Land Use, Farmed Animals, And Zoonotic Diseases
In December 2019, a new strain of coronavirus, commonly known as COVID-19, was identified in China. Although its origins are not conclusively known, genetic similarities between COVID-19 and another strain of coronavirus found in bats has led many scientists to believe that the disease most likely originated from horseshoe bats, a species native to China.
Zoonotic diseases can come from pathogens in bacteria, viruses, fungi, and parasites. No matter their source, though, they all have one thing in common: they’re due to spillovers from animals to humans. For example, scientists have found that COVID-19 shares a 96% similarity with common strains in horseshoe bats. Without a better understanding of how human interactions with farmed and wild animals affect zoonotic diseases, some experts believe that the number of dangerous infections such as COVID-19 will likely accelerate.
Rising populations lead to expansion into native animal habitats, making it harder for wild animals to find places to live, and forcing them to make their homes very close to human settlements. At the same time, population growth across the world has resulted in more demand for meat and animal products, meaning more animals are farmed in concentrated feeding operations. The low genetic diversity and cramped conditions between animals and humans make them perfect breeding grounds for new zoonotic diseases to emerge.
In this report, researchers predicted how forest fragmentation (breaking forests into smaller portions, usually due to human development), farmed animals, horseshoe bats, and human settlements could possibly create hotspots for zoonotic diseases to grow and develop. Using a special hotspot analysis algorithm, they analyzed 10,000 different areas across Asia, Europe, and Northern Africa. For each of these different areas, they examined farmed animal density, forest fragmentation, cropland cover, horseshoe bat habitats, and nearby human settlements.
Their initial analysis revealed that, compared to the majority of Europe and Africa, China had the most forest fragmentation. Another analysis revealed horseshoe bat habitats and sightings share significant overlaps with human settlements and farmed animal operation areas. By combining data on fragmentation, farmed animals, and settlement patterns, they also determined that many areas in China, especially Shanghai, were at very high risk of becoming hotspots for zoonotic diseases. Parts of Japan and the northern Philippines were also at high risk, while the Mediterranean was at moderate risk and Central Europe and the British Isles at low risk.
Zoonotic diseases are not only dangerous because they can infect humans. They carry the risk of spreading to other animals as well. The authors note how concentrated animal feeding operations pack thousands of animals into cramped facilities. These animals are typically treated with large amounts of antibiotics. In these conditions, antibiotic-resistant superbugs could easily emerge, and if such a disease could infect people, we could become the breeding grounds of a potentially antibiotic-resistant global pandemic.
As advocates, our goal should be to incorporate not only the well-being of animals, but the environment and needs of people as well. The authors of the article recommend reducing our reliance on animal-based diets, and they encourage “One Health” policies, which advocate for holistic views of global health. In addition to promoting plant-based diets, animal advocates could work together to discover ways of supporting human populations without sacrificing nature and animals. How we choose to handle urbanization and our expansion in the future will greatly impact the emergence of newer, deadlier diseases.