Clinical and epidemiological aspects of West Nile fever in the Republic of Tatarstan
DOI: 10.32364/2587-6821-2025-9-12-1
I.V. Nikolayeva1, V.A.Trifonov2, T.A. Savitskaya2, A.Kh. Bulatova1, M.R. Gataullin3, Yu.A. Tyurin1,2, E.V. Agafonova1,2, I.D. Reshetnikova2,4, G.Sh. Isayeva1,2, M.A. Patyashina5
1Kazan State Medical University, Kazan, Russian Federation
2Kazan Research Institute of Epidemiology and Microbiology of Rospotrebnadzor, Kazan, Russian Federation
3A.F. Agafonov Republic Clinical Infectious Disease Hospital, Kazan, Russian Federation
4Kazan (Volga Region) Federal University, Kazan, Russian Federation
5Rospotrebnadzor Department of the Republic of Tatarstan, Kazan, Russian Federation
Aim: to conduct a clinical and epidemiological analysis of West Nile fever (WNF) cases and to investigate the seroprevalence of the population to West Nile virus (WNV) in the Republic of Tatarstan (RT).
Materials and Methods: a serological monitoring study (Enzyme-Linked Immunosorbent Assay (ELISA)) was conducted between 2012 and 2023 to detect specific IgG to WNV in the blood sera of donors. A total of 3178 donor blood samples, collected after the end of the epidemic season, were tested from residents of 29 municipal entities of RT. For the clinical and epidemiological analysis of WNF cases, a retrospective follow-up study was performed, analyzing the medical records of 87 patients hospitalized at GAUZ "RKIB" during 2023–2024. Laboratory diagnosis of WNF was performed using Polymerase Chain Reaction (PCR) (blood, cerebrospinal influenzaid (liquor), urine) and ELISA detecting specific IgM and IgG (at an interval of 7–10 days). ELISA for antibodies to tick-borne encephalitis virus was performed to exclude cross-reactions.
Results: according to literature, two imported cases of WNF were registered in RT in 2010 and 2018. Subsequent sporadic cases among RT residents not associated with travel outside Russia were registered: 4 cases in 2011, 3 in 2012, 8 in 2023, and 80 cases in 2024. All sporadic cases between 2010 and 2023 were identified in residents of five districts of Kazan. Among those affected in 2024, residents of Kazan predominated — 58 (72.5%) individuals — while 22 (27.5%) cases were registered among residents of 7 districts of RT. The mean age of the patients was 50.6±16.1 years, with males more commonly affected (64.8%). The disease manifested as a influenza-like form in 62% of cases, and neuroinvasive forms were diagnosed in 38% of cases. Meningoencephalitis primarily developed in patients older than 65 years (74%). Fatal outcomes occurred in 4 (4.6%) elderly patients (63–75 years) diagnosed with meningoencephalitis. Based on long-term average data (2012–2023), 4.9% of residents across 28 municipal entities possess specific IgG.
Conclusion: the research results indicate the formation of a natural focus of WNF within the territory of RT. It is necessary to strengthen epidemiological surveillance measures for mosquito populations and vector control measures in areas of potential infection foci.
Keywords: West Nile fever, incidence, clinical manifestations, PCR diagnostics, ELISA diagnostics, epidemiological process, WNV seroprevalence, serological monitoring.
For citation: Nikolayeva I.V., V.A.Trifonov, Savitskaya T.A., Bulatova A.Kh., Gataullin M.R., Tyurin Yu.A., Agafonova E.V., Reshetnikova I.D., Isayeva G.Sh., Patyashina M.A. Clinical and epidemiological aspects of West Nile fever in the Republic of Tatarstan. Russian Medical Inquiry. 2025;9(12):832–839 (in Russ.). DOI: 10.32364/2587-6821-2025-9-12-1
ABOUT THE AUTHORS:
Irina V. Nikolaeva — Dr. Sc. (Med.), Professor, Head of the Department of Infectious Diseases, Kazan State Medical University; 49, Butlerova str., Kazan, 420012, Russian Federation; ORCID iD 0000-0003-0104-5895
Vladimir A. Trifonov — Leading Researcher, Laboratory of Epidemiology and Natural Focal Infections, Kazan Research Institute of Epidemiology and Microbiology of Rospotrebnadzor; 67, B. Krasnaya str., Kazan, 420015, Russian Federation; ORCID iD 0000-0002-1810-1825
Tatyana A. Savitskaya — C. Sc. (Bio.), Head of the Laboratory of Epidemiology and Natural Focal Infections, Kazan Research Institute of Epidemiology and Microbiology of
Rospotrebnadzor; 67, B. Krasnaya str., Kazan, 420015, Russian Federation; ORCID iD 0000-0002-6229-0387
Asiya Kh. Bulatova — C. Sc. (Med.), Assistant Professor of the Department of Infectious Diseases, Kazan State Medical University; 49, Butlerova str., Kazan, 420012, Russian Federation; ORCID iD 0000-0002-6167-1882
Marat R. Gataullin — Chief Medical Officer of the A.F. Agafonov Republic Clinical Infectious Disease Hospital; 83, build. 2, Pobedy аve., Kazan, 420140, Russian Federation; ORCID iD 0000-0002-4522-3094
Yury A. Tyurin — Dr. Sc. (Med.), Head of the Laboratory of Immunology and Allergen Development, Kazan Research Institute of Epidemiology and Microbiology of Rospotrebnadzor; 67, B. Krasnaya str., Kazan, 420015, Russian Federation; Associate Professor of the Department of Biochemistry, Kazan State Medical University; 49, Butlerova str., Kazan, 420012, Russian Federation; ORCID iD 0000-0002-2536-3604
Elena V. Agafonova — C. Sc. (Med.), Head of the Laboratory, doctor of the Clinical Diagnostic Laboratory, Kazan Research Institute of Epidemiology and Microbiology of Rospotrebnadzor; 67, B. Krasnaya str., Kazan, 420015, Russian Federation; Associate Professor, Kazan State Medical University; 49, Butlerova str., Kazan, 420012, Russian Federation; ORCID iD 0000-0002-4411-8786
Irina D. Reshetnikova — C. Sc. (Med.), Director of the Kazan Research Institute of Epidemiology and Microbiology of Rospotrebnadzor; 67, B. Krasnaya str., Kazan, 420015, Russian Federation; Associate Professor, Kazan (Volga Region) Federal University; 18, build. 1, Kremlevskaya str., Kazan, 420008, Russian Federation; ORCID iD 0000-0002-3584-6861
Guzel Sh. Isaeva — Dr. Sc. (Med.), Deputy Director for Innovative Development, Kazan Research Institute of Epidemiology and Microbiology of Rospotrebnadzor; 67, B. Krasnaya str., Kazan, 420015, Russian Federation; Head of the Department of Microbiology named after Academician V.M. Aristovsky, Kazan State Medical University; 49, Butlerova str., Kazan, 420012, Russian Federation; ORCID iD 0000-0002-1462-8734
Marina A. Patyashina — Dr. Sc. (Med.), Corresponding Member of the Academy of Sciences of the Republic of Tatarstan, Head of the Rospotrebnadzor Department of the Republic of Tatarstan; 30, B. Krasnaya str., Kazan, 420111, Russian Federation; ORCID iD 0000-0002-6302-3993
Contact information: Vladimir A. Trifonov, e-mail: vattrifonov@mail.ru
Financial Disclosure: no authors have a financial or property interest in any material or method mentioned.
There is no conflict of interest.
Received 20.08.2025.
Revised 12.09.2025.
Accepted 07.10.2025.
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