UF research into new birth-control vaccine for cats shows promise

Julie Levy believes an ounce of prevention is worth a pound of cure – particularly when prevention is humane, cost-effective and efficient, and could save the lives of stray and feral cats around the world.

For female cats, the ounce of prevention may just come in the form of a one-shot birth control vaccine. Levy, an assistant professor of small animal medicine at the University of Florida College of Veterinary Medicine, and graduate student Shawn Gorman are investigating a new type of vaccine that would provide an inexpensive, easy-to-administer means of sterilization compared with traditional spay programs. As such it could be used in tandem with such programs where they exist, or perhaps in place of them where they do not.

So far, Levy’s research shows that immunocontraception – a means of triggering the immune system into preventing egg fertilization - is promising.

“We’ve seen good antibody responses to the vaccine, which means the cats’ immune systems respond to it,” Levy said. “That’s the first hurdle we had to overcome. The next step will be to see if those antibodies can prevent pregnancy in breeding trials.”

Those studies are underway now, she added.

“Whether or not these trials prove to be as successful as we hope, we will know much more about how to prevent pregnancy in cats without surgery and continue to refine the vaccines until we have something that is reliable and safe for cats,” Levy said.

Levy is co-founder of Operation Catnip, an organization that provides free surgical spay-neuter services to the stray and feral cat population of Alachua County through monthly clinics run by volunteers.

“There are more than 60 million pet cats in the United States, and there are about 60 million stray cats without a home,” Levy said. “The only humane way to control their population is through sterilization.”

More than 4000 cats have received free spay or neutering procedures through Operation Catnip since the program’s inception in 1998. A recent study conducted by Levy and students showed that about 12 percent of Alachua County’s households feed stray cats. While more than 80 percent of the pet population has been spayed, most stray and feral cats have not been.

“We just can’t keep up with the need,” Levy said. “Spaying is very expensive and very cumbersome. For much of the world, no veterinary care is available whatsoever and animal control, if it takes place at all, is through poisoning dogs and cats.”

With funding from the Morris Animal Foundation and the Winn Feline Foundation, Levy and her colleagues are testing the experimental birth control vaccine known as SpayVac, the result of 10 years of research initially directed at contraception in seals.

“We’re collaborating with Dr. Robert Brown at Dalhousie University, Nova Scotia, who invented the vaccine,” Levy said. “Dr. Brown and his colleagues found that a single injection of SpayVac prevented pregnancy in seals for at least six years. Since then, it has also been shown to be effective in rabbits, Barbary sheep and deer.”

The reason the UF team picked this product to test first is that it looks like it might work with a single dose.

“This is especially important with stray cats, because you can trap them, vaccinate them and then turn them loose,” Levy said. “The opportunity to capture the cats a second time for additional vaccines is severely limited, so if it works, it would be very exciting.”

All cats involved in the study eventually will be offered for adoption into permanent homes. Currently, a dozen mother cats and their kittens are ready for adoption. They have all received their routine shots, been spayed or neutered, and are free of feline leukemia virus and feline immunodeficiency virus. Pictures of the cats can be seen on the World Wide Web at www.petfinder.org in the “feline friends” category. Anyone interested in adopting a kitten or cat should contact Levy at (352) 392-4700, Ext. 5731.