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