CP. 18F-FDG PET/CT optimizes treatment
in Staphylococcus aureus bacteremia and is associated with reduced mortality. J Nucl Med. 2017;58:1504–10.
78. Diemberger I, Bonfiglioli R, Martignani C, Graziosi M, Biffi M, Lorenzetti S, et al. Contribution of PET imaging to mortality risk stratification in candidates to lead extraction for pacemaker
or defibrillator infection: a prospective single center study. Eur J Nucl Med Mol Imaging.2019;46:194–205
79. Wang HY, Yang CF, Chiou TJ, et al. A “bone marrow score” for predicting hematological disease inimmunocompetent patients with fevers of unknown origin. Medicine (Baltimore) 2014;
93:e243.
80. Hot A, Jaisson I, Girard C, et al. Yield of bone marrow examination in diagnosing the source of fever of unknown origin. Arch Intern Med 2009; 169:2018.
81. de Kleijn EM, van Lier HJ, van der Meer JW. Fever of unknown origin (FUO). II. Diagnostic procedures in a prospective multicenter study of 167 patients. The Netherlands FUO Study Group.
Medicine (Baltimore) 1997;76:401–14.
82. Besson FL, Parienti JJ, Bienvenu B et al. Diagnostic performance of (1) (8) F-fluorodeoxyglucose positron emission tomography in giant cell arteritis: a systematic review and meta-analysis. Eur J
Nucl Med Mol Imaging 2011;38:1764–72.
83. Mourad O, Palda V, Detsky AS. A comprehensive evidence-based approach to fever of unknown origin. Arch Intern Med 2003;163:545–51.
84. Bleeker-Rovers CP, Bredie SJ, van der Meer JW et al. F-18-fluorodeoxyglucose positron emission tomography in diagnosis and follow-up of patients with different types of vasculitis. Neth J
Med 2003;61:323–9.
85. White NJ. The treatment of malaria. N Engl J Med 1996; 335:800.
86. Centers for Disease Control and Prevention. Treatment of Malaria: Guidelines For Clinicians (United States). Part 1: Reporting and Evaluation & Diagnosis. http://www.cdc.gov/malaria/
diagnosis_treatment/clinicians1.html (Accessed on January 04, 2021).
87. Griffith KS, Lewis LS, Mali S, Parise ME. Treatment of malaria in the United States: a systematic review. JAMA 2007; 297:2264.
88. Hopkins H. Laboratory tools for diagnosis of malaria [Internet]. In: Daily J, Baron EL (eds). Uptodate [Accessed on May 2024]. https://www.uptodate.com/contents/laboratory-tools-for-di-
agnosis-of-malaria.
89. Dong Y, Gao Y, Chai Y, et al. Use of Quantitative Metagenomics Next-Generation Sequencing to Confirm Fever of Unknown Origin and Infectious Disease. Front Microbiol 2022;13:931058.
90. Guo W, Feng X, Hu M, et al. The Application of Whole-Exome Sequencing in Patients With FUO. Front Cell Infect Microbiol 2021;11:783568.
91. Tounta V, Liu Y, Cheyne A, et al. Metabolomics in infectious diseases and drug discovery, Molecular Omics 2021; 17 (3): 376–393.