Dibothriocephalus latus (=Diphyllobothrium latum), the “broad fish tapeworm”, is usually assumed to be the most common agent of human ...SkipdirectlytositecontentSkipdirectlytopageoptionsSkipdirectlytoA-ZlinkDPDx-LaboratoryIdentificationofParasitesofPublicHealthConcernSectionNavigationCDCHomeFacebookTwitterLinkedInSyndicateDiphyllobothriasisMinusRelatedPages[Dibothriocephaluslatus(=Diphyllobothriumlatum)][Dibothriocephalusspp.][Adenocephaluspacificus]ParasiteBiologyImageGalleryLaboratoryDiagnosisResourcesCausalAgentsSeveralmembersofthecestode(tapeworm)familyDiphyllobothriidaeareknowntoinfecthumans.Thesepseudophyllideancestodeshaveascolexbearingbothria(grooves),insteadofsuckersasinthecyclophyllideancestodes(thegroupincludingnearlyallhuman-infectingspecies).Allspeciesassociatedwithhumandiphyllobothriidinfectionshavemarineoraquaticlifecyclesandtransmissionoccursviaingestionofundercookedfish.Recentresearchincorporatingmorphologicandmoleculardatahasledtothere-classificationandre-namingofmostofthehuman-infectingdiphyllobothriids.Dibothriocephaluslatus (=Diphyllobothriumlatum),the“broadfishtapeworm”,isusuallyassumedtobethemostcommonagentofhumandiphyllobothriasis.However,itispossiblethatmanyhistoricalcaseswerefalselyattributedtothisspecies.Dibothriocephalusnihonkaiense(=Diphyllobothriumnihonkaiense),Dibothriocephalusdendriticus(=Diphyllobothriumdendriticum),Diphyllobothriumstemmacephalum(=Diphyllobothriumstemmacephalum;=Diphyllobothriumyonagoense),Diphyllobothriumbalaenopterae(=Diplogonoporusgrandis;=Diplogonoporusbalaenoptera),andAdenocephaluspacificus(=Diphyllobothriumpacificum)arealsoknowntoinfecthumans.Sporadiccasereportsexistinvolvingseveralotherdiphyllobothriidspecies,althoughsomeofthespeciesidentificationsinthesereportsareofquestionablevalidity.LifeCycleViewLargerEggsarepassedunembryonatedinfeces.Underappropriateconditions,theeggsmature(approximately18to20days)andyieldoncosphereswhichdevelopintoacoracidia.Afteringestionbyasuitablecrustacean(firstintermediatehost)thec