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Python parasite spreading among Florida’s native snakes

The invasive snakes brought the parasite to Florida. Now it's spreading without them.

The invasive Burmese pythons plaguing the Everglades brought some baggage with them to Florida.

Lung parasites. Blood sucking ones from southeast Asia that look like tongue-shaped little worms, but are actually a type of crustacean.

New research out of the University of Florida shows the pythons spread those Raillietiella orientalis parasites to Florida’s native snakes, and now the native snakes are spreading it amongst themselves in places where pythons have never slithered.

Larval R. orientalis collected from a shrew.
Larval R. orientalis collected from a shrew. [ PETE DONAHUE | Courtesy of University of Florida ]

“People look at pythons as a Florida problem,” said Melissa Miller, an Invasive Species Research Coordinator with the University of Florida, and lead author of the paper on the parasites published in the latest edition of the journal Ecosphere. “But this is an example of an impact from pythons that can reach far beyond their range.”

Miller said scientists worry the parasites could spread even beyond Florida’s borders, since many of the snake species found within the state are also found outside of it.

The parasites were found in snakes as far north as Lake County, and as close to Tampa Bay as Polk County, both outside the pythons’ range. Though no parasites were found in snakes in the Tampa Bay area, Miller said there’s no reason to think they’re not here.

They were found in 13 species of native snakes, including some of conservation concern, such as the kingsnake and pygmy rattler.

The research was done through road surveys. Miller would drive the state’s back roads collecting road-kill snakes, cruising the same areas on consecutive days to ensure freshness.

In a field truck packed with giant coolers filled with dry ice and dead snakes, she’d make the nine-hour drive back to Auburn University, where Miller was completing post-doctoral work.

“Luckily I was never pulled over and had to explain that,” she said.

Melissa Miller, Invasive Species Research Coordinator with the University of Florida's "Croc Docs" team of wildlife researchers, seen with a kingsnake.
Melissa Miller, Invasive Species Research Coordinator with the University of Florida's "Croc Docs" team of wildlife researchers, seen with a kingsnake. [ PETE DONAHUE ]

A team of undergrads dissected them — 523 native Florida snakes in total.

Miller said the next step in the research is studying how the parasites are affecting the native snakes, but common sense says they aren’t doing anything good.

“I found one snake with 77 of these parasites in its lungs, and the top size was around 80 millimeters, so they’re not small,” Miller said. “If you think of 77 of these in the lung of a snake — our native snakes have one lung — think about trying to avoid a predator. It’s affecting its ability to breathe. It could lead to declines in certain species.”

A threat to snake species could upset the state’s ecological balance. Snakes are predators, but they’re also prey for Florida’s birds, raccoons and fish.

Miller said the parasites seem to grow larger in Florida’s native species, probably because they’re “immunologically naive,” meaning they have no evolutionary history of dealing with them.

The parasites, which feed on blood, spread by laying eggs inside the host’s lungs, which the host eventually poops out. The eggs contaminate water or soil, and are eaten by an intermediate host, like a frog, a shrew, or another small mammal, which is eaten by a snake, starting the cycle anew.

Miller said it’s possible that another reptile invader could be a vector for the parasite. She’s looking at invasive Argentinian tegus, which, it appears, can also transfer the parasite.

Local populations of breeding tegus are known to exist in three Florida counties: Charlotte, Miami-Dade and Hillsborough.