On April 5, the Wildlife Conservation Society’s Bronx Zoo announced that Nadia, a 4-year-old female Malayan tiger, tested positive for COVID-19. In addition to Nadia, several other big cats are showing signs of respiratory disease. Zoo officials believe an asymptomatic zookeeper likely exposed the tigers and lions to the disease, since the zoo was closed to the public on March 16.
The CDC website described Nadia as the first known case in the United States where an animal tested positive for COVID-19. However, they noted a small number of instances from other countries where pets may have tested positive.
According to the zoo, Nadia developed a dry cough and loss of appetite. In addition, Nadia’s sister Azul, two Amur tigers, and three African lions also had developed symptoms. A press release from the zoo stated that all are expected to recover.
As of Sunday, the four tigers and two lions were the only animals at the zoo who are showing symptoms. Another tiger who also lives at the zoo’s “Tiger Mountain” was not showing symptoms as of Sunday night,
“Our cats were infected by a person caring for them who was asymptomatically infected with the virus or before that person developed symptoms,” according to a press release from the Wildlife Conservation Society’s Bronx Zoo. “Appropriate preventive measures are now in place for all staff who are caring for them, and the other cats in our four WCS zoos, to prevent further exposure of any other of our zoo cats.”
Only Nadia was tested for COVID-19 since the process to safely test a large animal, like a tiger, requires anesthesia. The chief veterinarian noted the cats shared similar symptoms so he didn’t want to subject the other cats to risks associated with the anesthesia.
On Sunday night, the Bronx Zoo tweeted an announcement from Dr. Paul Calle, Bronx Zoo chief veterinarian: “The COVID-19 testing that was performed on our Malayan tiger Nadia was performed in a veterinary school laboratory and is not the same test as is used for people. You cannot send human samples to the veterinary laboratory, and you cannot send animal tests to the human laboratories, so there is no competition for testing between these very different situations.”
“Though they have experienced some decrease in appetite, the cats at the Bronx Zoo are otherwise doing well under veterinary care and are bright, alert, and interactive with their keepers,” said the zoo’s press release. “It is not known how this disease will develop in big cats since different species can react differently to novel infections, but we will continue to monitor them closely and anticipate full recoveries.”
“We tested the cat out of an abundance of caution and will ensure any knowledge we gain about COVID-19 will contribute to the world’s continuing understanding of this novel coronavirus.”
Since Nadia and the other cats likely caught the virus from a human carrier, this raises questions and requires on-going investigation. Both the CDC and USDA updated their websites to respond to this unfolding situation.
According to the CDC website, there have been reports of a small number of pets outside the United States who were reported to be infected with COVID-19. These incidents include a cat in Belgium and two dogs in Hong Kong. Nadia, the Bronx Zoo Tiger, is the first known case of an animal in the US testing positive for COVID-19.
“We are still learning about this virus, but we know that it is zoonotic and it appears that it can spread from people to animals in some situations,” explained a CDC statement. “CDC is working with human and animal health partners to monitor this situation and will continue to provide updates as information becomes available. Further studies are needed to understand if and how different animals could be affected by COVID-19.”
The CDC did update their information page titled “If You Have Animals” in their Daily Life and Coping resource guide.
However, the CDC does recommend that people with COVID-19 limit contact with pets as much as possible out of caution.
The USDA also issued a response:
“Anyone sick with COVID-19 should restrict contact with animals, out of an abundance of caution including pets, during their illness, just as they would with other people. 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. If a sick person must care for a pet or be around animals, they should wash their hands before and after the interaction.”
They also commented that there currently isn’t any evidence that animals are spreading COVID-19 in the US. They do offer guidance for people who observe symptoms in animals in their statement about the tiger who tested positive and their FAQ on testing companion animals.
By Samantha Sied