Two University of Louisville researchers acclaimed for helping invent the world's first cervical cancer vaccine are now being honored for research that could help save endangered manatees.
Scientists working to rehabilitate injured manatees started to see that a close cousin of the human papillomavirus, which causes most cervical cancer in women, was infecting the 1,000-pound sea mammals in captivity.
Worried the sick animals could infect others in the wild, they enlisted the help of Dr. A. Bennett Jenson and colleague Shin-je Ghim, world-renowned papillomavirus researchers.
"I had never seen a manatee before. Once I did, it was love at first sight," said Jenson, who with Ghim earned the Manatee Conservation Award from the U.S. Fish and Wildlife Service in December. "They're huge, but they are so gentle."
According to the Journal of the American Veterinary Medical Association, Florida veterinarian Gregory Bossart identified a manatee-specific papillomavirus in 1997 after seven manatees at a wildlife park developed wart-like growths on their skin.
The Louisville researchers got involved shortly afterward and worked with wildlife biologists to isolate the virus and develop a test for it.
Researchers concluded that manatee papillomavirus was an ancient germ that usually lay dormant in healthy, wild animals. But in stressed, sick or injured manatees rescued by humans, the virus caused open lesions.
"This told us that the immune system had to be weakened" for the disease to occur, Jenson said. "I think that was the key. The ones who are robustly healthy and develop the virus can clear it."
Scientists speculated that manatee infections were often caused by stress from temperature changes in water. Manatees, which generally live close to the coastline, also become sick, injured or stressed because of collisions with boats and destruction of their food supply -- sea grass -- because of pollution and coastal development.
Jenson said many infected manatees developed large lesions and spread the virus by rubbing, nuzzling or other casual contact. In one area, seven of nine manatees being rehabilitated developed infections.
This presented a problem, because scientists generally try to return rehabilitated animals to the wild. "The big concern is you were introducing an infection to manatees who are robust and healthy," Jenson said.
Katie Tripp, director of science and conservation at the Florida-based Save the Manatee Club, said the infections are a warning sign about the overall health of the dwindling populations of manatees. She said only about 3,300 Florida manatees are left.
"They are vulnerable," Tripp said.
Jenson said now that he's grown to love the animals, he is more committed than ever to helping save them. He and Ghim are in the process of developing a preventive vaccine for manatees -- something Tripp said would be very helpful.
"I worry we'll lose the manatees," Jenson said. "They're just really, really gentle creatures that don't deserve extinction."