Analysis of peculiarities of seasonal influenza in residents of the Altai territory

• Igor P. Saldan
• Karbysheva Nina V.
• Bobrovskiy Evgeniy A.
• Nikonorova Marina A.
• Matros Olga I.
• Kiushkina Irina N.
• Mozharova Darya A.

Abstract

The aim was to study the clinical features of infection caused by influenza a virus in residents of the Altai territory in the epidemic seasons 2015-2018, taking into account the antigenic characteristics of the pathogen.

Material and methods. Retrospective analysis of 117 case histories of patients with the Laboratory-confirmed diagnosis of influenza. A comparative assessment of the clinical picture of the disease, the results of laboratory and instrumental studies were conducted.

Results and discussion. The etiological structure of influenza epid seasons of 2015-2018 years was dominated by subtypes of influenza A, of which A(H3N2) was >80%. Pandemic influenza virus A(H1N1pdm09) showed epidemic activity only in season of 2015-2016 years. Influenza symptoms were different, depending on the strain of the virus that caused the disease. The mild course was observed in 35.9% of patients. The proportion of influenza A(H3N2) virus in patients with mild course was 71.4%. In most cases (48.7%) the disease was of moderate severity and was caused by influenza А virus (H1N1pdm09), (H1N1), (H3N2) in 38.6, 43.9, and 17.5% cases respectively. Severe forms of influenza were diagnosed in 18 (15.4%) patients. In 12 cases of these, pandemic strain of influenza A virus was isolated (H1N1pdm09), in 4 - A(H1N1), in 1 patient - A(H3N2). In 13 (11.1%) patients, influenza was pneumonia-related and was caused by the following subtypes of type A virus: A(H1N1pdm09) pandemic (12 patients) and seasonal A(H1N1) influenza viruses. All patients with severe and complicated forms of influenza were not vaccinated.

Keywords:influenza, etiological structure, clinical manifestations

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