A healthy dog awaits transport Friday by volunteers Ron Waters, left, and Lisa Espinoza at Lied Animal Shelter. Volunteers said some dogs were being removed from Lied to be placed in other shelters. Photos by Ronda Churchill A worker takes disinfection supplies to the Lied Animal Shelter on North Mojave Road on Friday. A Humane Society team has found a serious outbreak of disease at the shelter.

Hundreds of dogs and cats housed at Southern Nevada's regional animal shelter will probably be euthanized after visiting veterinarians discovered a severe outbreak of contagious diseases in the overcrowded facility.

Lied Animal Shelter closed to the public Friday while a team from The Humane Society of the United States began individual examinations of the 1,800 dogs and cats impounded there to determine how many carried deadly viruses that spread quickly in shelter settings.

Although shelter officials were not aware of problems, the Humane Society team noticed dogs and cats suffering from serious respiratory and intestinal diseases shortly after it arrived in Las Vegas on Monday for a four-day site inspection.

"We had animals dying every day," said Kim Intino, director of animal sheltering issues for the Humane Society and leader of the six-member team of vets and other experts who reviewed Lied.

The nation's foremost animal protection group had been invited by Lied to assess shelter operations and suggest improvements. The team planned to finish its paid work Thursday, but instead declared an "emergency" and stayed on Friday to begin corrective measures at the North Mojave Road facility.

"It is common for there to be problems in animal shelters. But we realized the disease situation was grave," Intino said. "We have a situation of animals that have disease and are dying from that disease in large numbers."

Exact numbers were not available, but shelter officials acknowledged they were looking at putting down hundreds of dogs infected with parvovirus or distemper and scores of cats with panleukopenia, often likened to a feline version of distemper.

Humans are not susceptible to the diseases, which attack animals' respiratory systems and intestinal tracts.

Although Intino said she had not previously come across an outbreak of the magnitude found at Lied, shelter leaders said they had not noticed serious problems.

Lied employs a full-time veterinarian at the shelter, but the animal doctor spends almost all work hours performing spay and neuter operations rather than evaluating the animals, said Diane Orgill, executive director of the shelter.

"We didn't realize this was happening," she said.

Orgill said that while the Humane Society's experts might be able to "look at a cat across the room and tell you what's wrong," the diseases at issue can often be difficult to detect.

"There's a lot of things you don't notice right way," she said. "If a dog sneezes but licks before someone sees him, you're not going to notice."

Orgill noted that Lied had invited the outside scrutiny and that the Humane Society had found disease outbreaks in other shelters.

Intino said Friday evening that she could not provide an estimate on how many dogs and cats are affected, because the team was still in the "emergency phase." Humane Society leaders were directing the segregation of sick animals, performing euthanizations and training Lied staffers on how to properly carry on that work after the team departs today.

Vets were finding a much lower rate of disease in the approximately 800 dogs and cats in Lied's adoption park, Orgill said.

Animals infected with the viruses were concentrated in the shelter's intake area, where at any time about 1,000 animals typically spend three to 10 days awaiting pickup by their owner, a spay or neuter surgery, or euthanasia for animals deemed unadoptable.

Orgill said shelter overcrowding undoubtedly hastened the spread of disease.

"The number of animals we have increases the chances of this happening," she said.

It was unclear Friday evening when Lied would be able to reopen its shelter, clinic and adoption park.

When it does, Animal Foundation spokesman Mark Fierro said, the shelter will immediately implement one of the Humane Society's key recommendations for minimizing the chances of further disease spread.

Fierro said shelter employees will immunize animals as soon as they are brought to the shelter by animal control officers or members of the public.

"They were doing that on a select number of animals, and now they'll be doing it for all," he said.

In addition, the shelter will begin using vaccines that spread antibodies through animals' systems faster.

People who have adopted animals from Lied recently and have concerns about their pets' health may bring them in for a checkup or return them permanently, Orgill said.

She encouraged pet owners whose animals have gone missing to visit the shelter in hopes of finding them, adding that reducing overcrowding will significantly help combat the crisis the shelter faces.

"If they've had vaccinations in the past, they're probably going to be fine, but every animal is different," said Orgill, who also serves as president of The Animal Foundation, the private nonprofit that operates the shelter.

The foundation contracts with Clark County and the cities of Las Vegas and North Las Vegas to house abandoned, neglected and stray animals.

More than 7,000 dogs, cats, rabbits, gerbils, guinea pigs and other animals are adopted annually at Lied, and its spay and neuter clinic has performed nearly 200,000 surgeries.

The Animal Foundation generated headlines five years ago amid allegations of mismanagement by then-President Mary Herro and citizens' complaints that their pets were wrongfully euthanized there.

A 2001 investigation by the city of Las Vegas found that management controls at the shelter were inadequate, poorly trained employees had illegal access to controlled substances, and thousands of dollars had been stolen.

The shelter's fortunes seemed to have turned around since it changed directors, boosted and replaced much of its staff and expanded operations.