Native snakes susceptible to northern spread of invasive lung parasites

Aug 14, 2023

As invasive Burmese pythons make their way through Florida’s ecosystems, they carry a weapon that threatens our native snake species across North America.  

In these pythons’ lungs are pentastomes (Raillietiella orientalis) which are small parasitic crustaceans that, once mature, reside in the respiratory systems of snakes, feed on the blood of their hosts, and infect them with pentastomiasis, an infection with largely unknown effects.  

While Raillietiella orientalis is an invasive species, we do have pentastomes native to North America that infect snakes, but the invasive R. orientalis is of concern because of the impacts both known and unknown to native snake species. We are unaware of how far their range in the U.S. can expand, the extent of damage caused to their intermediate and final hosts, the long-term population effects and how to control their spread.

These parasites were first introduced to Florida by non-native Burmese pythons through the pet trade.

Pentastomes have been found further north throughout Florida since 2017. There is concern that the invasive species could deeply impact the health of native snakes. Map courtesy of Partners in Amphibian and Reptile Conservation

Due to the large size of the pythons the pentastomes can reside in the lungs and rarely kill their host. Unfortunately, yet to be understood is the impacts on our smaller native snakes once they are unleashed into our ecosystem.  

The pentastome life cycle is typical of many parasitic organisms. Pentastome eggs are released through the snake’s gastrointestinal system when the snake exudes fecal matter. The fecal matter as well as the eggs are then eaten by an insect.  

The insect is then eaten by an intermediate host which several studies suggest include amphibians and reptiles. Our native Florida snakes then eat these intermediate hosts becoming the host for the pentastome to mature.  

The spillover of pentastomes to our native snakes wreaks havoc on their respiratory systems.  

Their lungs, much smaller than Burmese pythons, cannot function with pentastomes. Lung inflammation, infections and decreased ability to breathe all lead to adverse side effects in our snakes, causing morbidity and mortality.  

We can start to imagine the threat of R. orientalis when we look at the recent decline in Pygmy rattlesnakes in the Everglades which could be due in part by the spread of R. orientalis.  

This issue does not stop with pythons. Pentastomes, with the aid of intermediate hosts and the pet trade, have been able to spread as far north as Michigan, a much wider range than the Burmese pythons that inhabit South Florida. Unknowingly infected intermediate hosts are shipped across the country and are released into countless ecosystems.  

As this issue develops, in Spring 2024 Tall Timbers will launch a snake ecology study and will be evaluating the disease status of snakes on Tall Timbers and stay engaged with Partners in Amphibian and Reptile Conservation’s research. PARC has also set up an email system to report sightings of potentially diseased amphibians and reptiles.

Pentastomes commonly flee their dead hosts, leaving the lungs of snakes from their mouths. A snake that appears to have white worms protruding from its mouth could be infested with invasive pentastomes.

If you are in the Red Hills and Albany regions of Southwest Georgia and North Florida and suspect you’ve encountered an infected snake, you can contact Kim Sash, Tall Timbers’ Biological Monitoring Coordinator, directly at or by phone at (850) 893-4153 ext. 336.

Photos were collected as part of the following study: Documenting Range Expansion of the Invasive Pentastome Parasite, Raillietiella orientalis, Using Southern Black Racer and Eastern Coachwhip Road Mortality 


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