Echinococcus multilocularis in Ontario

Signs and symptoms

Signs and symptoms of alveolar echinococcosis will typically appear within 5-15 years after ingestion of eggs of Echinococcus multilocularis. They tend to occur in the late phase of the infection when large portions of the liver are infiltrated by the parasite. Signs and symptoms may include:

• Enlarged liver

• Upper abdominal pain

• Weight loss

• Jaundice

Recovery is highly dependent on when the infection is diagnosed and proper treatment. 

 

 

Transmission

Humans become infected with alveolar hydatid cysts by consumption of Echinococcus multilocularis eggs. This transmission may occur by:

• Ingestion of eggs from contaminated hands after handling an infected fox, coyote, dog, or cat

• Ingestion of eggs from contact with contaminated soil or plants 

 

 

Prevention

• Wash hands with warm soapy water immediately after handling foxes, coyotes, dogs, and cats

• Do not allow your dog or cat to consume wild rodents

• Avoid contact with the feces of wild foxes and coyotes 

• Teach everyone in the family the importance of proper hand hygiene 

 

 

Diagnosis

Diagnostic imaging techniques [e.g. Ultrasonography (Ultrasound), Computed Tomography (CT) scan, and Magnetic Resonance Imaging (MRI)] are used to visualize the parasitic mass in the liver. Serological (blood) tests are used to confirm the parasitic infection. 

If people test positive on the serological test it is important to appreciate that most do not develop alveolar hydatid cysts. In those that do, there is a good chance that the larval growths can be controlled by use of drugs and potentially surgery.

 

 

Treatment

Treatment options for alveolar echinococcosis in people depends on the time of diagnosis.
Complete surgical removal of the parasitic cyst by is possible in most cases diagnosed in the early stages of infection. Often, however, cases are diagnosed late and not all of the parasitic mass can be removed.

After surgery, antiparasitic drugs are required for at least 2 years. These antiparasitic drugs stop the parasite from growing but do not usually kill the parasite. Typically, the chemotherapy slows down the growth of the parasite, allowing for the patient’s immune system to eliminate the infection.