Burmese python. Image by skeeze from Pixabay
A lung parasite is negatively affecting the Burmese python population of Florida as well as Florida’s native snakes and animals. New research out of the University of Florida shows the pythons spread a parasite also known as Raillietiella orientalis to Florida’s native snakes, and now the native snakes are spreading it amongst themselves.
The Burmese python is the third largest snake in the world and it is a consummate hunter. It is equally at home swimming through water as it is at climbing trees, and it eats whatever that it can wrap around and swallow. While it is native to Southeast Asia, it has also been introduced to Florida and their presence has caused all kinds of ecological disruptions. Being such a large predator with a broad appetite, many native animals (including alligators) of the Everglades are at risk of becoming python food.
The parasite itself is a blood-sucking, tongue shaped little worm from southeast Asia. It is actually a type of crustacean. These parasites are called “tongue worms” not because they live on the tongue, nor because they are “worms” necessarily. They are called so from the appearance of the adult pentastomida which are shaped somewhat like a long tongue, and instead of being “worms”, they are in fact a lineage of crustaceans that have evolved to live as respiratory tract parasites in terrestrial vertebrates, mostly reptiles.
The parasites spread by laying eggs inside the host’s lungs, which the host eventually defecates 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, continuing the harmful cycle on and on and on.
The parasite can block respiratory passages, reduce snake reproduction rates and adversely affect its metabolism. And much like the coronavirus, it travels. Fast.The parasite is advancing north as native snakes spread it to each other. Melissa Miller, coordinator for invasive species research for the University of Florida’s Croc Docs in Fort Lauderdale and lead author of the paper on the parasites published in the latest edition of the journal Ecosphere, said the northern boundary of the parasite appears to be around Gainesville, but that it could eventually threaten species outside of Florida.
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, driving by the same areas on consecutive days to ensure freshness. A team of undergrads dissected a total of 523 native Florida snakes.
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. The Argentine Tegu is another invasive species that is potentially spreading the parasite. You may read more about them in our “Giant” Lizard Established as an Invasive Species in Florida post.
Porocephalus crotali is a parasite which infects the snakes of North and South America and is a Florida native. It was previously thought that P. crotali can only infect vipers, but now it adds the Burmese python to its list of hosts. The presence of this parasite in those Burmese pythons shows that it wasn’t as picky as previously thought. The reason why P. crotali was previously only found in vipers wasn’t because they were particularly picky, but the opportunity for it to infect other types of snakes never came up (until the Burmese python was introduced.)
The danger of this getting out of hand is the risk of more parasites to native Florida snakes. Not only did the Burmese python add another species of parasite that can infect them, but they would also be dealing with higher prevalence of the native parasite because the Burmese python is acting as an additional breeding ground for P. crotali.
As you can see, foreign and native snakes coming in contact means they also end up exchanging parasites with one another. Despite this affecting many ecosystems around the world, the ecological impact of these parasite exchanges for most habitats is still largely unknown.