Climate change affects the spread of disease in a variety of ways. Rising temperatures and rainfall make it possible for diseases that flourish in temperate conditions to increase the area in which they can infect humans and animals. Environments previously too cold for the outbreak of particular viruses have suffered from cases in the past ten years. One such example is the outbreak of dengue fever in Nepal, which was previously too cold for this mosquito-transmitted viral infection. In 2019 the largest outbreak ever was recorded.
Deforestation and the link to the spread of disease
Destructive human activities, such as deforestation, also contribute to both climate change and the outbreak of new diseases. In the last 50 years, 17% of the Amazon forest has been felled to make space for farming. Not only does deforestation destroy natural ecosystems, but wildlife is forced out of their natural habitats into manmade environments, which increases the risk of animal-based viruses transferring to humans. Research from the US Centers for Disease Control and Prevention suggests that three-quarters of new disease infecting humans originate from the animals surrounding us.
Increasing deforestation harms our natural ecosystems and threatens countless species of animal, increasing the chances that we unknowingly become the hosts for new pathogens as they mutate from animal-based viruses into ones that can infect us. COVID-19, Ebola and Sars are three well-known examples of viruses that originated in animals.
Air pollution and the impact on the immune system
Deforestation isn’t the only contributing factor to the rise in the spread of disease. Air pollution also makes it easier for infectious disease to spread faster, thanks to the health impact that fine pollutants have on the human body. Environmental contaminants can alter the body’s immune system response, increasing susceptibility to infectious disease. In some cases, pollutants make vaccines less effect as the body’s immune response is affected. Not only this but these pollutants have been found to make certain bacteria more resistant to antibiotics.
There is an undeniable link between how we treat our earth and our society’s health. The intersection between environmental health and infectious disease means that as our world slowly heats up, our forests are felled and wildlife is pushed to coincide with us in urban areas, there is a rise in dangerous infectious disease. According to The World Health Organisation infectious disease kills 17 million people a year, and this number is on the rise. Economists and futurists predict that by 2050 infectious disease will become the number one killer in the world.