“We’ve never had anything like it; they usually die basically of old age,” said Mark Mathews, the founder and director of the Wild Felid Advocacy Centre in Shelton, Washington. “Not something like this, it’s a pretty wicked virus.”
Three other cats had recovered from the virus, and one remained in critical condition on Tuesday, he said.
The sanctuary said in a statement on Friday that the facility was under quarantine and would be closed until further notice while the habitats were sanitised.
“The virus began to present itself in November within the cougar population, with several cats developing pneumonia-like symptoms. Within days, other species began to show signs of illness,” reported The New York Times on the deaths on Tuesday.
In California, the battle against avian influenza A (H5N1) intensified amid spreading infections across dairy farms and a growing number of human infections, including two newly confirmed cases in Stanislaus and Los Angeles counties, reported Xinhua.
The virus, commonly known as bird flu, has infected 659 of California’s 984 dairy operations since August, with one-quarter of these cases emerging in the past month alone, according to California authorities.
The rapid spread through the state’s dairy industry prompted governor Gavin Newsom to declare a state of emergency last week to protect agricultural workers and public health.
“This proclamation is a targeted action to ensure government agencies have the resources and flexibility they need to respond quickly to this outbreak,” Newsom said in a statement.
The outbreak’s human impact has grown increasingly severe, with California reporting at least 36 confirmed cases – more than half of the nation’s total of 65, according to the latest report by the US centre for disease control (CDC) on Tuesday, though the actual count is likely higher as recent local confirmations may not yet be reflected in federal data.
Two new cases were confirmed Monday in California’s Los Angeles county and Stanislaus county. Both individuals were exposed to livestock infected with bird flu at a worksite, and both had mild symptoms and were treated with antiviral medications, according to the two counties’ health departments.
Public health officials have been monitoring wastewater across the state, detecting the virus in several bay area locations, including San Francisco, Napa, and San José. However, California state epidemiologist Erica Pan explained to ABC30 that these detections might be primarily due to “residential or other commercial milk dumping down in the sinks.”
Although health officials said the risk remains low for the general public, the virus kills 90 to 100% of infected poultry and about 1 to 2% of cows. California state veterinarian Annette M. Jones noted that infected cows may never fully recover.
As the country’s largest dairy producing state, California faced a heavy economic toll from the bird flu outbreak. The virus has led to quarantines and increased testing requirements. The authorities said the state is now testing its 1.7 million cows weekly.
California’s milk production dropped 9.2% in November from the same month last year, the most significant decline recorded, according to the monthly milk production report released by the US department of agriculture (USDA) on Dec 19. Meanwhile, California’s reduced output has led to a 1% decrease in national milk production, raising concerns over US dairy product availability and costs.
The state’s poultry operations have also been hit hard. The California department of food and agriculture reported that 51 commercial poultry operations and nine backyard flocks across the state had been affected.
The virus has also appeared in unexpected places, with Los Angeles county confirming two cases in domestic cats that consumed contaminated raw milk.
The USDA has implemented new containment measures, including a mandatory national milk testing programme announced on Dec 6. However, some experts questioned whether these measures were sufficient.