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Giant snails that can cause meningitis prompt quarantine in Florida

According to the Florida Department of Agriculture and Consumer Services, this is “one of the most damaging snails in the world.” 
Dep't Of Agriculture Warns Of Arrival Of Giant African Land Snails In U.S.
Giant African land snails are shown to the media as the Florida Department of Agriculture and Consumer Services announces it has positively identified a population of the invasive species. Joe Raedle / Getty Images

After being eradicated twice since the '70s, an invasive species of snail is once again posing a threat to central Florida residents.

Giant African land snails have been found in the New Port Richey area of Pasco County, and they're known to carry a meningitis-causing parasite called rat lungworm. Meningitis refers to the swelling of the membranes that protect the brain and spinal cord, and it can be deadly.

Late last month, the Florida Department of Agriculture and Consumer Services (FDACS) confirmed the presence of giant African land snails, which it describes as "one of the most damaging snails in the world." The FDACS has set up a quarantine zone and eradication program to deal with the threat.

"These snails could be devastating to Florida agriculture and natural areas as they cause extensive damage to tropical and subtropical environments," explained a notice on the FDACS website, adding that the pests consume more than 500 varieties of plants.

The eradication program will treat properties in the quarantine zone with a metaldehyde-based molluscicide, aka snail bait, and residents are encouraged to report sightings of the species to the FDACS at 1-888-397-1575.

As far as the threat to humans, most people infected with rat lungworm fully recover without treatment, according to the Centers for Disease Control and Prevention. That said, the infection can cause a rare type of meningitis, which has no specific treatment and can lead to serious complications, such as paralysis, coma and death. Parasites that cause meningitis usually infect animals, but people can become infected by eating infected animals or other contaminated foods.

If you live in or travel to an area where the parasite is found, the CDC recommends preventing an infection with rat lungworm by:

  • Not ingesting raw or undercooked snails and slugs, freshwater shrimp, land crabs, frogs, monitor lizards, or potentially contaminated vegetables or vegetable juice
  • Removing snails, slugs and rats found near houses and gardens
  • Thoroughly washing hands and utensils after preparing raw snails or slugs
  • Throughly washing vegetables if eaten raw

Giant African land snails are illegal to import or possess in the U.S. without a permit — for good reason. The giant African land snail starts reproducing as young as 4 months old and can lay thousands of eggs over the multiple years that it's alive. They can travel long distances by clinging to vehicles or trash, and if they find themselves in an unfavorable environment, they can bury themselves in soil and survive for up to year.

Florida's last widespread eradication efforts against the giant African land snail began after the species was detected in Miami-Dade County in 2011. It wasn’t until September 2021 that the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS), which worked in conjunction with the FDACS, declared the snails successfully eradicated. The snails were first detected in Florida in 1969 and eradicated in 1975.