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Fish Skin Bandages Help Burned Bears and Cougar Heal

After receiving grafts of tilapia skin, two bears and a cougar rescued from California's Thomas Fire are doing well.

See How Fish Skin Bandages Help Heal Bears Burned in a California Wildfire

When the Thomas Fire blazed through nearly 282,000 acres of southern California late last year, it left chaos in its wake. The flames claimed 15 peoples' lives and thousands of homes, and they also disrupted the area's wildlife.

After the fire had subsided, vets swooped in to rescue two adult bears—one was pregnant—and a 5-month-old cougar from Los Padres National Forest. The bears had suffered third-degree burns on their paws, and one of them was so injured it couldn't stand. The cougar cub sustained similar second-degree burns.

Along with the California Department of Fish and Wildlife, Jamie Peyton and other UC Davis veterinarians stepped in. Instead of wrapping the animals' paws up in traditional bandages, they turned to a less conventional Band-Aid: tilapia fish skin.

Four Paws

Injured or not, bears and cougars are dangerous animals. For normal operations, they have to be sedated for safety reasons. But the animals can only go under so many times, and sedating them too frequently can risk their health. ("See How Vets Removed a Melon-Size Tongue From a Rescued Bear")

Putting pain pills in their food isn't terribly effective, because there's a chance they might not eat them. Vets can't wrap the injured paws in cloth bandages either, because if the animals chew on their bandages—which they inevitably do—the cloth can block their intestines. (Related: "First Brain Surgery Performed on Bear")

That's where the fish comes in.

The vets knew that fish skin has been used in Brazil to treat human burn victims, so Peyton's Portuguese-speaking colleague called up a doctor there. Due to restrictions, tilapia bandages can't be shipped outside the country, so the U.S. vets had to improvise.

Peyton and her husband visited the local fish market to buy live tilapia. Once they skinned the fish and ate the meat (as to not waste it), they sterilized the skin for several days, modeling the same cold sterilization protocol that's used for skin grafts on people.

Then, they returned to the animals. After anesthetizing the bears and cougar and prepping them for surgery, Peyton and her team of veterinarians cut pieces of tilapia skin to fit over the animals' charred flesh. The amount of fish skin they had to use varied, but generally one bear paw takes about one or two skins.

"It's pretty straightforward," Peyton says.

The wraps are good for about 10 days, but after that they turn leathery. They're still functional, but they don't have the collagen needed to help repair the skin, so the vets have to switch them out.

Watch: Rescued Bear With Amputated Paws Learns to Walk Again

In addition to fish bandages, Peyton and the team used acupuncture, chiropractic treatment, and cold-laser therapy on the animals on days they had to be anesthetized for standard care. These techniques are frequently used on other injured animals, but this was the first time Peyton had used fish skins as bandages for large animals. (Watch: "Treating Animals With Acupuncture")

The treatment seems to be working. The bears, who were released with radio collars on January 17 after one final treatment, are doing well. At that time, about 90 percent of their wounds had healed. (Watch: "Rescued Bear With Amputated Paws Learns to Walk Again")

The cougar cub is also doing well.

"He acts like a kitten now," Peyton says. "He's playing. Just into everything, causing trouble."

Showing Skin

Like human skin, tilapia skin contains certain collagen proteins that are essential for scarring. The fish skin is also resistant—it can withstand more tension than human skin and holds up against moisture. Before use, bandages made in Brazil are sterilized with radiation and, once they've been packaged and refrigerated, can last up to two years.

Tilapia bandages, which can be changed a few times over several weeks, are left on until natural scarring takes over. In humans, the fish bandages cut down on healing time and the need for pain medications.

In the U.S., tens of thousands of donors provide tissue for transplant. About 1.5 million tissue transplants are performed annually to help burn victims, injured athletes, and military members recover. With this number of donations, outfitting humans with tilapia skin bandages is unlikely in the near future, experts say. (Watch: "Brain Surgery Live With Mental Floss")

But it's a good innovation for wildlife, Peyton says. She's hoping that this sort of treatment could change how burned animals are helped in the future.

"I think the wildlife definitely presents us with different challenges," Peyton says. "Now, these few animals change the way we may treat burns in the future for other animals."