Hydatid cysts embedded in lungs.

Caribou lungs with hydatid cysts.

What causes hydatid disease?

Hydatid disease is caused by the larva of the tapeworm Echinococcus granulosus.

Lifecycle:  The tapeworm needs two hosts: a carnivore (eg. wolf or dog) and a herbivore (eg. caribou).  The tapeworm grows and lays eggs in the intestines of the carnivore. The eggs come out in the carnivore’s droppings and contaminate plants which are eaten by the herbivore.  The eggs hatch into larvae that travel to the herbivores lungs where they form cysts.  Carnivores become infected when they eat lungs that contain cysts.
 

Where does hydatid disease occur?

The adult tapeworm occurs in wolves and dogs without causing any harm.

The larval form or cyst occurs in moose, caribou, bison, wapiti (elk) and deer, and can occur in humans.

In the NWT and Nunavut, hydatid disease occurs commonly in moose and caribou.
 

What are the signs of hydatid disease?

Animals usually appear healthy and do not show any signs of disease.

In moose and caribou, the cysts have thick walls and are filled with a clear watery liquid. 

Cysts are usually found in the lungs, but can also occur in the liver or other organs. 

Cysts can be 2-20 cm in diameter, but most are 2-6 cm.

The surrounding tissue is usually normal.
 

How can I protect myself?

You can be infected from tapeworm eggs found in the droppings of wolves and dogs.

Wear gloves when handling scats from wolves or foxes.

The lung cysts in moose and caribou do not infect people.
 

Can I eat the meat?

Meat from infected animals is suitable for human consumption. 

Do not eat any tissues or organs containing cysts. 

Dogs and wolves can be infected from eating infected meat, and spread the disease to people.

Do not feed infected parts to dogs.
 

Samples to collect