Seasonalinfluenzaischaracterizedbyasuddenfevercoughheadachemuscleandjointpainsorethroatandrunnynose.Mostpeoplerecoverfromfeverand 1 symptomswithinaweekwithoutrequiringmedicalattention.Butinfluenzacan 2 severeillnessordeathinpeopleathighrisk.Thetimefrominfectiontoillnessisabouttwodays.
Yearlyinfluenzaepidemicscan 3 affectallagegroupsbutthehighestriskofcomplicationsoccuramongchildrenyoungerthanagetwoadultsage65orolderandpeopleof 4 agewithcertainmedicalconditionssuchaschronicheartlungkidneyliverbloodormetabolicdiseasesorweakenedimmunesystems.
Seasonalinfluenza 5 easilyandcansweepthroughschoolsnursinghomesorbusinessesandtowns.Whenan 6 personcoughsinfecteddropletsgetintotheairandanotherpersoncanbreathethem 7 andbeexposed.Theviruscanalsobespreadbyhandsinfectedwiththevirus. 8 transmissionpeopleshouldcovertheirmouthandnosewithatissuewhencoughingand 9 theirhandsregularly.
Drugsforinfluenzaare 10 insomecountriesandeffectivelypreventandtreattheillness.Someinfluenzavirusesdevelop 11 totheantiviralmedicineslimitingtheeffectivenessoftreatment.
Influenzaepidemicsoccur 12 duringautumnandwinterintemperateregions.Illnessesresultinhospitalizationsanddeathsmainlyamonghigh-riskgroups.Worldwidetheseannualepidemicsresultinaboutthreetofivemillion 13 ofsevereillnessandabout250000to500000deaths.
Influenzacancauseseriouspublichealthandeconomicproblems.In 14 countriesepidemicscanresultinhighlevelsofworkerabsenteeismandproductivity 15 . 16 mostpeoplerecoverfromabout(轮)ofinfluenzatherearelargenumbersofpeoplewhoneedhospitaltreatmentandmany 17 diefromthediseaseeveryyear. 18 isknownabouttheeffectsofinfluenzaepidemicsindevelopingcountries.
Themost 19 waytopreventthediseaseorsevereoutcomesfromtheillnessisvaccination.Vaccinationisespeciallyimportantforpeopleathigherriskofseriousinfluenzacomplicationsandforpeoplewholivewithorcare 20 highriskindividuals.
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