Finally, an encouraging report from the front lines of Florida’s largely losing battle against invasive species.
The giant African land snail, a mollusk that grows as a big as a rat and boasts a voracious appetite for stucco and just about any green leafy thing, has been contained. It remains a long way from being wiped out but its numbers are in sharp decline and it has not spread beyond the boundaries of Miami-Dade County.
“We are making great strides in the eradication of this pest,” said Florida Agriculture Commissioner Adam Putnam on Thursday at Douglas Park in Miami, only a few blocks from where the first snail was identified two years ago.
Putnam and other state and federal agricultural officials credited an intensive attack against the fast-breeding and destructive exotic for turning the tide.
“The population is starting to nose dive,” said Richard Gaskalla, director of the division of plant industry for the Florida Department of Agriculture and Consumer Services. Over the last two years, a full-time crew of 50 workers has collected 128,000 snails from 576 properties in 21 hot spots across the county, ranging from Homestead in the south to Carol City in the north. The program has been expensive. At $7.8 million to date — with $1.4 million coming from the state and $6.5 million from the U.S. Department of Agriculture — it breaks down to about $61 per captured snail.
But Putnam said the effort was worth it to control an invader he called a “triple threat” because it poses potentially serious dangers to the natural environment, the state’s $100 billion agricultural industry and human health.
The snail, in some places where it is found in the wild, can carry a parasite called the rat lungworm that can cause meningitis, with the infection passed on to humans either by consuming raw snail or slime-smeared unwashed produce or by rubbing the mucus in your eyes, nose or mouth. No cases in Miami-Dade have been traced to snails but state scientists have found the parasites in some captured snails.
“We see a lot of strange things in this state of Florida but this is at the top of the list,” said Putnam.
For starters, the snails are hermaphrodites, equipped with both male and female apparatus. Once they mate, both can lay eggs, up to 1,200 annually. They can live for up to nine years, and reach eight inches in length.
But it takes several years for them to grow large enough for anyone but an expert or trained snail hunter to tell them apart from assorted non-threatening native snails. That’s one explanation for how such sluggish creatures have managed to spread.
“They’re slow but they’re persistent,” said Gaskalla. “They could make their way across this park in a day or two.”
They also may have been moved across the county in potted plants and yard cuttings or by people who have illegally imported them or kept them to use for a variety of purposes, from a natural cosmetic skin treatment to unusual religious rituals.
How the snail got to South Florida isn’t clear.
In 2010, federal authorities raided the Hialeah home of a practitioner of a traditional African religion called Ifa Orisha who had allegedly smuggled snails to use as part of a healing ritual that involved his followers drinking snail mucus. The investigation began after complaints that some followers had gotten sick, though not with meningitis.
Putnam and other agricultural officials would not discuss a case they said remained under investigation but stressed that the snails may have wound up in Miami in a number of different ways.
It’s not the first time the state has battled the snails.
A Miami boy smuggled three of them home from a 1966 trip to Hawaii, where they have long been established. His grandmother wasn’t as keen about keeping them as pets and set them free in her garden. It took 10 years to eradicate the resulting explosion, with 17,000 of the snails eventually destroyed at a cost of $1 million at the time.
This time, the infestation is more severe. Agricultural officials credited a public outreach program for helping field crews track the pests, with calls from residents to a hotline accounting for 85 percent of new finds. The number: 1-888-397-1517.
In the last few weeks, they’ve also begin experimenting with a snail-sniffing dog — a three-year-old Labrador named Bear, trained at the USDA National Detector Dog Training Center in Georgia. Trainer Jodi Daughtery said the dog shows promise in digging out hard-to-find snails.
But a potent new pesticide that went into use in April has provided the biggest boost, said Gaskalla, with the percentage of snails found dead rising from 40 to 50 percent to 80 to 90 percent.
The state obtained approval from the U.S. Environmental Protection Agency in the spring to use the product, Ortho Bug-Geta. The granules contain an ingredient called methaldehyde, known to be toxic to dogs or other animals that might feed on it. But Gaskalla said the snail bait, sold over the counter at gardening stores, is safe if used properly.
“It’s been a game changer for us,’’ he said.