News that one of the Bronx Zoo's Malayan tigers tested positive for coronavirus has raised concerns among animal lovers and pet owners, who are wondering how they can coexist amidst a pandemic. The USDA, which helped administer the test, had this sobering advice, "You should restrict contact with pets and other animals while you are sick with COVID-19, just like you would with other people."

Further, the USDA notes, "Although there have not been reports of pets becoming sick with COVID-19 in the United States, it is still recommended that people sick with COVID-19 limit contact with animals until more information is known about the virus. When possible, have another member of your household care for your animals while you are sick. If you are sick with COVID-19, avoid contact with your pet, including petting, snuggling, being kissed or licked, and sharing food. If you must care for your pet or be around animals while you are sick, wash your hands before and after you interact with pets."

The four-year-old female tiger, Nadia, was tested after she and others tigers at the zoo developed a dry cough and showing a decrease in appetite. The tigers were infected by a keeper who had COVID-19 but was asymptomatic while caring for them, according to the Wildlife Conservation Society which runs the zoo. The NY Times reported, "While the zookeepers generally keep a barrier between themselves and the cats, they do get within a few feet of the animals," with the zoo's veterinarian explaining, "During the course of feeding and doing enrichment they will come within feet of them but on opposite sides of the barrier."

Nadia the Malayan Tiger

Nadia was selected as the representative big cat to get tested (because she had to be anesthetized), and she was given a species-specific test, not one meant for humans. She and the other cats are expected to make full recoveries. The test given to Nadia was designed by Dr. Leyi Wang, a veterinary virologist and an expert on coronaviruses in animals.

In early March, health authorities in Hong Kong said that a dog contracted coronavirus from its owner, raising questions and worries about how the pandemic affects animals. Then a cat in Belgium was believed to have COVID-19, after falling ill; one scientist said, "What makes us actually believe that this cat was infected is that there was quite a lot of virus detected in the feces and vomit in multiple tests over several days."

Cats appear to be more susceptible to COVID-19. Steven Van Gucht, a virologist in Belgium and the country's spokesperson for the pandemic, said that the cat appeared to have contracted the disease from its owner. From Live Science:

Cats and humans appear to have a similar "doorknob" on the surfaces of respiratory cells that lets the SARS-CoV-2 virus get inside, according to Van Gucht.

In humans, scientists have figured out that the SARS-CoV-2 virus attaches to a receptor protein called ACE2 that's on the outside of respiratory cells. Once inside of these cells, the virus hijacks certain machinery so it can replicate.  "The feline ACE2 protein resembles the human ACE2 homologue, which is most likely the cellular receptor which is being used by Sars-CoV-2 for cell entry," Van Gucht said.

"The feline ACE2 protein resembles the human ACE2 homologue, which is most likely the cellular receptor which is being used by Sars-CoV-2 for cell entry," Van Gucht said.

Scientists are studying whether variations in humans' ACE2 proteins are why there are varying reactions to coronavirus.

"At this time, there is no evidence to suggest that any animals, including pets or livestock, can spread COVID-19 infection to people," the USDA says.

The CDC has tips about living with animals amidst the pandemic—and if you're not sick, you should still take the same health precautions with your pets as you do during your non-pet moments—like WASH YOUR HANDS.

The Bronx Zoo has been closed since mid-March, and the zoo's essential staffs have been grouped into teams that work one week on, one week off. Additional protocols have been put into place after Nadia's positive diagnosis.