Warning of ‘Mouth On Its Belly’ Worm Infestation in Florida

October 4, 2018 Updated: October 4, 2018

The New Guinea flatworm, a creature on the world’s most invasive species list, is causing concern among some central Florida residents amidst new reports of sightings of the species that could carry the dangerous rat lungworm parasite.

WESH 2 News reported that it had received photos of a suspected New Guinea flatworm found in Grant, Brevard County, inside a residential home. The news service also noted a total of 17 reports of flatworms in Indian River County, located several miles from Grant.

The University of Florida Institute of Food and Agriculture issued a warning, in which it calls the flatworm one of the “World’s Worst Invasive Alien Species.”

Nuw Guinea flatworm in Japan
Undated photo of the New Guinea flatworm (platydemus manokwari) taken at the Ogasawara Islands, Japan. The creature’s head is on the right. (Shinji Sugiura [CC BY 4.0 (https://creativecommons.org/licenses/by/4.0)], via Wikimedia Commons)
“DO NOT TOUCH it with your bare hands, the worms produce toxic chemicals and might induce allergic reactions,” the warning cautions. “It also known to carry rat lungworm, a parasite that can cause a form of meningitis in humans and animals.”

“It’s a flatworm, which kind of looks like a cross between a slug and a small earthworm,” wrote Mary Ann Pigora, an affiliate of the Institute of Food and Agriculture Sciences at the University of Florida (UFIFAS) in a blog.

“It can be identified by its pointy ends and a thin tan stripe down its back. Under a microscope, it has eyes—creepy!—and a mouth on its belly.”

A partial bottom view of the flatworm
A March 26, 2014 photo of the New Guinea flatworm. (Pierre Gros [CC BY 4.0 (https://creativecommons.org/licenses/by/4.0)], via Wikimedia Commons)
Pigora, a UFIFAS Extension Orange County Master Gardener, called the New Guinea flatworm a “serious pest to our native snails and slugs. Birds don’t like them—they taste nasty.”

But flatworms are more than just a danger to habitat.

“Humans normally wouldn’t care much about these worms,” Pigora wrote. “They don’t hurt us… directly. Unfortunately, they can be a host to a microscopic parasite that does cause disease.”

New Guinea flatworms can carry a parasite called rat lungworm.

Angiostrongylus cantonensis is a parasitic worm of rats. It is also called the rat lungworm. The adult form of the parasite is found only in rodents. Infected rats pass larvae of the parasite in their feces. Snails and slugs get infected by ingesting the larvae. These larvae mature in snails and slugs but do not become adult worms. The life cycle is completed when rats eat infected snails or slugs and the larvae further mature to become adult worms,” according to the CDC.

“People can get infected by eating raw or undercooked snails or slugs that are infected with this parasite. In some cultures, snails are commonly eaten,” the CDC stated.

Flatworm preying on a snail
The flatworm preying on a snail in an unspecified location in France. (Pierre Gros / CC BY 4.0 via Wikimedia Commons)

“Some infected people don’t have any symptoms—or have only mild symptoms that don’t last very long. Sometimes the infection causes a rare type of meningitis (eosinophilic meningitis). The symptoms can include headache, stiff neck, tingling or painful feelings in the skin, low-grade fever, nausea, and vomiting,” according to the CDC.

Jamie Vasquez, a branch manager with Tropical Pest Control in West Palm Beach, said humans could come into contact with rat lungworm through contaminated air particles.

“The rats will defecate and snails will eat the feces. And then the flatworm will eat the snails. It’s a cycle that repeats within themselves,” he said, according to WPTV. “If a rodent infestation occurs in your house, and they chew through the A/C vents in your house, they can defecate in the vents and that can transmit to human also through air particles.”

The worms can also crawl on fruits and vegetables and contaminate them.

“If you don’t wash them, you can contract meningitis that way,” Vasquez said.

The Florida Fish & Wildlife Conservation Commission (FWC) has in the past urged caution when encountering New Guinea flatworms, WINK reported.

Melody Kilborn, a spokesperson for FWC, told the Naples Herald that the easiest way to deal with the pest is by dousing the soil they’ve been spotted in with hot water.

The Herald cited FWC officials as advising people to inspect all new plants or gardening materials before moving them to a new area to prevent uncontrolled spread of the flatworm.

Research done in France suggests flatworms pose a significant threat to some ecosystems.

“Examined from an environmental perspective, P. manokwari has demonstrably had a serious negative impact on the biodiversity of native snail populations in the Pacific region […] and wherever it is deliberately or accidentally introduced it will continue to pose a threat not only to native molluscs, but possibly to other slow-moving soil invertebrates […] It may also indirectly have a negative impact on vertebrate species dependent upon these soil invertebrates,” according the study The invasive New Guinea flatworm Platydemus manokwari in France, the first record for Europe: time for action is now.

Florida International University professor of biology Timothy Collins, who studies flatworms in Florida, told Snopes.com that there have not been any reported cases in the state of flatworms carrying the rat lungworm parasite.

“The average person can avoid risk by not handling the flatworms, or if they do, by not putting their hands near their eyes or nose before cleaning them carefully. In addition to the health risk, Platydemus have been reported by some brave soul to taste terrible, so eating them is a bad idea all around.”

Data from the Early Detection and Distribution Mapping System (EDDMapS), a University of Georgia reporting and mapping system for invasive species, shows reports of the flatworm all throughout the Florida Peninsula.

flatworm sightings
New Guinea flatworm sightings in Florida, according to EDDMapS, an invasive species monitoring system set up by Center for Invasive Species and Ecosystem Health at the University of Georgia. (Screenshot via EDDMapS)

“The FWC is aware that New Guinea flatworms have spread to many parts of Florida, and people do not need to report sightings,” the FWC told Snope.com in an email.

“It might take years for the right factors to fall into place to allow a species to expand its range and cause ecological problems,” the FWC said on its website. “For example, green iguanas have resided in Florida since the 1960’s, but their population has increased greatly since Hurricane Andrew.”

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