OKLAHOMA CITY (KFOR) – An epidemic at Oklahoma City Animal Welfare is forcing its doors to close for at least a week while caretakers deal with a rapidly spreading upper respiratory infection among their dog population.

A deep cleaning is underway at their facility in southeast Oklahoma City after an estimated 150 dogs became sick in just a few days, leaving at least four dead.

“It’s life or death, when we say this, it’s serious,” said Jon Gary, Superintendent of Oklahoma City Animal Welfare. “This is the first time we ever have closed a building, but we’ve also never seen anything that spread as rapidly as this is spreading.”

The dire situation is only piled on by being over capacity as well. Gary said they have just short of 400 dogs inside a building that’s meant for roughly 300. Last week, they reached 500.

Gary is urging people to keep dogs away from there.

“We’re asking the community to bear with us through this,” Gary said. “The shelter is the last place any animal should ever have to come, and it should be a last resort.”

The shelter is still taking dogs that are sick and plan to try and isolate them if they can. They are also taking injured dogs and those who pose a threat to the community.

Owners can also reclaim their pet at the shelter if they want to. They are still in the process of reaching out to some foster families who taken dogs from their recently.

One man left the shelter Thursday saying his nephew’s dog they got from the shelter is sick.

“The dog’s got a cough,” he said walking down the steps to his car.

Gary also said treatment includes antibiotics and sanitizing the environment. He’s hoping they can slow the spread, so they can protect the pups and won’t have to close longer.

“We’re going to spend a long time here treating as well as disinfecting and cleaning the building from top to bottom,” he said.

Right now, they are testing and treating all the dogs in the shelter. They sent samples off to find out what exact sickness they’re dealing with. It takes about a week to get those back and they will reassess the situation then.

For more on how you can help, head to the OKC Animal Welfare website.

The Moore Animal Shelter says it will not be accepting strays brought in from the public or owner-surrendered pets until further notice due to the outbreak.