Main Article Content



Influenza is viral fever with the main symptoms of the respiratory tract like cough, fever, breathlessness, nasal discharge, sore throat & myalgia. Pandemic 2009 H1N1 influenza A was the virus that presented a significant public health threat on a global scale. This prospective study was undertaken to analyse the prevalence of the influenza virus in patients with a severe acute respiratory infection (SARI) and also to determine the demographic characteristics and seasonal variations.


This was a hospital-based prospective study done in the Department of Microbiology, Silchar Medical College & Hospital, Silchar for 1 year from June 2021 to May 2022. Respiratory specimens were tested for Influenza virus by one step real-time reverse transcription polymerase chain reaction (RT-PCR).


In real-time PCR, the influenza virus was detected in 6 out of 85 SARI patients (7%). Of 6 total positives, 4(67%) were influenza A and 2(33%) were influenza B. Among 4 influenza A positive cases, 3(75%) were influenza A (H1N1) pdm09 and 1(25%) was seasonal influenza A (H3N2). The highest percentage of positivity (50%) was detected in the age group of 15-29 years. The most common symptoms among the positive influenza cases were fever (100%), cough (88%), and breathlessness (56%). Other associated symptoms were sore throat (63%), nasal discharge (75%), and myalgia (75%).


This study clearly shows that influenza is an important cause of severe acute respiratory infection. It also suggests the need for continuous effective surveillance of influenza viruses to detect cases and control outbreaks. Early intervention and proper management of influenza virus cases are required to curb the disease burden.


SARI, RT-PCR, Influenza A (H1N1) pdm09, Influenza A (H3N2).

Article Details

How to Cite
Debadatta Dhar Chanda, Chhandasree Biswas, & Supriya Upadhyay. (2023). Prevalence of Influenza Virus in Patients with Severe Acute Respiratory Infections (SARI). Journal of Evolution of Medical and Dental Sciences, 12(2), 42–47.


