A recent hantavirus infection event on an international cruise ship has sparked widespread public concern, highlighting the persistent threat of zoonotic diseases in an increasingly connected world. To provide clarity and authoritative guidance, Professor Li Dongzeng, chief physician at the Department of Infectious Diseases at Beijing You An Hospital, Capital Medical University, has shared critical insights into why these animal-borne viruses are becoming more prevalent.
The Drivers of Disease Spillover
In recent years, the world has witnessed frequent outbreaks of zoonotic diseases, including hantavirus and dengue. According to Professor Li, the root cause is a growing imbalance between human activity and the natural ecosystem. Three primary drivers—global warming, ecological change, and rapid urbanization—interact to accelerate the "spillover" of viruses from animals to humans.
How Global Warming Expands Risk
Rising global temperatures and the increased frequency of extreme weather events, such as heatwaves, droughts, and heavy rains, are fundamentally altering the environment. These changes are expanding the habitat range of rodents, which serve as the natural hosts for hantavirus. As rodents migrate into new areas, they break previous geographic boundaries, increasing the likelihood of human exposure.
A prime example is the Andes virus (ANDV), a hantavirus strain previously limited to South America, which is now spreading to new regions due to rodent migration.
The Hidden Threats in Ice and Heat
The impact of warming extends beyond habitat expansion. The thawing of glaciers and permafrost potentially releases ancient pathogens that have been dormant for millennia. Furthermore, higher temperatures can prolong the survival of viruses outside their hosts, accelerate viral replication within hosts, and enhance overall virulence.
Professor Li notes that unusual winter temperature fluctuations often lead to more severe flu seasons the following year, a pattern that similarly applies to hantavirus and other zoonotic threats.
The 2026 El Niño Alert
Current environmental data suggests a heightened risk period. According to the National Climate Center of the Chinese mainland, the equatorial central-eastern Pacific is expected to enter an El Niño state this May 2026. This moderate-to-strong El Niño event, peaking in the summer and autumn, is anticipated to increase the risks of infectious disease transmission.
By understanding the intersection of climate, ecology, and urban growth, public health experts aim to help the global community move beyond fear toward proactive prevention and informed health management.
Reference(s):
When climate, ecology and urbanization fuel zoonotic diseases
cgtn.com
