Due to the ongoing rainy season, Southwest Florida is seeing a growing number of New Guinea Flatworms, a nonnative species that poses both ecological and health risks, according to the Florida Fish & Wildlife Commission (FWC). These flatworms, which range from about 1.5 to 5 inches in length, are dark brown or black with a pale stripe running down the middle of their bodies. New Guinea Flatworms are typically found in dark, moist environments such as potted plants, under rocks, and in dense vegetation, including gardens.
"In an area of a 12 by 12, I could find 50 of these worms," said Jeanine Tilford, the founder of the East Coast-based invasive removal company ToadBusters.
Since 2016, New Guinea Flatworms have been tracked as part of the University of Georgia's invasive species monitoring system, EDDMaps.
- Charlotte County (83 sightings)
- Collier County (98 sightings)
- Lee County (398 sightings)
"The population is so much larger than that. Most people wouldn't know to call FWC and report a worm," said Tilford.
The flatworms are toxic in two ways, both internally, and externally. In order to capture and subdue prey, mostly earthworms, the New Guinea Flatworms secrete a Tetrodotoxin.
"It's the same toxin found in blowfish, which paralyzes their prey. That can be found on the worm's skin, and can cause pretty severe irritation," added Tilford, who is currently working on a non-toxic, chemical treatment for the invasive pests.
Internally, New Guinea Flatworms are one of the known carriers of the Rat Lungworm Parasite, according to the University of Florida's Institute of Food and Agricultural Sciences. Rat lungworm, if ingested, can cause eosinophilic meningitis, which has symptoms ranging from moderate fever and vomiting to paralysis and death in severe cases, according to UF/IFAS.
"When parasites end up in an aberrant host or any host that they don't belong in, they tend to move upwards. When they move up, they get up to your brain. That's the danger zone," said Christina Anaya, a biology professor and parasitic researcher at Florida Gulf Coast University (FGCU).
"When the parasite goes through you, it gets into your body, into your spinal column and goes to your brain and dies, which results in meningitis. Most of the time that's fatal, and by that time there's not much that can be done. So it's a scary, scary parasite," added Tilford.
Exposure topically to the worm's tetrodotoxin can cause skin irritation and rashes, while ingestion is required to be exposed to Rat Lungworm, according to FGCU researchers. In order to prevent illness, it is recommended to wash all produce, and keep small children and pets away from areas where worms are present.
"There's no way to eradicate them. They're just too quick to repopulate and come back, but we can manage the population in the areas we don't want them," said Tilford.
If you see large groups of New Guinea Flatworms, contact the Florida Fish & Wildlife Commission.