Nematohelminthes (Round worms) Helminthology Phylum Phylum Platyhelminthes (Flat worms) + Nematohelminthes (Round worms) Class Trematoda (Flukes) Class Class Ceastoda (Tape worms) Nematoda Genus : Echinococcus Species : E. granulosus & E. multilocularis

Echinococcosis or Hydatidosis

1 Echinococcus granulosus cystic echinococcosis 2 Echinococcus multilocularis alveolar echinococcosis

Human Echinococcosis is caused by the larval stages of cestodes (tapeworms) of the genus Echinococcus Both have 3 proglottids, hooks and suckers

Echinococcus granulosis - The Hydatid Tapeworm Major pathology - hydatid cysts in the brain. Can grow to size of a coconut and contain as much as two liters of fluid. Pressure necrosis of tissue can result from larger cysts. Most commonly found in liver, but can develop anywhere, including in bone.

Adult Tapeworm Body is separated into 3 sections Scolex with 4 sukers & rostellum armed with double crown of 28-50 hooks

Ecchinococcus granulosus stages

Definitive Host/Intermediate Host Echinococcus granulosus: Definitive Host: dogs,Wolves and other carnivores Intermediate Host: mammals, including humans or herbivorous species( Sheep,Horses,Camels,Pigs) Echinococcus multilocularis: Definitive Host: mainly foxes but dogs, cats, coyotes and wolves also Intermediate Host: small rodents, rarely humans  

Geographic Distribution: E. granulosus Worldwide More frequent in rural, sheep raising areas E. multilocularis Occurs in northern hemisphere This includes central and northern Europe, Asia, and North America Most frequently found in northern states

Life Cycle of E granulosus

Symptoms: E. granulosus Can remain silent for years It is the enlarging cysts that cause symptoms in organs Hepatic involvement (abdominal pain, mass in the hepatic area, biliary duct obstruction) Pulmonary involvement (chest pain, Cough, hemoptysis) Brain, bone, and heart Rupture of cyst (fever, hives, pus, anaphylactic shock, and the cyst spreads throughout body cavity)

E. Multilocularis Affects the liver as a slow growing destructive tumor Abdominal pain, biliary obstruction, and sometimes metastatic lesions in lungs and brain are common symptoms Causes alveolar echinococcosis

Diagnosis Imagery Immunodiagnostic techniques Microscopy Hydatids are found during X-radiography, ultrasonography, CAT scans Immunodiagnostic techniques Generally less sensitive then imagery Microscopy Fluid aspirated from hydatid cyst will show many protoscolices

Infective stage: Egg Found in dog feces Resembles Taenia eggs

Imaging Studies: Plain radiography Ultrasound examination CT scaning MRI

Treatment Most effective and common type of treatment is surgery to remove the parasite mass Medication after surgery may be necessary to keep the cyst from recurring Drug of choice is albendazole for E. granulosus Drug of choice is albendazole and mebendazole for E. multilocularis

Prevention in Humans Minimize risk of egg ingestion Wash fruits and vegetables Wash hands frequently Avoid untreated water sources Do not handle wild carnivores or their carcasses Thoroughly cook meat before eating