GAINESVILLE, Fla. – A potentially deadly parasite that can cause meningitis in humans and animals has been found in five Florida counties, including St. Johns and Alachua, according to University of Florida researchers.
A study in PLoS ONE, which was conducted by researchers in the UF College of Veterinary Medicine and the Florida Museum of Natural History, found that rats and snails in St. Johns, Alachua, Leon, Orange and Hillsborough counties tested positive for the parasite called rat lungworm.
Rat lungworm, which originated in Hawaii and is occasionally found in the southern U.S., relies on rat and snail hosts to complete its life cycle but can pose a health risk to humans and animals that ingest infected snails.
While the fatality rate of infection in humans is low, the parasite can cause eosinophilic meningitis if it becomes trapped and dies in the brain, and severe infections can cause coma or death.
Symptoms of infection in adults include headache, stiff neck, fever, vomiting, nausea and paralysis of the face and limbs. The most common signs of infection in children are nausea, vomiting and fever.
This study sheds new light on the extent of the parasite’s geographic range in Florida, said Heather Stockdale Walden, an assistant professor in the UF department of infectious diseases and pathology and the study’s lead author.
“The parasite is here in Florida and is something that needs to be taken seriously,” she said. “The reality is that it is probably in more counties than we found it in, and it is also probably more prevalent in the southeastern U.S. than we think."
While snails live most of their lives within a small area, they can easily be transported on cargo containers and in potted plants, which is probably how the parasite first arrived in Florida, said study co-author John Slapcinsky, collections manager of invertebrate zoology at the Florida Museum.
Humans can ingest the parasite by consuming infected snails or infected frogs and crustaceans.
Stockdale Walden said more than 2,800 cases of human rat lungworm infection have been documented worldwide since the parasite was described, but the actual number of cases is likely greater as the disease can go undetected or be misdiagnosed.
While no human cases of infection with rat lungworm have been reported in Florida, eating lungworm-infected snails killed a white-handed gibbon at Zoo Miami in 2003 and a privately owned orangutan in Miami in 2012.
Several steps can help lower the risk of infection, Stockdale Walden said.
“Wash produce,” she said. “Some snails are very small and can easily hide in lettuce leaves. Teach children not to eat snails, and if they handle snails, make sure they wash their hands. Be aware of the potential risks associated with eating snails and also raw or undercooked frogs and crustaceans.”
Nutritionist Melissa Collins agreed with that advice, saying people need to wash every fruit and vegetable before eating them.
"Vinegar and water is what I use to clean my vegetables," Collins told News4Jax on Wednesday. "And just making sure you are storing them properly and when you are going to the grocery store, you are picking stuff that looks ripe and not rotten."
Infection with rat lungworm can also cause meningitis in animals, as well as limb weakness or paralysis, neck pain and central nervous system problems.
To protect pets and livestock, be mindful of snails in animals’ living space, Stockdale Walden said. Check watering troughs for snails that might have fallen in and monitor animals for snail-eating habits.
“If you have questions about your pet, contact your veterinarian and discuss your concerns,” she said.
Pet owners are urged to be on the look out since the parasite can be found in rats and snails often found in yards.
"I don't let him smell any other dog. And I walk out and make sure he doesn't eat any mushrooms or anything like frogs or anything that has been run over," said dog owner, Petee Uinta.
Added dog owner, Brent Blythe, "I go on a walk, it takes me like two hours because he tries to eat everything he sees, so I'm on constant alert."
Funding from the National Center for Veterinary Parasitology and from the University of Florida supported the research.