Since then more than 400 dead turtles have shown up. Dozens more sick turtles were also recovered, each of which was lethargic, emaciated and covered in infected lesions in their eyes, skin and even internal organs.

None of the infected turtles survived.

The 60-kilometer river is the only home to the Bellinger River snapping turtle (Elsaya georgesi), a rare but little-studied species that has already been on the decline for years due to pollution and predation by invasive foxes. Scientists now fear that this mysterious, as-yet-unidentified disease has reached 90 percent of the turtle’s habitat and could cause the species’s imminent extinction.