Thread Lungworm

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What causes lungworm infections?

A variety of roundworm parasites are known as “lungworms” (eg. Dictyocaulus, Protostrongylus spp.).

Lifecycle: Adult worms are found in the lungs where they lay eggs that hatch into larvae. The larvae are coughed up, swallowed, and passed in the animals’ droppings. In some lungworms, the larvae are taken up by a snail or slug where they develop into an infective stage. The snails are then eaten by herbivores when feeding on plants. The larvae penetrate the animals intestines and travel to the lungs where they develop into adult worms. Other lungworms do not need a snail or slug host. The larvae develop into the infective stage on plants that are then eaten by the herbivore.

Lung of animal; thread lungworm infection not visible from exterior. (inset = close-up of thread lungworms).

Where do lungworm infections occur?

Lungworms are found in bison, muskox, caribou, reindeer, Dall’s sheep and snowshoe hares.

In the NWT and Nunavut, a number of different lungworms occur commonly in caribou and muskox.

What are the signs of lungworm infection?

Animals often appear healthy.

Animals with severe infections may cough and have difficulty breathing, especially after running.

They may be generally weak and thin, and have a harsh, dull hair coat.

When butchering, you may find adult worms or small round gray lumps of dead tissue up to 2 cm in diameter in the lungs.

Lungworms are white, threadlike worms that range in size from 1 - 8 cm long.

How can I protect myself?

You cannot become infected by lungworms.

Can I eat the meat?

Meat from infected animals is suitable for human consumption.

Samples to collect

Worms and/or parts of lungs with cysts, droppings.