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Echinococcus granulosus. Echinococcus granulosus. Hydatid disease Cosmopolitan Mediterranean countries Russian federation China North and East Africa Australia South America North America: Deep South and Far West. Echinococcus granulosus.
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Echinococcus granulosus • Hydatid disease • Cosmopolitan • Mediterranean countries • Russian federation • China • North and East Africa • Australia • South America • North America: Deep South and Far West
Echinococcus granulosus • ADULT MORPHOLOGY - small tapeworm - 3-6 mm long • consists of scolex, neck, immature proglottid, mature proglottid, and gravid proglottid
Carnivore Humans Herbivore
Pathogenesis • Hydatid cyst • Slow growth • Asymptomatic for years • Up to 20 years (unless in nervous system) • Pathology depends on • Location • Size • How many
Pathogenesis • Crowds host tissues • Destroys tissues-replaces with cyst • Grows continuously • 15 quarts of fluid • Millions of scolices • Rupture of the cyst fatal • Anaphylactic shock hydatid fluid (death) • In most herbivores, cysts do not keep growing
Unilocular hydatid cyst in the lung Note pressure effects exerted by cyst that crowds and destroys lung tissue
Diagnosis • Physical imaging • MRI • CT scan • Ultrasound • X-ray • Serodiagnosis
Treatment • Surgery • Preoperative chemotherapy-albendazole • Protoscolicidal compounds • Ethanol • Saline • Formalin • Recurrence • 50% • Undetected cysts • Inadequate removal • Mebendazole • 48% of cysts
Epidemiology • How do people get infected? • How do eggs get into environment? • How do we ingest them?
Epidemiology • Human-Dog • Herbivores: Sheep, goats, camels, rabbit • Sheep raising areas • Offal
Epidemiology • Human-Dog contact
Epidemiology • Human-wildlife contact
Complex • Echinococcus granulosus comprises multiple species • Life cycle patterns • Host specificity • Development Rate • Antigenicity • Transmission dynamics • Chemotheraputic drug response • Pathology
Control • Sheep vaccine successful
Life Cycle of Echinococcus multilocularis • 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 multilocularis Alveolar hydatid cyst in a mouse - cyst metastasizes from the liver to fill the body cavity
Echinococcus multilocularis • Liver • Cyst multilocular hydatid • External budding • Extend processes throughout tissues • Cirrhosis of liver • Thinner membrane • Metastasis • Advanced cases
Echinococcus multilocularis • Not easily operable • timing • Chemotherapy • Praziquantel can increase growth • Mebendazole and albendazole given throughout the life of the patient. • retards growth • Not easily treatable
Echinococcus multilocularis • Fox tapeworm • Europe, Asia, Americas, New Zealand
Echinococcus multilocularis This 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.
Epidemiology • Increasing in Europe • Up to 1980’s only in France, Switzerland, Germany, and Austria • Spreading throughout Europe.
Epidemiology • Increase in fox infection • Increase in human infection • Still rare • Switzerland and Germany • Antirabies vaccines • Increased fox abundance • Movement of foxes • Encroachment on urban areas • Contact with domestic dogs
Hymenolepis • Hymenolepis diminuta • Rare in humans • 90 cm • Model tapeworm • Hymenolepis nana • “Dwarf tapeworm” 40 mm long • Common in humans • 97.3% children in Moscow • 1% children in SE US Cysticercoid
Hymenolepis nana D A 1 B 2 3 4 C
Pathogenesis and Treatment • Similar to Adult species of Taenia • Praziquantel
Dipylidiumcaninum • Most common tapeworm of dogs • Cats, humans • 2 sets of reproductive organs
Gravid proglottids shed Dog eats flea Infective stage?
Pathogenesis and Treatment • Similar to Adult species of Taenia • Praziquantel