BRUNSWICK — Midcoast Humane closed its Brunswick shelter to the public Tuesday after some of the cats appeared sick.

“We have seen symptoms (upper respiratory infection, fever, not eating) in some cats in each room housing cats in our adoption area and the hallway, and want to make sure it does not spread any further,” states Kate McHugh-Westfall, the volunteer manager for Midcoast Humane, in an email to volunteers.

Mandie Wehr, the veterinarian in charge of shelter operations, confirmed Tuesday that six of the roughly 50 cats up for adoption at the Range Road shelter were showing signs of an upper respiratory illness — which is essentially a cold. While the cats are vaccinated against respiratory infections, it’s not 100% effective against all strains, similar to humans who get a flu shot.

She likened the shelter to a daycare center. As one child gets sick, it soon spreads throughout the classroom.

It’s not unusual for cats to get upper respiratory infections and the shelter sees “kitty colds” every year, Wehr said.

What is unusual is that cats have fallen ill in all four of its adoption rooms, Wehr said.

It’s the first time the shelter has seen so many cats become sick all at once and because it happened in the adoption areas, “we just want to be cautious and do everything we can to make sure we’re adopting out healthy animals,” Wehr said.

Cats can carry and spread a virus and may not show symptoms. Often they will show symptoms when introduced to a stressful environment like an animal shelter, or a new home, Wehr said.

It’s a reminder for staff to encourage guests to use hand sanitizer in between rooms, Wehr said. When people visit the shelter, they move in and out of the rooms, “petting and loving on cats,” which can spread viruses and pathogens.

Shelter staff will deep clean the shelter on Tuesday and Wednesday, disinfecting against any viruses or pathogens and moving animals to clean break spaces.

“This will also give us a chance to get a better, more structured plan in place before opening to the public again on Thursday,” the email states.

Cat adoptions at the shelter are temporarily suspended until the shelter identifies the illness. Test samples will be sent to a laboratory Tuesday to confirm the animals haven’t been infected with any atypical viruses or pathogens. Wehr expects results later this week.

Meanwhile, treatment varies from animal to animal and may include fluid, antibiotics and other medications to help with inflammation and fevers.

“We look at each cat individually and make a plan for that cat,” Wehr said.

It is expensive to treat every cat that gets sick with a cold, Wehr said, “so donations are certainly always appreciated.”

Wehr encourages anyone who recently adopted a cat showing cold symptoms to call the shelter.

“We are are also working to separate animals exposed to this illness from new animals coming in that have not yet been exposed,” according to McHugh-Westfall.

Cat caretakers can still volunteer at the shelter during the closure and will be asked to help clean while wearing personal protective equipment such as gloves, protective shoe coverings and medical gowns until the illness is under control.

All volunteers are reminded to disinfect their hands between handling each animal. For those volunteers with cats at home, McHugh-Westfall urges volunteers to wash their hands thoroughly before leaving home and to change clothes as soon as they get home from the shelter.

The shelter will be open for dog adoptions again starting Thursday. Just when cat adoptions will reopen depends on how the cats are feeling as well as lab results, Wehr said.

dmoore@timesrecord.com