Farmers, consumers shouldn't fret over tiger testing positive for coronavirus, expert says
Pigs, chickens and other livestock not susceptible to infection, Iowa State University scientist says.
A 4-year-old Malayan tiger named Nadia living at the Bronx Zoo was the first known coronavirus infection case of an animal in the U.S., according to the Centers for Disease Control and Prevention.
On March 27, Nadia and six other tigers became ill with a dry cough, one of the main symptoms of COVID-19. The zoo got approval from local and state health departments to take a sample from Nadia to be tested for SARS-CoV-2.
The sample was analyzed at the University of Illinois and Cornell University, and the positive result was confirmed at a U.S. Department of Agriculture lab in Ames, Iowa.
So what does this mean for other animals? And the farmers who raise animals for a living?
Jim Roth, director of the Center for Food Security and Public Health at Iowa State University, said that Nadia's sample made its way to the Hawkeye state because it's home to the official federal laboratory.
"It wouldn't be called positive until the USDA lab in Iowa tested for it," said Roth.
Scientists believe that the COVID-19 disease was transmitted to people from a bat, which Roth said is likely but there's no definitive proof. He said once the disease got in people, it mutated into a human disease and could be transmitted from human to human.
"Since then, it has been shown that it can be transmitted from people to house cats and ferrets," said Roth, referring to experiments reported.
A zookeeper at the Bronx Zoo tested positive for COVID-19 and is believed to have transmitted the disease to Nadia. Roth said it's not clear if COVID-19 could transmit from a cat of any kind to people.
But you have to be concerned that it might," he said.
Pigs and chickens are safe, cattle probably too
According to Roth, scientists have tried infecting both pigs and chickens with the disease and neither became infected. Results for cattle, sheep or goats have not yet been determined.
"If (cattle, sheep or goats) did get infected, we'd probably know about it, because this virus is all over the world now," he said. "We're not hearing anything about infections in livestock or poultry."
When asked if Nadia's infection should still be a concern for livestock producers. Roth said "not at all."
Humans and animals difference
Roth said while diagnostic test kits for animals are regulated by the USDA, human tests for the disease are overseen by the Food and Drug Administration.
He said what separates animal testing from testing on humans is that animals can be intentionally infected, so there are known positives and known negatives. That makes developing a test easier, said Roth.
"A big difference in animal disease than disease in people is that animals aren't allowed to travel across national borders without being tested and making sure they're negative for certain diseases," said Roth.
That strictness has led to diseases like foot-and-mouth-disease, which Roth said exists in 90 different countries, to be eradicated in the U.S. for more than 90 years.
Whereas people -- up until the last couple weeks, are able to get on an airplane anywhere in the world and get off somewhere else without much thought going into their health. That allows for diseases in people to spread incredibly fast, said Roth, and to all over the world.
Applying what we know
"This is a virus we've never seen before, because it didn't exist, so that part is new," said Roth of COVID-19. "But how to manage infectious disease outbreaks is something we've had to deal with in animals quite a lot."
Roth has years of experience working with a team with the USDA and state officials on Secure Food Supply Plans, which include plans for poultry, pork, beef and milk.
"(The Secure Food Supply Plans) are all about how to prevent, prepare for, and respond to new disease outbreaks in the different species," said Roth.
The plans give extensive biosecurity recommendations for producers to implement to keep the food supply safe, which is the message that Roth wants consumers to understand most.
"The food is safe, and that's a really important bottom-line message for the public," said Roth. "Livestock and poultry don't get this disease, and even when you hear a packing plant closes down, it's for the workers' safety. It's not a food safety issue."
Roth said that meat, milk and eggs are all "perfectly safe because those species don't get COVID-19".