A Cure for Euthanasia?
Science 18 Sep 2009:
Vol. 325, Issue 5947, pp. 1490-1493
(continued from page 1491)
Feral dogs, on the other hand, tend to dominate in developing nations. Rowan says India alone is home to up to 35 million “street dogs,” which in 2004 caused the vast majority of the country’s 20,000 human rabies cases. There’s little funding for sterilization programs, he says, so “there’s no way to take these dogs off the streets.” China has also seen a spike in rabies cases and has responded with massive culling campaigns: City workers fan through towns, says Rowan, clubbing dogs to death by the thousands.
“We need to stop the carnage,” says Rowan. “That’s where the whole idea of a better contraceptive comes into play.”
A decade after leaving vet school, Levy began looking into such a contraceptive. She had founded a few high-volume spay/neuter clinics for feral cats—called Operation Catnip—but “the cats were reproducing faster than we could sterilize them,” she says. So Levy asked Kirkpatrick for some of his zona pellucida vaccine. She ran a small clinical trial in cats. But “it had zero efficacy,” she says. Trials in dogs showed similar results. Levy says the antibodies the females produced did not bind to their eggs—and thus did not block sperm entry.
Undaunted, Levy turned to another approach that had proven successful in wildlife: a vaccine called GonaCon. Developed in 1994 by immunologist Lowell Miller at the U.S. Department of Agriculture’s National Wildlife Research Center in Fort Collins, Colorado, the vaccine induces the body to make antibodies against the brain’s gonadotropin-releasing hormone, which signals the production of various sex hormones. In field trials, Miller and colleagues contracepted deer, prairie dogs, and even kangaroos. Levy found that the vaccine also worked well in cats: A single injection contracepted males and females for up to 5 years, although the effect diminished over time. Other groups tried the vaccine in dogs but stopped trials after the injection caused a painful reaction.
In 2004, Levy also began working with a sterilant called ChemSpay. Loretta Mayer, an ovarian physiologist at Northern Arizona University in Flagstaff, had helped develop the product—a chemical that destroys female eggs—and had used it to sterilize feral dogs on a Navajo reservation. Levy saw results in cats, too, but the product required multiple injections over several days, making it impractical for hard-tocatch feral animals.
Levy and Mayer worked to improve the efficacy of GonaCon and ChemSpay, respectively, but both soon ran short of money. “Animal work is horrendously expensive,” says Levy. Each research cat costs her $800—and $5 a day to feed and house. She and Mayer scraped together small grants, but neither could find a large funding agency to support the research. “There were times between grants when I was paying for the cats myself for a year,” says Levy.
Nonsurgical sterilization research stuttered and slowed. An Australian group working on cat contraception abandoned its studies entirely when funding ran out. And then Gary Michelson entered the picture.
A shot in the arm
In November of 2008, postdoc William Ja was taking a break from his lab work at the California Institute of Technology in Pasadena when an ad in a scientific journal caught his eye. Seeking to minimize shelter euthanasia, a Los Angeles–based nonprofit called Found Animals was announcing $75 million toward the development of a nonsurgical sterilant that would work in male and female cats and dogs—$50 million in grants and a $25 million prize for the first team to develop a viable product. “I had never thought about this problem before,” says Ja, “but I was inspired by the challenge.” He brainstormed with some colleagues over dinner and came up with an idea that he thought might work.
The awards are the brainchild of Michelson, a retired spinal surgeon and one of the richest people in the United States, thanks in part to a $1.35 billion settlement over surgical devices he invented. An animal lover who has also donated millions to humanitarian causes, Michelson says he was saddened and frustrated by current animal-control efforts. “The amount that municipalities in the U.S. spend to catch, house, and kill our pet cats and dogs is staggering,” he says. “Surely we should be able to come up with a more cost-effective and humane approach.”
Last year, Michelson’s Found Animals foundation created a review board of scientific advisers and started seeking proposals. The response has been overwhelming. To date, the foundation has received more than 80 pitches—from academics, physicians, and industry scientists, many of whom have no background in companion-animal research. “There’s a lot of very bright people out there who haven’t applied their research direction to dogs and cats, in part because there’s been no money,” says Found Animals scientific director Shirley Johnston, a former veterinarian with a Ph.D. in clinical reproduction. “We’ve seen some very impressive ideas.” (And some that were not so impressive. One proposal described a kitty chastity belt, complete with blueprints.)