Parasite colonising Florida snails could pose health risk

University of Florida researchers have confirmed the presence of a deadly parasite in three non-native species of snails that have colonized South Florida. The parasite, rat lungworm (Angiostrongylus cantonensis), is a tiny worm that can sicken humans and animals including horses, dogs and birds.
The study that confirmed the parasite's presence in three of five tested snail species, was prompted by the death of an orangutan who was treated at the University of Florida. The ape became sick after consuming snails infected snails.
The discovery, detailed this week in a study published in the Journal of Parasitology, is rare for the continental United States. The parasite is only known to be established in Hawaii.
"Determining the geographic distribution of this parasite in Florida is important due to the hazards to human health," lead study author Heather Walden, an assistant professor of parasitology at Florida's College of Veterinary Medicine, explained in a press release.
The parasite was found in invasive snails that tend to hang out and feed on exotic plants. Florida's large horticulture industry heightens the risk of infected snails making their way to new gardens and new parts of the state.
"Most of the snails found to be intermediate hosts for this parasite in our study are invasive and some feed on or shelter on ornamental plants, which have the potential for distribution throughout Florida and in other areas of the United States," Walden added.
The parasitic nematode -- which uses rats as its main host and gastropods like snails as intermediate hosts -- can invade the brain tissue of humans and animals, causing a meningitis-like infection that can sometimes prove fatal.
But humans are only incidental hosts, and infection is easily avoided with the proper precautions.
"Humans can't become infected with this parasite unless they eat an undercooked or raw snail," Walden said. "Some animal species can harbor the infective larvae, like different crustaceans or frogs. As long as food is cooked and you wash your produce, you will most likely never ingest it."
While every region of the United States has invasive species problems, Florida is especially populated with non-natives species. The state's warm climate and position as a transportation hub are to blame.
One study found that over the last 50 years, 130 non-native species of amphibians and reptiles have been introduced into the Sunshine State -- including Burmese pythons, Cuban tree frogs and Argentine tegus.
Not only is the situation dangerous to human health and ecologically destructive, some estimates suggest Florida spends as much as $500 million a year mitigating the damage caused by invasive species.