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Scientistshavefoundthestrongestevidenceyetthatavirusisto______foramysteriousillnessthatcanquickly______children.

Theveryrarecondition,calledacuteflaccidmyelitisorAFM,issimilartothepoliodisease.ThefirstreportsofthediseasecamefromtheAmericanstateofCaliforniain.Sincethen,theU.S.hasexperiencedanincreasinglybiggeroutbreakeveryotheryear,fromlatesummerintoautumn.

DoctorshavelongbelievedthatcertainvirusesknownasenterovirusescausedAFM.Buttheydidnothaveenoughevidencetoproveit.

Soresearcherstriedsomethingnew.Theycheckedpatientsspinalfluidforsignstheimmunesystemhadfoughtaninvadingvirus.Childrenwhogotsickhadantibodiesthattargetenteroviruses.

Dr.MichaelWilsoniswiththeUniversityofCalifornia,SanFrancisco.Hehelpedleadtheresearch.Hesaidtheevidencedidnotprovetheiridea.ButitwasapowerfulsignenterovirusescauseAFM.

HisteamreportedthefindingsinthepublicationNatureMedicine.

Studyco-writerDr.RileyBoveiswiththesameuniversityasWilson.BovessondevelopedAFMatagefour.Henoted,"Ifyoudonthaveacause,youcanthaveavaccine."BoveaddedthatWilsondeveloped"agoodenoughmicroscope,inasense,tofindthingstheysuspectedwerethere."

AboutcasesoftheillnesshavebeenconfirmedintheU.S.since.Casesincreasedthatyear,inandin.Onlyafewwerereportedintheyearsinbetween.Sofar,therehavebeen22casesthisyear.