Diphyllobothrium spp. eggs are oval or ellipsoidal and range in size from 55 to 75 µm by 40 to 50 µm. There is an operculum at one end that can ...[LastModified:][Diphyllobothriumlatum][Diphyllobothriumspp.]MicroscopyEggsDiphyllobothriumspp.eggsareovalorellipsoidalandrangeinsizefrom55to75µmby40to50µm.Thereisanoperculumatoneendthatcanbeinconspicuous,andattheopposite(abopercular)endisasmallknobthatcanbebarelydiscernible.Theeggsarepassedinthestoolunembryonated.ABA,B: EggsofD.latuminaniodine-stainedwetmount.NotetheknobattheabopercularendinFigureB.ImagescourtesyoftheOregonStatePublicHealthLaboratory.CDC,D: EggsofDiphyllobothriumlatum.AdultsAdultsofDiphyllobothriumspp.maybe4-10metersinlength. Thescolexiselongated,1mmby3mm,withtwoshallow,longitudinalgrooves.Asproglottidsmature,theymaybreakofffromthestroblia,inlengthscontainingfewtomanysegments. Proglottidsarebroaderthantheyarelongandrangefrom2to4mmlongby10to12mmwide. Theuterusiscoiledinrosetteappearanceandthegenitalporeisatthecenteroftheproglottid. Therearenumeroustestesthatappearinthelateralfieldsofeachproglottid.EFE: SectionofanadultD.latumcontainingmanyproglottids. Thescolexwasnotpresentinthisspecimen. ImagecourtesyoftheFloridaStatePublicHealthLaboratory.F: Close-upofafewoftheproglottidsfromthespecimeninFigureE,showingtherosette-shapeduterusatthecenterofeachproglottid.GHG,H: Carmine-stainedproglottidsofD.latum,showingtherosette-shapedovaries.II: ScolexofD.latum.JKJ,K:EggswithintheproglottidsofDiphyllobothriumsp.,observedinanintestinalbiopsyspecimenstainedwithhematoxylinandeosin(H&E). Imagestakenat500xmagnification. ImagescourtesyoftheUniversityofWashingtonMedicalCenter,Seattle,WA.