Science with Sabrina

Why Our Changing World Needs Attention to Microbes

Over the past few decades, we have observed the rise of Emerging Infectious Diseases (EIDs). These are illnesses caused by novel pathogens entering human populations. These diseases have drawn our collective gaze to the unseen world of microorganisms. Among EIDs, an astonishing 71.8% originate from non-human animals, demonstrating how deeply interconnected human and wildlife health truly are.

The Role of Urbanization and Agriculture in Disease Emergence

Our rapidly urbanizing world plays a key role in the emergence of new pathogens. By 2050, the United Nations predicts that 68% of the global population will live in urban areas. However, converting natural landscapes into cities and farmland significantly impacts biodiversity. It disrupts ecosystems and increases the abundance of species that can carry diseases. For example, urban and agricultural development often lead to declines in overall wildlife populations but increase the diversity and abundance of zoonotic hosts — animals capable of transmitting diseases to humans.

Studies show that the homogenization of land use — the creation of similar urban and farm landscapes — drives these changes. This reshaping of ecosystems creates a perfect storm for pathogen transmission and cross-species spillover. In other words, as we transform natural habitats, we inadvertently set the stage for emerging diseases to thrive and spread.

The Mutation Game: Why RNA Viruses Are Especially Dangerous

Not all pathogens are created equal. RNA viruses, like the coronavirus family, are particularly worrisome due to their high mutation rates. These viruses mutate 100 times faster than DNA viruses because their replication machinery lacks proofreading capabilities. Every time an RNA virus replicates, errors accumulate in its genome. In just four days, an RNA virus can replicate approximately 2,765 times. This process introduces numerous mutations.

When outbreaks occur among thousands of individuals, the sheer number of mutations skyrockets. This increased mutation potential creates opportunities for viruses to undergo recombination, where significant genetic changes can produce entirely new viral species. These genetic shifts often result in pathogens that our immune systems struggle to recognize, as seen during the COVID-19 pandemic.

Managing the Risk of Zoonotic Spillovers

Preventing zoonotic diseases requires proactive measures. Land-use changes must consider the health of ecosystems and wildlife to minimize opportunities for pathogen transmission. Best practices include:

• Limiting deforestation and preserving wildlife habitats.
• Ensuring clean drinking water and proper sanitation.
• Reducing interactions between humans, domestic animals, and wildlife.
• Eliminating standing water to prevent mosquito-borne diseases.
• Banning bushmeat consumption to reduce exposure to novel pathogens.

These steps not only protect human populations but also limit the opportunity for pathogens to mutate in wildlife hosts, reducing the overall risk of a pandemic.

Learning from the Past to Protect the Future

Emerging infectious diseases are on the rise. Viruses like Ebola, Nipah, HIV, and SARS-CoV-2 have shown us the devastating consequences of zoonotic spillovers. The challenge is complex, involving economic, ecological, and public health considerations. Yet, solutions are within reach. By investing in research to understand wildlife populations and their associated pathogens, we can identify risks before they become crises.

As we continue to reshape our planet, we must prioritize strategies that protect both human and wildlife health. It’s not just about preventing the next pandemic; it’s about fostering a future where humans and ecosystems coexist harmoniously.