Diphyllobothrium latum and related species (the fish or broad tapeworm), the largest tapeworms that can infect people, can grow up to 30 feet long.SkipdirectlytositecontentSkipdirectlytopageoptionsSkipdirectlytoA-ZlinkParasites-DiphyllobothriumInfectionSectionNavigationCDCHomeFacebookTwitterLinkedInSyndicateParasites-DiphyllobothriumInfectionMinusRelatedPagesDiphyllobothriumlatumandrelatedspecies(thefishorbroadtapeworm),thelargesttapewormsthatcaninfectpeople,cangrowupto30feetlong.Whilemostinfectionsareasymptomatic,complicationsincludeintestinalobstructionandgallbladderdiseasecausedbymigrationofproglottids.Diagnosisismadebyidentificationofeggsorsegmentsofthetapeworminastoolsamplewithamicroscope.SafeandeffectivemedicationsareavailabletotreatDiphyllobothrium.Infectionsareacquiredbyeatingraworundercookedfish,usuallyfromtheNorthernHemisphere(Europe,newlyindependentstatesoftheFormerSovietUnion,NorthAmerica,Asia),butcaseshavealsobeenreportedinUgandaandChile.FishinfectedwithDiphyllobothriumlarvaemaybetransportedtoandconsumedinanyareaoftheworld.Adequatelyfreezingorcookingfishwillkilltheparasite.Image:L:SectionofanadultD.latumcontainingmanyproglottids.Thescolexwasnotpresentinthisspecimen.Scaleisincentimeters.R:ScolexofD.latum.(Credit:FloridaStatePublicHealthLaboratory,DPDx)clipboardiconAboutDiphyllobothriumlatum(andotherspecies)Mostcommonquestionsanswered...labiconBiologyStagesofparasitedevelopment...bookiconPublicationsRelatedarticlesandjournalentries…medicaliconResourcesforHealthProfessionalsWhatyouneedtoknow...Pagelastreviewed:September23,2020Contentsource:GlobalHealth,DivisionofParasiticDiseasesandMalariahomeDiphyllobothriumFrequentlyAskedQuestions(FAQs)BiologyResourcesforHealthProfessionalsPublicationsAboutOurDivisionSocial_govdgovDGetEmailUpdatesToreceiveemailupdatesaboutthispage,enteryouremailaddress:EmailAddressWhat'sthis?SubmitRelatedLinksParasitesA-ZIndexParasitesGlossaryNeglectedTropicalDiseasesLaboratoryDiagnosticAssistance[DPDx]ContactUsForHealthcareProviders,Eme