Brainworm (Meningeal Worm)


Commonly Infected Wildlife

In Missouri, deer and elk can be infected.

Is This Animal Infected?

Brainworm is a common parasite in white-tailed deer.

Infected deer rarely have any clinical signs.

Infected elk often leave their herd, and they may display circling behavior and/or a head tilt.

In elk, the disease is often fatal, although there may be short periods of remission when the animal appears quite normal.

Can I Get It?

No. There is no known risk to humans.

How bad can it get?

There is no known risk to humans.

Symptoms in humans

There is no known risk to humans.

Protect Myself and Others

The meat of infected animals is safe for human consumption.

Safe for Pets?

Dogs and cats are not known to be affected, but the parasite may infect sheep, goats, guinea pigs, llamas, and alpacas.


What Causes It?

The parasitic roundworm Parelaphostrongylus tenuis. The roundworm larvae develop in snails and slugs. Deer and elk are infected when they inadvertently ingest snails and slugs while grazing.