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.

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.

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

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 have died after contracting bird flu at a Washington State animal sanctuary. The Wild Felid Advocacy Center of Washington in the city of Shelton announced the deaths on December 20. Just two weeks prior, officials confirmed the presence of bird flu in the sanctuary, which forced the center to close and quarantine.

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.

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

Nearly two dozen big cats died after bird flu swept through the sanctuary where they lived. The Wild Felid Advocacy Center near Shelton, Washington said the first animals died last month but the cause was just recently confirmed, KIRO reported. In all 20 cats died, more than half of the sanctuary’s big cats.

The ongoing spread of bird flu in the United States has alarmed experts -- not just because of human cases causing severe illness, but also due to troubling new instances of infections in cats.