life cycle and pathogenesis
Last reviewed 12/2021
Echinococcus is asymptomatic in dogs, but can cause a variety of problems in humans.
Infection is by ingestion of canine tapeworm eggs which hatch in the duodenum. The released embryos cross the mucosal membrane and travel to the portal blood supply, and thence to the liver. The primary site of infection is the liver; however they may affect any organ in the body.
The hydatid itself is a large parasitic cyst which grows slowly and assymptomatically. Eventually they can have an effect on other structures - pressure effects, or rupturing. The cysts themselves can become infected with bacteria with subsequent problems.