POTSDAM — A ringworm outbreak has led the Potsdam Animal Shelter to close its doors temporarily.

Infected animals are being quarantined and treated while staff and volunteers clean the facility from floor to ceiling.

"It could have been brought in by an animal or a human, and the incubation period is four weeks, so this could have come in a month ago," said Bonnie S. Boyd, president of the Potsdam Humane Society's board of trustees. "We're Cloroxing everything top to bottom for the next few days."

Ringworm is a skin infection caused by a parasitic fungus, similar to athlete's foot. It is easily treated, but is contagious and can spread from pets to humans and vice versa.

"We pride ourselves on having a very clean facility," Ms. Boyd said. "Those spores unfortunately aren't neon orange, so you can't see them."

Ringworm symptoms include itchy, red, raised patches that may blister and ooze.

Ms. Boyd said that it first spread among the shelter's cats, but a dog that was adopted there on Aug. 7 is also being treated for the infection.

To avoid a "vicious cycle" of infection, the society decided earlier this week to stop accepting admissions. It separated the shelter's healthy animals from the infected ones and began treatment while cleaning the entire building.

"This hasn't happened since way back — definitely not since any of us have been around," Ms. Boyd said.

Because this summer has been especially damp and warm, conditions have been good for the fungi that cause skin infections like ringworm to flourish, said shelter volunteer Ann E. Smith.

"A couple local vets have told us this is a particularly bad year for this. It's not just the shelter," she said.

The shelter hopes to open back up for admissions Thursday. Staff expect about four dogs and more than a dozen cats to be surrendered at that time.

Infection outbreaks like this one will be easier to contain once the society's planned expansion gets under way this spring, Ms. Boyd said.

The shelter hopes to add a wing that will include an isolation area for all newly-admitted strays, as well as an expanded surgical room and an air filtration system.

"If we had a true isolation area, we wouldn't have missed a heartbeat," she said.

In the meantime, the humane society is in dire need of people willing to foster animals either while they recover from the skin infection, or to keep healthy cats and dogs away from the sick population.

If you want to donate, volunteer or drop off an animal, call the shelter at 265-3199.