Giant African Land Snails and the Rat Lungworm in Florida


Home / Giant African Land Snails and the Rat Lungworm in Florida

Achatina fulica carries the rat lungworm; the slime trail the snail leaves may contain infective larvae. Image by Sonel.SA: CC BY-SA 3.0

Florida’s Miami-Dade County is battling thousands of introduced giant African land snails: Achatina fulica. The snails grow to a hefty eight inches in length, and they reproduce right round the year. These giant snails eat plaster and stucco, as well as garden plants, and a percentage of them carry the rat lungworm, Angiostrongylus cantonensis. Unfortunately, humans sometimes catch A. cantonensis and suffer a form of parasitic meningitis.

What Is The Rat Lungworm? Angiostrongylus cantonensis and Eosinophilic Meningitis

The rat lungworm is a nematode (roundworm) that normally inhabits the pulmonary artery (the artery that carries blood from the heart to the lungs) and heart of rats. The adult worms are slender, growing to a length of just 1.5 to 2.5 centimeters. In many cases of  human infection, medical specialists suggest that the patient may have accidentally swallowed a slug.

Eating raw slugs and snails, either accidentally or on purpose, is only one way to catch A. cantonensis. Other animals sometimes harbor the parasite, including shellfish, shrimp and even frogs. Larvae may also be present in the slime trail that slugs and snails leave on garden vegetables, and this is a concern when giant snails are crawling all over your garden.

In humans, the rat lungworm causes a disease called eosinophilic meningitis, or angiostrongylosis. The patient suffers from a severe headache, fever, tingling sensations, stiff neck, and possibly vomiting. Most cases of rat lungworm infection are mild and the victim recovers completely; however, sometimes the illness progresses to coma and, rarely, death. Globally, hundreds of human cases of angiostrongylosis occur each year.

Dr. Trevor Smith, at the Florida Department of Agriculture and Consumer Services, told Decoded Science that the parasite is present in the Florida environment, but not at levels high enough to be a problem for humans. The giant African land snail could change things: “if we let the snail go,” Smith says, A. cantonensis “could become a real problem… If we can knock this population back, I think it will fade back into the background.”

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