MIAMI—Floridians have grown accustomed to invasions of exotic creatures, like the Burmese pythons slithering throughout the Everglades. But residents here are especially grossed out by the latest arrivals: giant African land snails that grow as long as eight inches, chew through plants, plaster and stucco, and sometimes carry a parasite that can infect humans with a nonlethal strain of meningitis.
The gastropods are among the most dangerous in the world, agriculture officials say. They each have male and female reproductive organs and can lay 1,200 eggs a year, allowing them to proliferate rapidly. Thousands of them have infested at least five separate neighborhoods in the Miami area.
Homeowners who discover the creatures in their yards often find them disgusting. The snails' engorged bodies extend far from their shells, and they eat so ravenously that they leave trails of excrement on walls and the ground.
They eat stucco, chew through plants and can even carry meningitis. Destructive giant African snails are taking over Miami, one neighborhood at a time. WSJ's Arian Campo-Flores reports.
"I'm traumatized," said Liliam Hernandez last week, as she and her husband recounted how they had discovered a five-inch specimen behind their house a while earlier. She said she was so distraught at the sight of the slimy mollusk that she got a migraine and had to lie down.
"She's so panicked that she doesn't want to go out anymore," said her husband, Jaime Saravia.
Federal and state agriculture officials have responded with a large-scale eradication effort. They've deployed 70 people to hunt for the pests house by house in the affected areas. Since the snails were first detected on Sept. 8, workers have collected about 10,000 of them from 114 properties.
"This is a menace to human health, to the environment and to our economy," says Adam Putnam, commissioner of the Florida Department of Agriculture and Consumer Services, who toured one of the overrun neighborhoods last week.
It's not the first time the snails have plagued Miami. In 1966, a boy brought home three of them from a trip to Hawaii and kept them in a terrarium, says Richard Gaskalla, director of the agriculture department's division of plant industry. Eventually, the child's grandmother released them into the garden. "They have a tendency to not smell good after a while," says Mr. Gaskalla.
The creatures propagated wildly. It took authorities almost a decade to wipe them out, with a campaign that cost more than $1 million and snared 18,000 snails.
This time around, officials learned of the infestation from two sisters, Aida and Zoila Gutierrez, who live around the corner from Ms. Hernandez. This spring, they noticed the snails, which feed on 500 types of plants, gradually overtaking their backyard. "They were driving us crazy," says Zoila Gutierrez.
Last month, they spotted an agriculture inspector who happened to be in the neighborhood on a routine visit and called him over. As soon as the agriculture department confirmed that the offenders were giant African snails, it launched the eradication campaign.
Originally from east Africa, the snails can now be found in the Pacific Rim, Hawaii and several Caribbean islands. It's illegal to bring them into the U.S. without a permit from the U.S. Department of Agriculture, and no permits have been issued for years, says Mr. Gaskalla.
Though authorities say they still don't know the origin of the current outbreak, they're investigating the possibility that the snails were smuggled in for religious rituals.
Last year, law enforcement raided the Hialeah, Fla., home of Charles L. Stewart, who claimed to be an African priest, according to a search warrant affidavit filed in state court. Among the items found on the property, which is in one of the infested neighborhoods, were seven live snails and 57 eggs, according to a document submitted by a state investigator.
Mr. Stewart, who was known as "El Africano" or "Oloye Ifatoku," allegedly smuggled the snails into the country in his luggage and kept them in a wooden box in his backyard, feeding them lettuce, according to investigators' interviews with three informants who dealt with Mr. Stewart, the affidavit says. An African priestess he knew also brought in the mollusks, secreted under her dress, according to the affidavit.
The informants said Mr. Stewart used the creatures in healing rituals, cracking the tips of their shells and pouring snail juice into devotees' mouths, the affidavit says. One informant reported losing weight and developing a painful stomach lump after receiving 10 snail treatments, according to the affidavit.
Mr. Stewart, who couldn't be reached for comment, hasn't been charged. Federal officials said the case is still under investigation and declined to comment.
Agriculture officials say they're bracing for a battle with snails that could take years and cost millions of dollars. Though eradication teams have been clearing the Gutierrezes' property almost daily, they find new snails constantly. "They remove and remove and remove, and it never ends," says Zoila Gutierrez.
Last week, Steven Rigdon, a surveyor with the state agriculture department, scoured Ms. Gutierrez's neighborhood, searching for snails in cool, moist spots where they tend to hang out. He collected dozens of them with his gloved hands and dropped them in Ziploc bags. Once the gastropods are positively identified at the office, they're killed—first frozen and then soaked in antifreeze or alcohol.
Mr. Rigdon says the worst infestation he has encountered so far was at a home in Miami's Little Haiti neighborhood. "We were walking through the yard hearing snails crunch under our feet," he says. "You could sit in one spot, and it was like picking berries."
Florida has had plenty of practice fighting off imported pests, which pop up in the state an average of once a month, says Mr. Gaskalla. Some arrive by chance, carried on cargo ships or air currents, while others are set loose by owners, intentionally or by accident, and then flourish in the subtropical climate.
In recent years, officials have had to contend with Burmese pythons, which prey on native species; Gambian pouched rats, which can grow to the size of a cat and wreak havoc on crops; and pink hibiscus mealybugs, which inject toxic venom into plants. "Florida is the land of opportunity when it comes to invasive exotics," says Mr. Gaskalla.
He says he's optimistic that the eradication campaign will eventually vanquish the snails. "You just have to be persistent," he says, "and stack the odds against them."