Despite the efforts of practical medicine and virology, influenza viruses remain the most important pathogens affecting human and animal health. Swine are exposed to infection with all types of influenza A, B, C, and D viruses. Influenza viruses have low pathogenicity for swine, but in the case of co-infection with other pathogens, the outcome can be much more serious, even fatal. Having a high zoonotic potential, swine play an important role in the ecology and spread of influenza to humans. In this study, we review the state of the scientific literature on the zoonotic spread of swine influenza A viruses among humans, their circulation in swine populations worldwide, reverse zoonosis from humans to swine, and their role in interspecies transmission. The analysis covers a long period to trace the ecology and evolutionary history of influenza A viruses in swine. The following databases were used to search the literature: Scopus, Web of Science, Google Scholar, and PubMed. In this review, 314 papers are considered: n = 107 from Asia, n = 93 from the U.S., n = 86 from Europe, n = 20 from Africa, and n = 8 from Australia. According to the date of publication, they are conditionally divided into three groups: contemporary, released from 2011 to the present (n = 121); 2000–2010 (n = 108); and 1919–1999 (n = 85).

Analyze clinical samples collected and determine the etiology of viral pathogens and the dynamics of their spread. Acute respiratory viral infections remain one of the key health problems worldwide. They constitute etiologically independent diseases, with similar clinical infection manifestations and a single mechanism for the transmission of pathogens. 4712 nasopharyngeal swabs were collected from people before and during the COVID-19 pandemic with acute respiratory infections that tested negative for COVID-19 and were examined in this study. The collected samples were screened by a real-time polymerase chain reaction on a Rotor-Gene Q6 plex instrument. Statistical processing of the results, tabular, and graphical data were analyzed in the MS Excel. The largest number of the nasopharyngeal swabs were collected from children under 17 years of age (60.75%). In 702 samples (9.85%) pathogens of respiratory infections of non-influenza etiology were detected, including adenovirus, bocavirus, coronavirus, metapneumovirus, paramyxovirus types I–IV, respiratory syncytial virus, and rhinovirus. At the same time, both before and during the COVID-19 pandemic, different influenza virus variants co-circulation (A/H1N1, A/H3N2, and type B) were discovered, with a predominance of viruses with the antigenic formula A/H1N1. The results of the study indicate the need for continuous monitoring of the viral pathogens spread, which will expand the existing knowledge of the viral etiology of respiratory diseases and highlight the importance of viruses in the respiratory infections occurrence.

Here, we report the coding-complete genome sequence of a clinical sample of influenza virus obtained from a pig at a livestock farm in Karaganda, Central Kazakhstan, during a pig study in 2020. Isolate A/Swine/Karaganda/04/2020 (H1N1) belongs to clade 1A.3.2.2 lineage 1A, which includes the 2009 H1N1 pandemic strains.

Objective: To conduct serological studies of influenza infection rate during an epidemic. Methods: The retrospective study was conducted at the Research and Production Centre for Microbiology and Virology, Almaty, Kazakhstan, and comprised data, including blood samples, from patients with symptoms of acute respiratory viral infection, bronchitis and pneumonia during 2018-21 from various healthcare institutions in the Almaty region. Serological tests on blood serums were carried out sing haem agglutination inhibition assay and enzyme-linked immunosorbent assay. Data was analysed using Graph Pad Prism 9. Results: Of the 779 blood samples, 392(50.3%) came from women and 387(49.7%) from men. The overall age range was 0-80 years. Serological analyses using haem agglutination inhibition assay showed the presence of anti-hemagglutinins against pandemic A(H1N1)pdm09 virus in 292(37.5%) samples, influenza A/H3N2 virus in 340(43.6%) and type B virus in 53(6.8%). Antibodies against two subtypes of influenza A virus and type B virus were simultaneously identified in 25(3.2%) cases, whereas against influenza A (H1N1+H3N2) viruses in 69(8.9%). In enzyme-linked immunosorbent assay, antibodies against influenza A/H1N1pdm virus were detected in 108(13.9%) cases, against A/H3N2 virus in 105(13.5%) and type B virus in 65(8.3%). Antibodies simultaneously against two subtypes of influenza A virus were identified in 46(5.9%) of blood serums, and against influenza A and B viruses in 60(7.7%). Conclusion: Co-circulation of influenza A and B viruses was observed, confirming the role of influenza viruses in the epidemic process. Key Words: Virus, Influenza, Antigen, Serum, Diagnosis.

This study described the results of a surveillance program monitoring circulation of influenza A viruses among domestic pigs (Sus domesticus) in Kazakhstan during 2018-2021. PCR data derived from 2,513 samples (nasopharyngeal swabs) collected from swine on large pig complexes and peasant farms located in different regions of Kazakhstan revealed that about 5% of samples were positive for influenza A virus RNA. This result suggested low levels of influenza A virus circulation in Kazakhstan. Subtyping of a set of samples revealed that the main strains circulating in 2018-2019 were A/H1N1 and A/H3N2.Surveillance conducted in 2020-2021 identified only A/H1N1 viruses in swine. The PCR data were confirmed by isolation of six strains: five influenza A/H1N1 viruses and one A/H3N2 virus.

Respiratory tract infections cause serious morbidity and mortality and are a major public health problem. The objective of our study was detection of the prevalence of viral respiratory diseases in the territory of Kazakhstan during the epidemic period of 2018–2024. The presence of respiratory viruses in nasopharyngeal swabs was analyzed using real-time polymerase chain reaction. The level of specific antibodies in the blood serum was determined by hemagglutination inhibition assay and enzyme-linked immunosorbent assay. In rtRT-PCR, patients were diagnosed with non-influenza viral respiratory tract infections as well as influenza viruses A(H1N1), A(H3N2), and B. Antibodies were detected against A(H1N1)pdm09, influenza A(H3N2), and influenza B viruses and with simultaneous detection of both viruses. The circulation of influenza A(H3N2) viruses belonging to the 3C.2a1b.2a.2a.3a.1 clade was confirmed by whole-genome sequencing. According to the results, in the period 2018–2024, the spread of influenza A and B viruses and non-influenza respiratory tract infections was observed. The data of this study confirm the role of known causative agents of epidemic infection and indicate the need to continue monitoring their spread in Kazakhstan, which may add to the general quality of the health system.