African Swine Fever (ASF) is a highly contagious and fatal viral disease of domestic and wild pigs, with origins in sub-Saharan Africa. ASF emerged in farmed pigs in China in 2018, spread to Southeast Asia in 2019, and has since exploded across the region. There is a high risk for spillover of pathogens from domestic to wild pigs around the villages bordering forests, and a wildlife health surveillance network (WildHealthNet) that WCS has been developing with the governments of Lao PDR, Cambodia and Viet Nam recently helped identify the first cases of ASF in wild boar in Southeast Asia. Monitoring wildlife diseases is vital to enable rapid implementation of appropriate biosecurity measures. The islands of Southeast Asia are home to 11 highly unique, endemic pig species whose survival is now threatened by ASF. These wild pigs also serve essential roles within their ecosystems, tilling the soil and encouraging plant growth, and being key prey species for critically endangered predators, including the Sumatran tiger (Panthera tigris sumatrae). Declines of wild pigs can thus trigger cascading impacts for endangered carnivores, plant communities, and the livelihoods of millions of people.

Over a decade ago, WCS recognized that there was a clear need to adapt and apply molecular technologies to diagnose, discover, and understand the significance of infectious diseases in wildlife. To bridge this gap, we created a zoo-based molecular diagnostics laboratory, one of only a few in the world, at the Bronx Zoo’s Wildlife Health Center. Our goal is to use molecular-based tools to support our conservation efforts, to better understand animal health, and to detect and discover disease risks in wildlife. Read more about a decade of the molecular programs' most fascinating discoveries, from using E-DNA to seek endangered species, to illegal wildlife trade, to biodiversity surveys on Mount everest.
Ecological degradation, land-use change for agricultural intensification or other industrial expansion, wildlife trade, and wildlife markets, all contribute to increasing contact rates between wildlife and humans, and wildlife and domestic animals, and thus increase the risk of disease spillover from wildlife, particularly when they occur in areas of high biodiversity. Intact and functional ecosystems provide the infrastructure for all life, health, and well-being on our planet. Biodiversity conservation must be prioritized, and better integrated into One Health approaches to "build-back-better", in order to build resilience and prevent the emergence of novel zoonotic disease pandemics.

It's estimated that over 400 million domestic dogs roam unsupervised globally, either because their owners allow it, or because they simply no longer have an owner. This free movement of dogs in rural environments can have severe impacts on livelihoods, public health and conservation; through the transmission of diseases, predation and by competition with native species. Dogs have been incriminated in the extinction of at least 11 species, and jeopardize around 188 threatened species. WCS implements collaborative, One Health approaches to tackle threats to humans, livestock and wildlife posed by feral and owned free-roaming dogs in the landscapes where we work.
WCS' New York Aquarium recently received “Sidney”, an orphaned Pacific harbor seal (Phoca vitulina richardsi), that had been rescued and cared for by the Pacific Marine Mammal Center (PMMC) in Laguna Beach, CA. She had been born prematurely, and still had her umbilicus attached when found abandoned on the beach last February. Because of her young age, she could not develop skills to survive in the wild and was in need of a good home, so the New York Aquarium stepped in. COVID-19 delayed Sidney's travel for 5 months, meaning a more complex process for a much larger pup, but she is now safely and happily settled in to her new home.
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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: Babirusa © Julie Larsen Maher/ WCS; molecular discovery © WCS; Bolivia's Tacana Indigenous territory © Omar Torrico/WCS; Feral dog © WCS Chile; 'Sidney' the harbor seal © WCS