From People to Panthera:
Big Cats and COVID-19
In March, Nadia, a Malayan Tiger (Panthera tigris jacksoni) at the Bronx Zoo, developed a cough. Over the next week, three other tigers and three lions (Panthera leo) also developed coughs, with some heard wheezing. When Nadia's appetite decreased, she was anesthetized for medical evaluation. Aware of domestic cats positive for COVID-19 in households with infected people, and considering that New York City was the US epicenter for COVID-19 at the time, WCS veterinarians collected swabs from Nadia for analysis at a veterinary laboratory. She tested positive for COVID-19. Fecal testing confirmed COVID-19 in all sick tigers and lions, and showed that one other tiger that was never ill was also infected. The source of infection was a zoo employee who was asymptomatically shedding virus. Fortunately the cats never became very ill, and all have recovered. WCS initiated enhanced preventive measures at our four zoos to protect the health of employees and cats. We tested Nadia out of an abundance of caution, and findings have contributed to the world’s understanding of the novel coronavirus, and helped protect zoo cats.

COVID-19: A Warning Shot from Nature?
Intact, functional ecosystems are the critical foundation of life on our planet. A recent review by WCS shows that ecological degradation, including poaching of wild animals for trade, increases the risk of zoonotic disease emergence from wildlife. Changes at forest edges such as deforestation, road construction and extractive industries raise the chance that humans will be exposed to novel micro-organisms. Conserving and restoring intact ecosystems is critical to halt climate change, biodiversity loss, and to reduce the risk of future zoonotic disease spillover and pandemics. Dr Chris Walzer discusses how we must reset our relationship with nature post COVID-19.

Camelid Health for Communities
Wild camelids in Latin America, including the vicuña (Vicugna vicugna), can suffer from mange causing severe disease and even death. In Bolivia and Peru, our health teams work with Indigenous and Local Communities who rely on vicuña fiber for their income, to monitor vicuña health and improve their management. On comparing parasitological results from the past decade, we have found that parasite loads have decreased in the past year since we began this collaborative effort, indicating that our approach is improving the health status of these vicuñas, which benefits the financial stability of the communities as well.
Mortality Monitoring to Prevent Pandemics
In the Republic of the Congo, a 2005 Ebola Virus Disease (EVD) outbreak had a human mortality rate of more than 80%, and an estimated 5,000 great apes also died. In partnership with the government, WCS set up an early warning system for EVD, working with hunters, forest communities, and rangers to monitor wildlife health through a carcass monitoring and sampling network, whilst promoting best practices in disease risk reduction. The network covers over 30,000 km2 of remote forest in northern Congo, an area home to 60% of the world’s gorillas.
Coronaviruses Increase from Field to Plate
Poaching and commercial trade of wildlife pose a significant risk to global health via the spillover of pathogens from wild animals to humans. Wildlife markets represent super-interfaces with large numbers of mixed species with potential to shed, share, and recombine viruses. WCS recently showed that positivity to coronaviruses in rats traded for food increased along the trade chain from source, to markets, to the plate in restaurants. WCS' Dr Amanda Fine spoke with ABC news on why COVID-19 has placed more attention on the trade in wildlife.
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The Wildlife Conservation Society was among the first zoos in the world to have full time veterinary care for their animals, with a clinician and pathologist hired in 1903 and a zoo animal hospital opening at the Bronx Zoo in 1916. We were also one of the first conservation organizations with a dedicated team of wildlife veterinarians deployed around the world to address the health of free ranging wildlife and problem-solve at the wildlife / domestic animal / human health and livelihoods interface, all underpinned by a foundation of environmental stewardship.

To learn how to support the One World - One Health portfolio at WCS, please contact Dr. Chris Walzer at or Dr. Paul Calle at

Photo Credits: Nadia, Malayan Tiger © WCS; deforestation in Madagascar © WCS; sampling of a gorilla carcass © Alain Ondzie/WCS; rodents traded to Vietnam for human consumption © Lucy Keatts