WESTBROOK – Fears of foot-and-mouth disease have prompted Smiling Hill Farm to shut its doors to visitors.

The 500-acre farm is a working dairy farm and normally attracts 100,000 visitors each summer to its petting zoo and animal exhibits.

“This is the only way to ensure the health and safety of our animals,” said Warren Knight, whose family operates the farm on Route 22. “We wrestled with this, but feel like we have no choice.”

Foot-and-mouth is dreaded because it can be transmitted so easily – by dirt on vehicle tires, clothes, shoes, even in the air.

The virus is harmless to humans but destroys animals’ hooves and causes mouth blisters that ruin their appetite.

The United States has not had a confirmed case since 1929.

In Britain, more than a million animals have been condemned to slaughter in an attempt to contain the outbreak, and restrictions have been imposed on tourism events and the movement of animals.

Smiling Hill is believed to be the first farm in Maine to close in response to the disease.

Knight said the farm could lose as much as $250,000 by closing to the public. But, he said, the alternative could be much worse.

“It’s been scary for us to watch them burn entire herds of cattle in England,” Knight said. “Our family’s been farming since the 1600s. This is not something we are taking lightly.”

The farm will continue to sell its dairy products, including milk, ice cream and butter, out of its store on Route 22.