Relapsing fever is a bacterial infection transmitted by a louse or tick. It is characterized by repeated episodes of fever.YouAreHere:Home→MedicalEncyclopedia→RelapsingfeverURLofthispage://medlineplus.gov/ency/article/001350.htmRelapsingfeverRelapsingfeverisabacterialinfectiontransmittedbyalouseortick.Itischaracterizedbyrepeatedepisodesoffever.CausesRelapsingfeverisaninfectioncausedbyseveralspeciesofbacteriaintheborreliafamily.Therearetwomajorformsofrelapsingfever:Tick-bornerelapsingfever(TBRF)istransmittedbytheornithodorostick.ItoccursinAfrica,Spain,SaudiArabia,Asia,andcertainareasinthewesternUnitedStatesandCanada.ThebacteriaspeciesassociatedwithTBRFareBorreliaduttoni,Borreliahermsii,andBorreliaparkerii.Louse-bornerelapsingfever(LBRF)istransmittedbybodylice.ItismostcommoninAsia,Africa,andCentralandSouthAmerica.ThebacteriaspeciesassociatedwithLBRFisBorreliarecurrentis.Suddenfeveroccurswithin2weeksofinfection.InTRBF,multipleepisodesoffeveroccur,andeachmaylastupto3days.Peoplemaynothaveafeverforupto2weeks,andthenitreturns.InLBRF,thefevercommonlylasts3to6days.Itisoftenfollowedbyasingle,milderepisodeoffever.Inbothforms,thefeverepisodemayendin"crisis."Thisconsistsofshakingchills,followedbyintensesweating,fallingbodytemperature,andlowbloodpressure.Thisstagemayresultindeath.IntheUnitedStates,TBRFoftenoccurswestoftheMississippiRiver,particularlyinthemountainsoftheWestandthehighdesertsandplainsoftheSouthwest.InthemountainsofCalifornia,Utah,Arizona,NewMexico,Colorado,Oregon,andWashington,infectionsareusuallycausedbyBorreliahermsiiandareoftenpickedupincabinsinforests.TheriskmaynowextendintothesoutheasternUnitedStates.LBRFismainlyadiseaseofthedevelopingworld.ItiscurrentlyseeninEthiopiaandSudan.Famine,war,andthemovementofrefugeegroupsoftenresultsinLBRFepidemics.SymptomsSymptomsofrelapsingfeverinclude:BleedingComaHeadacheJointaches,muscleachesNauseaandvomitingSaggingononesideoftheface(facialdroop)StiffneckSuddenhighfever,shakingchills,seizureVomitingWeakness,unsteadywhilewalkingEx