The longer wild mammals remain in trade networks, the higher the likelihood of zoonotic disease spillover to humans, according to a new analysis by researchers at the University of Minnesota’s Center for Infectious Disease Research and Policy (CIDRAP). The study, which examined trade data from 2000-2022, found a direct correlation between trade duration and pathogen transmission risks.
Wildlife markets and trade routes have long been recognized as potential hotspots for disease emergence, with COVID-19’s suspected origins in a Wuhan wet market bringing renewed attention to the issue. The CIDRAP analysis quantifies this risk for the first time, tracking how extended captivity and transport stress animals’ immune systems while increasing human contact points.
‘Each additional week in trade represents more handling events, more mixing with other species, and more opportunities for pathogen shedding,’ explained one epidemiologist familiar with the research. Officials from the World Health Organization (WHO) noted these findings align with their 2021 guidelines recommending reduced wildlife trade durations.
The study comes as 45 countries debate amendments to the Convention on International Trade in Endangered Species (CITES) that could impose time limits on wildlife transport. Conservation groups argue such measures could simultaneously protect biodiversity and public health.
However, implementation challenges remain. ‘Without addressing the root causes of illegal wildlife trade, time restrictions might simply drive the industry further underground,’ cautioned a UN Office on Drugs and Crime analyst. The researchers suggest pairing trade duration limits with enhanced veterinary screening at key transit hubs.