Parasitic worms bury themselves in the brains of moose and elk – a new test can help diagnose these animals to prevent disease spread

The difficult-to-detect meningeal worm is spread by white-tailed deer and is a notorious killer of moose. AP Photo/Jim Cole, File

A moose in Minnesota stumbles onto the road. She circles, confused and dazed, unable to orient herself or recognize the danger of an oncoming semitruck. What kills her is the impact of 13 tons of steel, but what causes her death is more complicated. Tunneling through her brain is a worm that doomed both of them to die.

Commonly known as the brain worm, Parelaphostrongylus tenuis is a parasitic nematode that infects a large range of wild and domestic herbivores, such as moose and elk. The worm can migrate into the brain of unsuspecting hosts, where it may cause catastrophic disease and death.