Echinococcosis is a zoonotic disease (transmitted from animals to humans) caused by the larval stage (hydatid cyst) of tapeworms. Eggs are excreted in the faeces of infected dogs and foxes and can be ingested by humans either by close contact with these animals or through contaminated food.

Cystic echinocccosis (CE), also known as hydatid disease, is caused by infection with the larval stage of Echinococcus granulosus, a ~2–7 millimeter long tapeworm found in dogs (definitive host) and sheep, cattle, goats, and pigs (intermediate hosts).

Symptoms

• Pain in the upper right part of the abdomen (liver cyst)
• Increase in size of the abdomen due to swelling (liver cyst)
• Bloody sputum (lung cyst)
• Chest pain (lung cyst)
• Cough (lung cyst)
• Severe allergic reaction (anaphylaxis) when cysts break open.

Their medical importance lies in the infection of humans by the larval stage of the parasites, predominantly including Echinococcus granulosus, which is the causative agent of cystic echinococcosis (CE) and Echinococcus multilocularis, which causes alveolar echinococcosis (AE).

Echinococcosis is an infectious disease caused by the larval form of the genus Echinococcus. Two of the parasite species may cause severe disease in humans: Echinococcus granulosus and Echinococcus multilocularis. The liver is the most frequently involved organ in patients with echinococcosis.

Echinococcus granulosus definitive hosts are wild and domestic canids. Natural intermediate hosts depend on genotype. Intermediate hosts for zoonotic species/genotypes are usually ungulates, including sheep and goats (E. granulosus sensu stricto), cattle (“E.

E. granulosus is classified as a eukaryote because its cells contain a nucleus and membrane bound organelles. Members of the Animalia kingdom are all multicellular and heterotrophic.

Echinococcus granulosus [this species causes hydatid disease in mammals, including humans] Parasite morphology: Tape-worms form three different developmental stages: eggs; larvae; and adults. Adult E. granulosus worms are small (2-6mm long) and have a scolex with only three attached segments.

Several strains of E. granulosus have been identified, and all but two are noted to be infective in humans. The lifecycle of E. granulosus involves dogs and wild carnivores as a definitive host for the adult tapeworm….

Echinococcus granulosus, which causes cystic echinococcosis, is a cestode whose life cycle involves dogs and other canids as definitive hosts for the intestinal tapeworm and domestic and wild ungulates as intermediate hosts for the tissue-invading metacestode, which is the larval stage of the tapeworm (Fig. 281.1).

Tapeworms
Hydatid worm/Class

E. granulosus is classified as a eukaryote because its cells contain a nucleus and membrane bound organelles. Members of the Animalia kingdom are all multicellular and heterotrophic. Moreover, they all lack cell walls and at some point in their life cycle they are all motile, these are also characteristics of E.

Introduction  Echinococcus granulosus, also called hydatid worm belongs to class Cestoda  It causes cystic echinococcosis in livestock and humans being intermediate hosts and parasitize the small intestines of adult canids  It is a zoonotic disease  Definitive hosts are carnivorous predators like dogs, wolves, foxes and lions.

Echinococcus granulosus infections remain silent for years before the enlarging cysts cause symptoms in the affected organs. Hepatic involvement can result in abdominal pain, a mass in the hepatic area, and biliary duct obstruction. Pulmonary involvement can produce chest pain, cough, and hemoptysis.

Too few cases of E. oligarthrus have been reported for characterization of its clinical presentation. Echinococcus granulosus in tissue. Upon ingestion of eggs by the human host, the oncospheres migrate from the intestinal lumen to other body sites via circulation and develop into hydatid cysts.

Echinococcus multilocularis affects the liver as a slow growing, destructive tumor, often with abdominal pain and biliary obstruction being the only manifestations evident in early infection. This may be misdiagnosed as liver cancer. Rarely, metastatic lesions into the lungs, spleen, and brain occur. Untreated infections have a high fatality rate.