7 more animals at Bronx Zoo test positive for coronavirus: How zoos can help us learn about COVID-19

NAPLES, CAMPANIA, ITALY - 2020/04/06: A employee of the Naples zoo takes care of a tiger. The Naples zoo, which is now closed according to the provisions contained in the security decrees for the fight against Coronavirus (COVID-19), has launched the "suspended ticket" campaign, in practice you can buy the ticket now and come to see the animals when the zoo is reopened, to support the expenses that the zoo has also in this closing period. (Photo by Roberta Basile/KONTROLAB/LightRocket via Getty Images)
The Brox Zoo confirmed Wednesday that three other tigers and three lions that had exhibited similar symptoms — such as a cough — had also tested positive for COVID-19. Additionally, one tiger that never developed a cough also tested positive. (Photo: Getty Images)

Two weeks after the USDA and Bronx Zoo announced Nadia, a Malayan tiger, had tested positive for the coronavirus, the zoo confirmed Wednesday that three other tigers and three lions that had exhibited similar symptoms — such as a cough — had also tested positive for COVID-19. One tiger that didn’t have a cough tested positive too. All eight animals “continue to do well” and are “behaving normally, eating well and their coughing is greatly reduced,” the Bronx Zoo shared.

Scientists are learning about COVID-19 in real time, months after Chinese officials reported the first cases out of Wuhan. Every day it seems there’s a new symptom to look out for in humans, and there have been conflicting reports over the past few weeks as to whether pets are susceptible. (On Wednesday, two cats in New York tested positive for COVID-19, making them the first pets in the United States confirmed to have coronavirus disease.)

Related Video: Bronx Zoo Confirms 8 Cases of Coronavirus in Lions, Tigers

But there might be a resource to help researchers understand more about the current disease threat. The Bronx Zoo’s former chief pathologist, Dr. Tracey McNamara, spoke to Yahoo Life about how zoo surveillance could provide an opportunity to learn about the virus.

“I’ve been working with the federal government early since this whole outbreak and asked them — given that it was a zoonotic disease — when were people going to look at dogs and cats and zoo animals? I suggested zoos would be a perfect microcosm of the animal kingdom if you wanted to get information on species susceptibility,” she shared. (Zoonotic diseases are caused by germs that spread between animals and people.)

McNamara, who is a professor at the College of Veterinary Medicine at Western University in California, played a crucial role in investigating 1999’s West Nile virus outbreak. She previously told Yahoo she’s “not at all surprised” that a tiger tested positive for COVID-19, and that it was a matter of time before the virus was confirmed in pets. She explained how zoos are a breeding ground for research.

“With West Nile virus, we had shown that zoos were ideal epidemiological monitoring sites because every major zoo in every major city has veterinary staff; the animals are looked at constantly by keepers … so if an animal falls ill, it’s not going to be missed,” McNamara explained. “Every animal in an accredited zoo must be [necropsied], the animal equivalent of an autopsy. It’s a gold mine, and with West Nile, we had everything public health needed. I suggested if you really want to get a handle on which species are susceptible to this virus, you should consider starting surveillance in zoos.”

McNamara, who was a scientific adviser on the 2011 film Contagion, broke down how exactly zoo animals could provide more information about COVID-19. Several zoos around the country have veterinary pathologists on staff, doctors of veterinary medicine who diagnose diseases by examining animal tissue and body fluids. These veterinary pathologists are experts at necropsies.

“If zoo animals die from this, and if we can develop the ‘Easter egg dye’ — the immunohistochemical staining, that when you look at the tissues under the microscope it makes the tissues brown — that tells you where the virus is. That’s where you learn about the pathogenesis of this virus. What does it do? What tissues does it target?” McNamara shared. “All of that comes out of pathology studies, which have also been noticeably absent in the human literature.”

McNamara pointed to a Chinese study published in the Lancet, a peer-reviewed general medical journal, that “only” looked at autopsy results of three tissues.

“That’s not how I was trained, and that’s certainly not the approach I would take with a novel disease threat,” she stated. “You have to look at every tissue, every time. Veterinary pathologists in zoos do that. I’m certain that now [COVID-19] has popped up in large cats, that every zoo in the United States is going to be on point looking for unusual symptoms and illness in the animals in their care, and that they will be taking all the biosecurity steps necessary because zoos are also extremely attuned to that and it will be handled properly.”

McNamara continued, “The question now is whether zoos will get the support they need to be able to do the work — this will be extra work. It would be such a missed opportunity if we don’t make sure that we at least have the samples we need to pursue the questions that are being asked.”

McNamara’s suggestion lines up with how the Bronx Zoo handled its infected animals. The zoo announced samples used for testing Nadia were collected from her nose, throat and respiratory tract while she was under anesthesia. Testing was done on the other animals presumed to be infected using a fecal sample test developed by the zoo’s laboratory partners that does not require the animals to be placed under anesthesia.

“We tested the tigers and lions 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,” the Bronx Zoo said in Wednesday’s update. “The testing of these cats was done in veterinary laboratories, and resources used did not take from those being used for human testing.”

The Bronx Zoo thanked the New York State Diagnostic Laboratory at Cornell University and the University of Illinois College of Veterinary Medicine Veterinary Diagnostic Laboratory, “where the initial COVID-19 testing of samples was performed,” as well as the USDA National Veterinary Services Laboratory, “where confirmatory testing was conducted.”

One crucial thing McNamara wanted to point out is that animals found in crowded urban centers, such as zoos, do not fall under the jurisdiction of any federal agency.

“No federal agency has responsibility to dump surveillance on these animals. The only animals under surveillance in the United States, really, are cows, pigs and chickens. That’s through the USDA and that’s because they have value from an economic point of view for agriculture,” she explained, noting how other animals shouldn’t be overlooked.

“Dogs, cats, rabbits — all sorts of small animals have provided early warning for chemical and biological threats over and over and over, but right now we have no way to pick that up because we cannot do real-time epidemiological surveillance in companion animals or in zoo animals or in shelter animals,” she added. “We can’t detect a signal that something unusual is going on.”

McNamara acknowledged the “biggest impediment” right now in testing animals is the lack of diagnostics. “We’re having trouble testing human beings!” But she emphasized that “zoos excel” in obtaining samples, which could be used for later testing.

“Every time they have their hands on [a zoo] animal they take blood samples; they take all sorts of samples. Normally, we have to anesthetize these animals to be able to handle them, so we make the most of every opportunity to obtain some data and then we bank it,” she explained. “So my recommendation would be, even if we can’t launch into zoo surveillance today, there’s nothing stopping zoos from starting to bank samples for later testing.”

McNamara added, “As I’ve said, it’s sort of fallen on deaf ears — I think the zoos represent an opportunity to do some excellent surveillance.”


For the latest coronavirus news and updates, follow along at https://news.yahoo.com/coronavirus. According to experts, people over 60 and those who are immunocompromised continue to be the most at risk. If you have questions, please reference the CDC and WHO’s resource guides.

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