It is known that the incidence of respiratory tract infections such as cold and influenza show seasonal fluctuations and the peaks of respiratory illness occur in winter months. Around 33% of the seasonal increase in mortality is associated with infectious respiratory disease , and there is evidence that some of the seasonal growth in mortality associated with cardiovascular disease may be related to respiratory infection [2, 3]. This winter seasonality in deaths and illnesses has been shown for over 200 respiratory pathogens. There is a distribution of infectious pathogens among different age groups in Russia (Fig.1) .
Influenza was often detected in adults (55,8%) rather than in children aged 0-2 (15,2%), 3–6 (15,3%) and 7–14 (13,8%). ARVI of non-influenza etiology were more common among the youngest children (0-2 years). They got 72,5 and 62,8% of cases of BoV and RSV. As for adults the most common infections apart from influenza are CoV (33,3% of all cases) and RhV (25,7%) .
The structure of cases of infections detected from 2014 to 2016 confirmed the seasonal pattern of influenza infection: influenza À(H1N1)pdm09 – winter (80,0% of all cases), influenza À(H3N2) – winter-spring (60,8% – winter, 38,1% – spring) and influenza Â – winter-spring (31,8% winter and 66,0% – spring) (Figure 2). Autumn and summer are unlikely periods for influenza detection (0,01-2,0%). ARVI of non-influenza etiology demonstrate autumn-winter (AdV, PIV, BoV) or winter-spring patterns (RSV, CoV, MPV). Rhinovirus shows the biggest amount of cases in autumn .
Despite all these pathogens show some patterns, it is impossible to define the infectious agent by patients’ age, season period or symptoms. So for correct and effective therapy the pathogen has to be determined. The Central Russian Institute of Epidemiology has developed real-time PCR diagnostics kits for mentioned pathogens screening and identification.
Influenza A viruses are widely spread and might be rather dangerous, the virus causes epidemic and pandemic outbreaks. Each year there are about 600 mln cases of getting influenza A virus and over 150 thousand cases of hospitalization. There are 144 potential subtypes of influenza A, but the most dangerous subtypes of our time are H1N1, H2N2, H3N2 and H1N1swine. So the detection and typing of influenza A viruses are very important not only for correct treatment strategy but for control and early determination of new subtypes with potential pandemic features. Figure 3 demonstrates influenza A virus typing with our AmpliSens real-time PCR diagnostic kits.
Figure 3. Influenza A identification PCR diagnostic scheme.
Acute respiratory viral infections (ARVI) are rather common among respiratory tract infections in adults and children and kids under 15 more often get non-influenza infection. However it is important to identify the virus for correct treatment strategy choosing. Figure 4 demonstrates how our ARVI-screen AmpliSens real time PCR kit (R-V57-100-F(RG,iQ,Dt)-CE) is designed. It is developed for multiplex detection and identification of specific nucleic acid fragments of pathogens that cause acute respiratory viral infections – human Respiratory Syncytial virus (hRSv) RNA; human Metapneumovirus (hMpv) RNA; human Parainfluenza virus-1-4 (hPiv) RNA; ÎÑ43, Å229, NL63, and HKUI human Coronavirus (hCov) RNA; human Rhinovirus (hRv) RNA; human B, C, and E Adenovirus (hAdv) DNA; and human Bocavirus (hBov) DNA – in the clinical material (nasal and oropharyngeal swabs, sputum, aspirate of trachea, bronchoalveolar lavage, bronchial washing fluid, and autopsy material) by using real-time hybridization-fluorescence detection of amplified products.
Figure 4. ARVI-screen AmpliSens real-time PCR kit
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4. Karpova L. S., Volik K. M. Smorodintseva E. A. et al. The Impact of Influenza of Different Etiologies on other ARVI in Children and Adults in 2014 to 2016. Epidemiology and Vaccinal Prevention. 2018; 17 (6): 48–56 (In Russ.). https://doi: 10.31631/2073-3046-2018-17-6-35-47