Bird flu has been on the rise in Washington state and one sanctuary was hit hard: 20 big cats – more than half of the facility’s population – died over the course of weeks.

The Wild Felid Advocacy Center in Shelton was home to 37 big cats - including tigers, cougars and leopards - before the outbreak began in late November, said Mark Mathews, who co-founded the sanctuary in 2004. Twenty died from the disease - an even mix of elderly cats with previous medical issues and younger, healthier cats.

A wildlife sanctuary in Washington state is under quarantine after 20 big cats died due to H5N1 bird flu infections.

The Wild Felid Advocacy Center of Washington announced it is under quarantine amid a devastating bird flu outbreak that has killed 20 big cats.

The sanctuary in Washington state said it was working with officials to determine the cause of the outbreak, which has killed over half of its cats in recent weeks.

Twenty big cats, including a half-Bengal tiger and four cougars, died between late November and mid-December at a sanctuary in Washington State after becoming infected with bird flu, according to the facility’s director.

Bird flu cases in Washington have spread to an animal sanctuary, resulting in the deaths of 20 big cats and forcing the center into quarantine until further notice. The big picture: Wild Felid Advocacy Center in Shelton is working closely with public health officials to monitor workers and animals after the presence of bird flu (HPAI) was confirmed in some big cats at the sanctuary,

An animal sanctuary in Washington is under quarantine after 20 big cats died amid a bird flu outbreak, the Wild Felid Advocacy Center announced. Read online:

Bird flu ripped through a Washington state wildlife sanctuary, killing 20 big cats, the center said in a Facebook post, calling the deaths a "significant loss."