Human-Induced Environmental Change Drives Disease Emergence in Humans and Wildlife

Human-induced environmental change causes significant increases in emerging infectious diseases in both wildlife and human population, says Wildlife Trust conservation scientist Dr. Alonso Aguirre as published in the New York Academy of Sciences journal.

The driving factors of environmental change include deforestation, urban sprawl, transportation infrastructures, climate change, and the control of water resources for dams, canals and reservoirs. Urban sprawl and major road projects can easily cut off and fragment natural landscapes where wildlife was once able to cross freely. Migratory routes are disrupted and the introduction of environmental pollutants threatens species survival.

Over the past 30 years, the World Health Organization (WHO) has recorded over 40 emerging infectious diseases such as HIV/AIDS, dengue fever, malaria, and West Nile virus just to name a few — all resulting from direct or indirect human activities.

“The research shows that not only are people more at risk to diseases but wildlife is also at grave risk suffering from the loss of biodiversity,” said Dr. Alonso Aguirre, lead author on the paper. While habitat loss and pollution have adversely affected wildlife population, diseases like chytrid fungus has wiped out amphibians globally from even the most pristine national parks. Scientists continue to examine the biodiversity loss from pathogen pollution and hope to unlock the chain of causation.

Another leading factor of disease is the prevalence of and inability to monitor illegal wildlife trade. The illegal wildlife trade market opens the door for new disease emergence causing significant health threats to humans, domesticated animals and other wildlife. Pathogen pollution is yet another avenue for disease to travel from species to species — when a new species is introduced to an environment the risks of exposing new diseases to the original habitants of that ecosystem are great. Foreign pathogens create a domino effect of new diseases that could cause devastating effects on already challenged species.

The list of health risks has never been carefully examined until now and research shows a vast number of zoonoses (diseases that jump from wildlife to humans) and even human to animal transmission are on the rise. “It is vital to implement strategies to hasten disease and environmental change, we need consistent long-term monitoring of native species as sentinels of a healthy ecosystem, on-going wildlife health assessments and specific interventions for those species under serious risk,” stated Aguirre.

The growing field of conservation medicine works to analyze, predict and provide solutions for a decaying environment. “We look at ecosystems with a holistic eye, trying to understand how each kind of organism in a habitat interacts with others and how outside forces are causing unnatural changes to this intricate system,” said Dr. Mary C. Pearl, president of Wildlife Trust. “The science of conservation medicine is revealing major signs of the health impact of a stressed global biosphere.”

(Resource: Wildlife Trust)

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