Balancing the risk

Your terrier has wanderlust.

But he's also got an electronic identification chip implanted under his skin, so you can relax.

Or can you?

Suddenly, "microchipping" of pets has acquired something of a bad name.

Competing chip makers, each claiming their product is superior. Scanners incapable of detecting all chips, causing beloved animals to linger in shelters or be sent to death row. And, perhaps most alarming of all, a reported link between microchips and cancer in dogs and laboratory rats.

Pet owners who have long believed microchips to be the best insurance against losing their animals are understandably confused.

To chip or not to chip?

Most mainstream veterinarians say microchipping pets still makes sense.

They argue that the cancer claims are overblown and that flaws in the chipping system are outweighed by the potential benefits that the technology offers.

"Getting lost is one of the greatest dangers that a pet can possibly face," says veterinarian Marty Becker, who with business partner Gina Spadafori writes a syndicated column that appears in The Bee. Too often, it means death on the streets or in shelters.

According to the Humane Society of the United States, more than 6 million dogs and cats enter animal shelters each year. Only about 30 percent of dogs and fewer than 5 percent of cats are reclaimed by their owners. Because shelters have limited space, unclaimed animals can be put to death within days of their arrival.

"It's an enormous cost to society when animals come into shelters and they have families that love them but we can't find them," says veterinarian Kate Hurley, director of the Koret Shelter Medicine Program at the UC Davis Center for Companion Animal Health. "The risk of animals getting lost is so real, and it directly and rampantly leads to their deaths."

Good value but not foolproof

Microchips, computer chips about the size of a grain of rice and injected under the skin, go a long way toward preventing those heartbreaking scenarios, say Hurley and others. The chips contain identification information that, when detected by special scanners, shelter workers can use to find owners of wayward pets.

Millions of dogs and cats in the United States carry the chips, and manufacturers of the technology use Web sites and marketing campaigns to tell heartwarming stories of reunions. One of a handful of major players, HomeAgain Pet Recovery Service, estimates that 400,000 animals have been returned to their owners thanks to the company's microchip IDs.

"Even if your animal is wearing a collar and an ID, things happen," Hurley says. "Collars come off. Tags fall off. Maybe the animal runs away from the groomer. The microchip is permanent. If there's a natural disaster and your animal is missing but has a microchip, a shelter can find you even if you're 3,500 miles away."

Costs of microchipping an animal range from nominal fees shelters include in the costs of adopting a pet to around $100 at some veterinary offices.

"It's a cheap investment compared to so many of the things we do for our pets," says Hurley. "It's almost effortless."

But the system is hardly foolproof. For all of the success stories, there also are stories of lost pets whose microchips went undetected by incompatible scanners, leaving shelter workers to conclude that they were unwanted strays. And a recent study suggests that microchips could also present a health risk to some animals.

The cancer scare surfaced in September, when a research paper by Katherine Albrecht, a Harvard-educated consumer-privacy expert, became public. Albrecht reviewed 11 articles about microchips and cancer that had been published in veterinary journals. Six of the articles reported malignant tumors near or around microchips implanted in laboratory mice and rats. Two more reported such cancers in individual dogs. Three others did not find a cancer link.

Based on the findings, Albrecht recommended that policy-makers reverse mandatory microchipping regulations, and said that veterinarians should "carefully consider the potential" of health risks before recommending implants for pets.

About the writer:

• Call the Bee's Cynthia Hubert, (916) 321-1082