A Winnipeg cat shelter is dealing with an outbreak of feline parvovirus that has killed at least 45 cats and kittens to date, including one as recently as Monday.

Craig Street Cats says a group of kittens was recently exposed to the virus in a trusted foster home and brought it to the shelter.

Feline parvovirus, also known as feline panleukopenia or distemper, is highly contagious and spreads among cats. It can be fatal, especially among kittens.

"This is a contact virus. You pat a cat and then you touch a door or a doorknob, and you've spread it," Lynn Scott, Craig Street Cats' executive director, told CBC News.

"It goes on your shoes, it lives in the environment for several years. It's a horrible, horrible thing."

Another 100 cats at the shelter are currently in isolation.

Scott said the virus was in Craig Street Cats' facility for less than 24 hours before staff and volunteers realized something was wrong and began sterilizing.

By then, everyone who came in contact with the group of kittens had inadvertently spread the virus around the building because it was on their clothes or shoes, she added.

Kittens most affected

Scott said most of the felines that died were under the age of six weeks, meaning they were too young to be vaccinated.

A smaller number of older cats that died did not have their booster shots, she added.

Scott estimates that the virus has cost Craig Street Cats about $30,000 in medication and veterinary bills and to replace bedding and upholstered items like cat condos and wall perches.

The shelter has started a crowdfunding campaign in the hopes of raising $35,000 for emergency veterinary care.

The YouCaring campaign has raised more than $10,000 as of Tuesday evening.

Scott said it has been tragic to see so many cats die.

"It's taken a huge toll on the staff and volunteers here. It's not unusual to see them leaving crying," she said.

"They get attached to all the critters they care for, and then they pass away and there's absolutely nothing we can do about it."