title: [The laboratory epidemiological study of the joint circulation of the influenza virus A subtypes A/H1N1/ and A/H3N2/ in Bulgaria].
abstract: The National Influenza Center of Bulgaria made the epidemiological analysis of the spread of influenza virus, type A, for the period of 11 years on the basis of mass laboratory investigations. Subtype A (H1N1) was found to be the main factor of epidemics in 1978 and 1982, while the epidemics of 1980, 1983, 1985, 1986, 1987 and 1988 were mainly caused by subtype A (H3N2). The data of laboratory and epidemiological studies indicated that after 20-year absence influenza virus A, subtype A (H1N1), was found again to circulate among the population of Bulgaria, and in 1978-1988 circulated simultaneously with the previous subtype A (H3N2). The simultaneous circulation of two subtypes of influenza virus was of great importance for the frequency, spread and duration of influenza epidemics.
authors.forename: Z
authors.initials: Z
authors.lastname: Nikolova
authors.forename: R
authors.initials: R
authors.lastname: Kotseva
mesh_terms: D002031:Bulgaria / Q000453:epidemiology; D004196:Disease Outbreaks / Q000706:statistics & numerical data; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D053122:Influenza A Virus, H3N2 Subtype; D009980:Influenza A virus / Q000145:classification* / Q000302:isolation & purification; D007251:Influenza, Human / Q000453:epidemiology / Q000382:microbiology*; D012621:Seasons; D012703:Serotyping
vernacular_title: Laboratorno-épidemiologicheskoe izuchenie sovmestnoĭ tsirkuliatsii podtipov A/H1N1/ i A/H3N2/ virusa grippa A v Bolgarii.