How the Key Deer Survived a Flesh-Eating Parasite: The 2016 Screwworm Outbreak

By Chester Moore

When the New World screwworm returned to the Florida Keys in 2016, it threatened one of America’s most beloved and vulnerable wildlife populations. The endangered Key deer, found nowhere else on Earth, suddenly faced an invisible predator unlike any hurricane, habitat loss, or vehicle collision. This predator wasn’t a mammal or a bird—it was a flesh-eating parasite capable of inflicting devastating wounds on living animals.

The outbreak became one of the most significant wildlife health emergencies in recent U.S. conservation history. Wildlife biologists, veterinarians, entomologists, and state and federal agencies mobilized to stop the parasite before it spread beyond the Florida Keys. In this episode of Dark Outdoors, Chester Moore examines the remarkable story of the Key deer screwworm outbreak, the lessons it offers today as screwworm returns to Texas, and how science and conservation came together to save an endangered species from an extraordinary threat.

Dark Outdoors Podcast | Episode 70

Listen to the episode:

Apple Podcasts: https://podcasts.apple.com/us/podcast/the-key-deer-the-screwworm/id1630809603?i=1000774806779

Spotify: https://open.spotify.com/episode/4Y4mQLW7xVHaYZeFVc2IoY?si=VlPyceWQRsywq27k6Yk8TQ

Investigation Summary

Episode 70 revisits the 2016 New World screwworm outbreak that struck the endangered Key deer in the Florida Keys. The parasite, whose larvae consume living tissue, spread rapidly through the isolated deer population, creating one of the greatest wildlife disease challenges the species had ever faced.

Approximately 15 percent of the Key deer population was lost before wildlife agencies gained control of the outbreak. Despite those losses, the coordinated response demonstrated how quickly conservation professionals could mobilize when an endangered species faced an immediate biological threat.

The episode examines the extensive efforts undertaken by wildlife agencies, including surveillance, treatment of infected animals, public education, and the release of sterile screwworm flies to halt reproduction. That strategy ultimately eliminated the outbreak and prevented further spread to mainland wildlife populations.

What You’ll Hear

You’ll hear the story of the endangered Key deer and why this small subspecies represents one of America’s most remarkable wildlife conservation success stories.

The episode explains how the New World screwworm invaded the Florida Keys, why the parasite spread so quickly among deer, and how wildlife professionals recognized the outbreak before launching one of the most intensive wildlife health responses in recent memory.

Chester Moore also explores the many lessons that emerged from the Key deer crisis. The coordinated effort between federal agencies, state wildlife officials, veterinarians, entomologists, and local communities demonstrated that even a severe outbreak can be contained when science, surveillance, and rapid action work together.

As the New World screwworm once again threatens wildlife and livestock in Texas, the Key deer story offers an important reminder that history provides valuable guidance. The successful response in Florida demonstrates that while the parasite presents a serious conservation challenge, effective management strategies already exist and continue to inform today’s response efforts.

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About Chester Moore

Chester Moore is an award-winning wildlife journalist, investigative outdoor writer, and host of Dark Outdoors. For more than three decades, he has reported on endangered species, wildlife conservation, emerging threats to native wildlife, and the people working to protect North America’s natural heritage. Through Dark Outdoors, he combines investigative journalism with a passion for conservation to tell the stories that matter most for wildlife and the outdoors.