Environmental quality and global health

A growing scientific movement is investigating the complex and interconnected relationship between environmental degradation, infectious diseases, and global health, an approach often referred to as “One Health”. This paradigm challenges the long-held assumption that human health exists independently of the planet’s health. In the present review, three major global issues—environmental pollution, biodiversity loss, and climate change—are considered as key drivers of disease emergence and spread. Environmental pollution may affect the immune system, making living species, including humans, more vulnerable to infectious diseases. The COVID-19 pandemic highlighted this link, as studies in Italy and elsewhere correlated higher air pollution levels with increased spread and severity of the virus. Biodiversity loss, according to the “dilution effect” theory, can increase disease transmission. In ecosystems with a wide variety of species, pathogens are “diluted” because their vectors are more likely to encounter hosts that cannot transmit the disease. When biodiversity declines, however, “super-spreader” species that are effective at transmitting pathogens, such as certain rodents and bats, often dominate, increasing the risk of zoonotic spillovers. Finally, climate change exacerbates these issues by expanding the geographical range of disease vectors like mosquitoes and by creating extreme weather events that can lead to outbreaks of waterborne diseases. The present review addresses these issues by describing some key examples, such as the relationship between atmospheric contamination and the outbreak of infectious diseases, the role of biodiversity loss in Lyme disease, and the increase in the range of insect vectors of malaria and dengue associated with climate change. A multidisciplinary approach is fundamental to addressing these global challenges, suggesting collaboration between experts in human and veterinary medicine, developmental biology, environmental science and toxicology, and public policy, as well as the need to raise public awareness. This challenge could also be addressed through the advent of innovative technologies capable of significantly increasing our ability to access large multidisciplinary databases. Among these, artificial intelligence-based technologies could undoubtedly play a leading role.