A Brain-Invading Worm Spread By Rats and Snails Has Reached California

A brain-invading worm spread by rats and snails is making inroads into the United States. A study this week seems to show the nematode Angiostrongylus cantonensis, a.k.a. the rat lungworm, is now making itself cozy in California. Veterinary and zoo experts in San Diego detailed their discovery Thursday in the journal Emerging Infectious Diseases (disclaimer: there are graphic images from the report included below). They identified lungworm infections in a zoo-dwelling Parma wallaby as well as in nearby rat and opossum populations. The worm has likely become an endemic threat to both animals and people living in the state, the researchers say. “Our findings indicate [locally acquired] infections, which pose a substantial risk to humans and accidental vertebrate hosts,” they wrote. Like many parasites, the rat lungworm has a complicated life cycle. Adult worms mature, mate, and lay eggs in a rodent’s lungs. These eggs hatch into larvae and are coughed out into the rodent’s throat, then swallowed back in through the digestive tract, finally ending up in poop. A snail or slug then eats the contaminated poop (or gets infected through close contact). Once inside the snail, the larvae ent