Epidemiološki i virološki nadzor influence i influenci slične bolesti u Sloveniji

The number of patients with acute respiratory infections rises sharply shortly after the influenza virus appears in population. Consequently, the hospitalization and mortality rates increase. Several indicators may be used to measure the burden-of-illness caused by the influenza virus: incidence rate of influenza-like illness (ILI) or acute respiratory illness (ARI), crude or cause-specific mortality rate, sick-live or monitoring the over the counter (OTC) medication sales. Two indicators have been measured in Slovenia since 1999: the ILI and ARI incidence rates in approximately 4% of the population. Multiplex Reverse Transcription-Polymerase Chain Reaction (RT-PCR) was used as a screening method for the detection of influenza viruses, respiratory syncytial virus (RSV), adenoviruses and enteroviruses in nasal and/or throat swabs. All positive samples were further propagated in the corresponding cell culture line. RT-PCR was used for fast determination of hemaglutinins (H1, H3) and neuraminidases (N1, N2) of influenza A viruses. The antigenic subtype of the samples isolated on the cell culture was determined by means of a hemaglutination inhibition assay and confirmed in the WHO European Reference Centre for Influenza. In the 2004/2005 season, the ILI incidence rate was at highest in weeks 5, 6 and 7 of the year 2005, when it reached its peak value (392/100,000). The highest ARI incidence rate was recorded in the period from 31st January to 6th February, and remained elevated for the following two weeks. Samples were taken from 793 patients with clinical signs of ILI. The influenza A or B virus was detected in 15.2% of patients. One third of the influenza A cases were of the H1N1 subtype, while the others were H3N2. Enteroviral infection was relatively common in the past season (15.8% of patients). The influenza isolates in Slovenia were similar to those in other European countries and belonged to: A/H3N2/California/7/2004 (A/H3N2/Fujian/441/2002-like viruses), A/H1N1/New Caledonia/20/99 and B/Jiangsu/10/03 (B/Shaghai/361/2002-like viruses). The dominant influenza virus in Europe and the USA was influenza A H3N2. The ARI and/or ILI incidence rates were higher in most European countries (including Slovenia) compared to previous seasons.Broj pacijenata s akutnom dišnom zarazom naglo se povećava nakon što se u populaciji počinje javljati virus influence. Kao posljedica toga javlja se povećana stopa hospitalizacije i mortaliteta. Nekoliko pokazatelja može se rabiti za mjerenje pojave popratnih bolesti vezanih uz influencu: stopa pojavnosti influenci slične bolesti ili akutne dišne bolesti, stopa nespecifičnog i specifičnog mortaliteta, bolovanje ili promatranje povećane potrošnje lijekova. Dva su pokazate-lja mjerena u Sloveniji od 1999.: pojava bolesti slične influenci i stopa pojave akutne dišne bolesti na oko 4% populacije. Lančana reakcija polimerazom uz prethodnu reverznu transkripciju (RT-PCR) bila je rabljena kao pregledna metoda za dokaz virusa influence, respiratornog sincicijskog virusa, adenovirusa i enterovirusa u obriscima nosa i/ili žrijela. Svi pozitivni uzorci bili su zatim nacijepljeni na odgovarajuće stanične linije. RT-PCR je bio upotrijebljen za brzo određivanje hemaglutinina (H1, H3) i neuraminidaze (N1, N2) virusa influence A. Antigenski podtipovi izdvojenih virusa na staničnim kulturama određeni su pomoću testa inhibicije hemaglutinacije te potvrđeni u Europskom referentnom centru za influencu Svjetske zdravstvene organizacije. U sezoni 2004./2005. stopa pojavnosti bolesti slične influenci bila je najveća u 5., 6. i 7. tjednu 2005., kada je dostigla svoj vrhunac (392/100000). Najviša incidencija akutne dišne bolesti ustanovljena je u razdoblju od 31. siječnja do 6. veljače i na toj je razini ostala sljedeća dva tjedna. Uzorci su bili uzeti od 793 bolesnika s kliničkim znakovima bolesti slične influenci. Virus influence A i B bio je dokazan u 15,2% pacijenata. Trećina slučajeva influence bila je uzrokovana podtipom H1N1 dok su ostali bili uzrokovani podtipom H3N2. Enterovirusne infekcije bile su relativno česte u prošloj sezoni (u 15,8% pacijenata). Izolati virusa influence bili su slični onima izdvojenima u drugim europskim zemljama i pripadali su serotipovima A/H3N2/California/7/2004 (A/H3N2/Fujian/441/2002-slični virusi), A/H1N1/New Caledonia/20/99 and B/Jiangsu/10/03 (B/Shanghai/361/2002-slični virusi). Dominantni virus influence u Europi i SAD-u bio je podtip A H3N2. Pojavnost akutne dišne bolesti i/ili influenci slične bolesti bila je veća u usporedbi s prethodnom sezonom u većini europskih zemalja (uključujući i Sloveniju)