The Impact of Human Activities on Zoonotic Infection Transmissions

Abstract

As humans expand their territories across more and more regions of the planet, activities such as deforestation, urbanization, tourism, wildlife exploitation, and climate change can have drastic consequences for animal movements and animal-human interactions. These events, especially climate change, can also affect the arthropod vectors that are associated with the animals in these scenarios. As the COVID-19 pandemic and other various significant outbreaks throughout the centuries have demonstrated, when animal patterns and human interactions change, so does the exposure of humans to zoonotic pathogens potentially carried by wildlife. With approximately 60% of emerging human pathogens and around 75% of all emerging infectious diseases being categorized as zoonotic, it is of great importance to examine the impact of human activities on the prevalence and transmission of these infectious agents. A better understanding of the impact of human-related factors on zoonotic disease transmission and prevalence can help drive the preventative measures and containment policies necessary to improve public health.

Keywords: climate change; deforestation; emerging; urbanization; wildlife exploitation; zoonoses.

Figure 1

As deforestation removes the higher levels of forest structure, including the canopy, light, and precipitation, exposure to the previously protected floor level leads to soil erosion and pool formations. The new environmental landscape promotes vector reproduction and expansion. Furthermore, organisms dependent on canopy habitation are now redistributed to ground levels closer to human interactions and have increased migrations towards urban developments. Increased vectors and increased human–animal exposures contribute to an increase in infection transmissions.

Figure 2

Climate change is more than just temperature change. As temperature, precipitation, humidity, and climate patterns become more disrupted, vector and animal patterns become modified in ways that increase human exposure to infectious diseases.