  1. World Health Organization. Acute Respiratory Infections: Influenza. 2007. Available from:
  2. Simonsen L. The global impact of influenza on morbidity and mortality. Vaccine 1999;17:S3-10.
  3. Influenza (seasonal), World Health Organization 2009. Available from: fs211/en/index.html, accessed on January 24, 2010.
  4. Ortiz JR, Sotomayor V, Uez OC, et al. Strategy to enhance influenza surveillance worldwide. Emerg Infect Dis 2009;15(8):1271-8.
  5. Rambaut A, Pybus OG, Nelson MI, et al. The genomic and epidemiological dynamics of human influenza A virus. Nature 2008;453(7195):615-9.
  6. Choudhry A, Singh S, Khare S, et al. Emergence of pandemic 2009 influenza A H1N1, India. Indian J Med Res 2012;135(4):534-7.
  7. Falagas ME, Cholevas NV, Kapaskelis AM, et al. Epidemiological aspects of 2009 H1N1 influenza: the accumulating experience from the Northern Hemisphere. Eur J Clin Microbiol Infect Dis 2010;29(11):1327-47.
  8. Charu V, Chowell G, Palacio-Mejia LS, et al. Mortality burden of the A/H1N1 pandemics in Mexico: a comparison of deaths and years of life lost to seasonal influenza. Clin Infect Dis 2011;53(10):985-93.
  9. Ministerio de Salud (CL). Guia de vigilancia intensificada de las infecciones respiratorias agudas graves. Santiago: MINSAL 2016. Available from: wp-content/uploads/2017/10/GuiaVigilancia-Intensificada-IRA-version2016.
  10. Rao BL. Epidemiology and control of Influenza. National Journal of India 2003;16(3):143-9.
  11. Wang W, Ren P, Mardi S, et al. Design of multiplexed detection assays for identification of avian influenza a virus subtypes pathogenic to humans by SmartCycler real-time reverse transcription-PCR. J Clin Microbiol 2009;47(1):86-92.
  12. Ellis JS, Zambon MC. Molecular diagnosis of influenza. Rev Med Virol 2002;12(6):375-89.
  13. Storch GA. Essentials of diagnostic virology. New York: Churchill Livingstone Inc 2000.
  14. Belshe RB, Walker R, Stoddard JJ, et al. Influenza vaccine-live. In: Plotkin S, Orenstein W, Offit P, eds. Vaccines. 5th edn. Philadelphia: Saunders Elsevier 2008:291-309.
  15. Dangi T, Jain B, Singh AK, et al. Influenza virus genotypes circulating in and around Lucknow, Uttar Pradesh, India, during post pandemic period, August 2010--September 2012. Indian J Med Res 2014;139(3):418-26.
  16. Chadha MS, Broor S, Gunasekaran P, et al. Multi site Virological Influenza Surveillance in India: 2004-2008. Influenza and Other Respiratory Viruses 2012;6(3):196-203.
  17. Broor S, Krishnan A, Roy DS, et al. Dynamic Patterns of Circulating Seasonal and Pandemic A(H1N1)pdm09 Influenza Viruses From 2007–2010 in and around Delhi, India. PLoS One 2012;7(1):e29129.
  18. Palani N, Sistla S. Epidemiology and phylogenetic analysis of respiratory viruses from 2012 to 2015 – A sentinel surveillance report from union territory of Puducherry, India, Clinical Epidemiology and Global Health 2020;8(4):1225-35.
  19. Mukherjee A, Roy T, Agrawal AS, et al. Prevalence and epidemiology of pandemic H1N1 strains in hospitals of Eastern India. J Pub Health and Epidemiol 2010;2(7):171-4.
  20. Koul PA, Khan UH, Asad R, et al. Contribution of influenza to acute exacerbations of chronic obstructive pulmonary disease in Kashmir, India, 2010-2012. Influenza Other Respir Viruses. 2015;9(1):40-2.
  21. Dayakar S, Pillai HR, Thulasi VP, et al. Comparative Study of Molecular Approaches for the Detection of Influenza Virus from Patient Samples Using Real-time PCR: Prospective Disease Burden Study in Kerala (India) from 2010 to 2016. Curr Infect Dis Rep 2018;20(8):24.
  22. Alam ST, Rajbongshi G, Rabha D, et al. Recent trends of pandemic 2009 H1N1 virus infection in Guwahati, Assam: a prospective study. Indian J Microbiol Res 2019;6(1):18-21.
  23. Biswas DK, Kaur P, Murhekar M, et al. An outbreak of pandemic influenza A (H1N1) in Kolkata, West Bengal, India, 2010. Indian Journal of Medical Research 2012;135(4):529-33.
  24. Roy Mukherjee T, Chanda S, Mullick S, et al. Spectrum of respiratory viruses circulating in eastern India: Prospective surveillance among patients with influenza‐like illness during 2010–2011. Journal of Medical Virology 2013;85(8):1459-65.
  25. Choudhry A, Singh S, Khare S, et al. Emergence of pandemic 2009 influenza A H1N1, India. Indian J Med Res 2012;135(4):534-7.
  26. Sidhu SK, Singh K, Devi P, et al. Clinical-epidemiological profile and diagnosis of Influenza A H1N1 cases by real time RT-PCR at a tertiary care institute of India: The war is not over yet. Asian Pac J Health Sci 2016;3(3):120-5.
  27. Li YQ, Qian Q, Fung LQ, et al. Epidemiological characteristics of 420 influenza A(H1N1) cases confirmed in the early stage of the epidemic in Mainland China. Zhonghua Liu Xing Bing Xue Za Zhi 2009;30(11):1102-5.
  28. Roy T, Agrawal AS, Mukherjee A, et al. Surveillance and Molecular characterization of human influenza B viruses during 2006–2010 revealed co-circulation of Yamagata-like and Victoria-like strains in eastern India. Infect Genet Evol 2011;11:1595-601.
  29. Krammer F. The human antibody response to influenza A virus infection and vaccination. Nat Rev Immunol 2019;19(6):383-97.
  30. Sakhiya AJ, Tanna K, Vegad MM, et al. Virological surveillance of influenza virus in acute respiratory infection. Indian J Microbiol Res 2018;5(3):299-302.
  31. Agrawal AS, Sarkar M, Chakrabarti S, et al. Comparative evaluation of real-time PCR and conventional RT-PCR during a 2 year surveillance for influenza and respiratory syncytial virus among children with acute respiratory infections in Kolkata, India. J Med Microbiol 2009;58(Pt 12):1616-22.
  32. Mukherjee A, Roy T, Agrawal AS, et al. Prevalence and epidemiology of pandemic H1N1 strains in hospitals of Eastern India. J Pub Health and Epidemiol 2010;2(7):171-4.

Most read articles by the same author(s)