Echinococcus granulosusEchinococcus granulosus
Echinococcus granulosusEchinococcus granulosusADULT MORPHOLOGY - small tapeworm - 3-6 mm long
• consists of scolex, neck, immature proglottid, mature proglottid, and gravid proglottid
Echinococcus granulosusEchinococcus granulosus
• Hydatid diseaseHydatid disease
• CosmopolitanCosmopolitan– Mediterranean countriesMediterranean countries– Russian federationRussian federation– ChinaChina– North and East AfricaNorth and East Africa– AustraliaAustralia– South AmericaSouth America– North America: Deep South and Far WestNorth America: Deep South and Far West
Carnivore
HerbivoreHumans
10-30 scolices per brood capsule
PathogenesisPathogenesis• Hydatid cystHydatid cyst
• Slow growthSlow growth
• Asymptomatic for yearsAsymptomatic for years
• Up to 20 years (unless in Up to 20 years (unless in nervous system)nervous system)
• Pathology depends on Pathology depends on – LocationLocation– SizeSize– How manyHow many
PathogenesisPathogenesis• Crowds host tissuesCrowds host tissues
• Destroys tissues-replaces with cystDestroys tissues-replaces with cyst
• Grows continuouslyGrows continuously– 15 quarts of fluid15 quarts of fluid– Millions of scolicesMillions of scolices
• Rupture of the cyst fatalRupture of the cyst fatal– Anaphylactic shock hydatid fluid (death)Anaphylactic shock hydatid fluid (death)
• In most herbivores, cysts do not keep In most herbivores, cysts do not keep growinggrowing
Unilocular hydatid cyst in the lung
Note pressure effects exerted by cyst that crowds and destroys lung tissue
Hydatid CystHydatid Cyst
DiagnosisDiagnosis• Physical imagingPhysical imaging
– MRIMRI– CT scanCT scan– UltrasoundUltrasound– X-rayX-ray
• SerodiagnosisSerodiagnosis
Hydatid Cyst of Hydatid Cyst of Echinococcus Echinococcus granulosusgranulosus
TreatmentTreatment
• SurgerySurgery– Preoperative chemotherapy-albendazolePreoperative chemotherapy-albendazole– Protoscolicidal compoundsProtoscolicidal compounds
• EthanolEthanol• SalineSaline• FormalinFormalin
• RecurrenceRecurrence– 50%50%– Undetected cystsUndetected cysts– Inadequate removalInadequate removal
• MebendazoleMebendazole– 48% of cysts48% of cysts
EpidemiologyEpidemiology
• How do people get infected?How do people get infected?
• How do eggs get into environment?How do eggs get into environment?
• How do we ingest them?How do we ingest them?
EpidemiologyEpidemiology
• Human-DogHuman-Dog
• Herbivores: Sheep, goats, camels, rabbitHerbivores: Sheep, goats, camels, rabbit
• Sheep raising areasSheep raising areas
• OffalOffal
EpidemiologyEpidemiology
• Human-Dog contactHuman-Dog contact
EpidemiologyEpidemiology
• Human-wildlife contactHuman-wildlife contact
Echinococcus granulosusEchinococcus granulosus
ComplexComplex
• Echinococcus granulosusEchinococcus granulosus comprises comprises multiple speciesmultiple species– Life cycle patternsLife cycle patterns– Host specificityHost specificity– Development RateDevelopment Rate– AntigenicityAntigenicity– Transmission dynamicsTransmission dynamics– Chemotheraputic drug responseChemotheraputic drug response– PathologyPathology
ControlControl
• Sheep vaccine successfulSheep vaccine successful
Echinococcus multilocularisEchinococcus multilocularis
Life Cycle ofLife Cycle of Echinococcus Echinococcus multilocularismultilocularis
1. Adult tapeworm occurs in intestine of foxes.
Dogs, cats, and coyotes can also serve as definitive hosts.
• Adult is small - 1-2 mm long
Echinococcus multilocularisEchinococcus multilocularis
Alveolar hydatid cyst in a mouse - cyst metastasizes from the liver to fill the body cavity
Alveolar Hydatid Cyst
• LiverLiver• Cyst multilocular Cyst multilocular
hydatidhydatid• External buddingExternal budding• Extend processes Extend processes
throughout tissuesthroughout tissues• Cirrhosis of liverCirrhosis of liver• Thinner membraneThinner membrane• MetastasisMetastasis
– Advanced casesAdvanced cases
Echinococcus multilocularisEchinococcus multilocularis
Echinococcus multilocularisEchinococcus multilocularis
• Not easily operableNot easily operable– timingtiming
• Chemotherapy Chemotherapy – Praziquantel can increase growthPraziquantel can increase growth– Mebendazole and albendazole given throughout Mebendazole and albendazole given throughout
the life of the patient. the life of the patient. • retards growthretards growth
• Not easily treatableNot easily treatable
Echinococcus multilocularisEchinococcus multilocularis
• Fox tapewormFox tapeworm
• Europe, Asia, Americas, New ZealandEurope, Asia, Americas, New Zealand
Echinococcus multilocularisEchinococcus multilocularisThis species has recently been reported in the upper Midwest (North and South Dakota, Minnesota, Iowa, Nebraska, southern Wisconsin, and Indiana). Recently identified in Illinois, Ohio and Missouri.
EpidemiologyEpidemiology
• Increasing in EuropeIncreasing in Europe• Up to 1980’s only in France, Switzerland, Germany, and Up to 1980’s only in France, Switzerland, Germany, and
Austria Austria • Spreading throughout Europe.Spreading throughout Europe.
EpidemiologyEpidemiology
• Increase in fox infectionIncrease in fox infection• Increase in human infectionIncrease in human infection
– Still rareStill rare
• Switzerland and GermanySwitzerland and Germany– Antirabies vaccinesAntirabies vaccines– Increased fox abundanceIncreased fox abundance– Movement of foxesMovement of foxes– Encroachment on urban areasEncroachment on urban areas– Contact with domestic dogsContact with domestic dogs
HymenolepisHymenolepis
HymenolepisHymenolepis• Hymenolepis diminutaHymenolepis diminuta
– Rare in humansRare in humans
– 90 cm90 cm
– Model tapewormModel tapeworm
• Hymenolepis nanaHymenolepis nana– ““Dwarf tapeworm” 40 mm longDwarf tapeworm” 40 mm long
– Common in humansCommon in humans
– 97.3% children in Moscow97.3% children in Moscow
– 1% children in SE US1% children in SE US
Cysticercoid
Hymenolepis nanaHymenolepis nanaA
B
C
D 1
2
34
Pathogenesis and TreatmentPathogenesis and Treatment
• Similar to Adult species of Similar to Adult species of TaeniaTaenia
• PraziquantelPraziquantel
Dipylidium caninumDipylidium caninum
Dipylidium caninumDipylidium caninum
• Most common tapeworm of Most common tapeworm of dogsdogs
• Cats, humansCats, humans
• 2 sets of reproductive organs2 sets of reproductive organs
Gravid proglottids
shed
Dog eats flea
Infective stage?
DiagnosticsDiagnostics
Pathogenesis and TreatmentPathogenesis and Treatment
• Similar to Adult species of Similar to Adult species of TaeniaTaenia
• PraziquantelPraziquantel