“Sharks are remarkably resistant to viruses,” study researcher Michael Zasloff, of the Georgetown University Medical Center, told LiveScience. Zasloff discovered the molecule, squalamine, in 1993 in the dogfish shark, a small- to medium-size shark found in the Atlantic, Pacific, and Indian Oceans.

“It looked like no other compound that had been described in any animal or plant before. It was something completely unique,” Zasloff said. The compound is a potent antibacterial and has shown efficacy in treating human cancers and an eye condition known as macular degeneration, which causes blindness.
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By studying the compound’s structure and how it works in the human body, Zasloff thought it might have some antiviral properties. He saw that the molecule works by sticking to the cell membranes of the liver and blood vessels. While there, it kicks off other proteins, some of which are essential for viruses to enter and survive in the cell.

The researchers decided to test the compound on several different live viruses that infect liver cells, including hepatitis B, dengue virus and yellow fever. They saw high efficacy across the board.
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Zasloff hopes to start human trials in the next few years.
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Marc Maresca, a researcher at Paul Cézanne University in Aix-en-Provence, France, who wasn’t involved in the study, agreed that the concentrations used were quite high, possibly in toxic ranges for some cells, but in an email to LiveScience Meresca also called the study “very exciting.”