Theinfluenzainfectionisanacutefeverishvirusinfectionoftherespiratorytract.Theinfectionmostlyresultsfromadropletinfectionandappearsasanepidemicorpandemy.Thevirusanditstoxincanleadtoaseriousinflammationofthebronchialmucosaandadamageofthevessels.Afteranincubationtimeof1to3daysthesymptomsappearsuddenly:Followedbyafastraiseoftemperature,oftenaccompaniedbyshivering,theleADIngsymptomofcatarrhalinflammationappears,contributingtotheclinicalcourseofpainfuldrycough,tracheitis,laryngitisandfrequentlyarhinitisandconjunctivitis.
TheInfluenzavirusesformavirusgroupwithprincipallysimilarmorphological,chemicalandBIOLOGicalfeatures.ThetypesA,BandCweredefined,includingmanyothervariants.ThedifferentiationofthetypeswillbepossIBLebythedifferentantigenicityoftheirnucleoproteinsandtheirmatrixproteinswithtype-specificantigenicity.However,theessentialimmunodominantantigensarethehemagglutininandtheneuraminidase.Botharesurfaceantigensandshowapermanentchangeoftheirantigenicity,calleddriftorshift.TheappearancenewInfluenzaepidemicsandpandemiesarefacilitatedbyantigenvariABIlity.
ThedeterminationoftheInfluenzatype(A,B,andC)givesboththeclinicianandepidemiologistimportantindicationsforfurtheractions.ThusInfluenzaBoftenleadstoaseriousclinicalcourseandanepidemicspreadofthevirus.Similarly,duringanInfluenzaAepidemic,theepidemiologicalimportanceandderivedmeasurementsoftheprotectionoftheindividualareimportant.