Infectious disease will thrive in a warming world. Can healthcare systems cope?

Climate change is costing more than just the earth. Human health is suffering as a result of deforestation and a warming planet.

T he negative ways in which humans interact with the environment are not just damaging the planet, but also causing a health crisis. Climate change and deforestation are making more of us ill. What can we do to stop it?

Infections are jumping from animals to humans

Over 25 million people have contracted COVID-19, and scientists believe more pandemics are sure to follow. It’s in part due to the way we use the environment. Evidence suggests COVID-19 is zoonotic, meaning it originated in animals before jumping to humans. There has been an increase in such diseases over the last few decades, and now around 60% of new infectious diseases are zoonotic

As humans encroach further into animal habitats, using them to build new homes, to grow crops, and to graze farm animals, we are coming into more frequent contact with animals that we don’t usually encounter. Any virus that is ready to make the leap from animal to human has ever greater opportunity. 

But, it’s not just how we use the land that is causing problems. The wider impact of climate change is changing the spread and range of other infectious diseases.

Disease carriers are spreading to new areas

Some insects and animals, called vectors, carry diseases which can infect humans. Every vector has its ideal environment, perhaps preferring warm parts of the world to cold, humid spots to dry. As the climate changes, it is making new parts of the world more inviting for some vectors to live. And if disease-carrying insects and animals start to spread to new homes, so does disease. 

Mosquitos, for example, generally love warm, wet places. With higher rainfall and increasing temperatures across the world, new regions are becoming attractive spots for mosquitos to live and breed. Different species of mosquito acts as vectors for a number of diseases, including malaria, dengue fever, and Zika. 

Take Odisha state in India where, over recent years, the annual heavy rains have lasted longer and longer. This has led to extended breeding periods for the resident mosquitos, which in turn has meant a longer period of time when mosquitos are active and transmitting malaria. The region is seeing far more cases than it would usually expect, putting pressure on local healthcare providers. 

Or we can look at ticks – common in the USA, but previously rare in the historically cooler Canada. Climate change has driven average temperatures up in Canada and ticks are moving in, bringing Lyme disease with them.

Changing weather patterns puts pressure on existing infrastructure

Other diseases are spread by drinking contaminated water. Climate change has led to higher rainfall in countries where the plumbing systems aren’t built for such high levels. In the Netherlands, a 33% increase in gastrointestinal illness was associated with sewage overflowing into drinking water after heavy rainfall.

We need individual, national, and international approaches to the challenge

Adaptions to these new health challenges must happen at an individual, governmental, and global level, and will involve a lot of collaboration. 

Individual actions such as listening to public health advice to wash hands, wear face masks, and use mosquito nets will help keep communities safe. 

National initiatives will involve monitoring disease outbreaks, tracking weather patterns, and studying health data from previous years to help predict future health events. Different sectors, such as meteorological organisations and scientific research centres should work together to strengthen these activities.  

Countries already affected my malaria are putting these ideas into action. The Uganda Malaria Surveillance Project has developed a model that can be used to predict malaria outbreaks using weather information and past data, while the Solomon Islands Meteorological Service and the Vector-Borne Disease Control Programme have worked collaboratively to use rainfall data to provide an early warning system for malaria season. 

On a global level, countries need to work together to communicate and share information about infectious disease outbreaks to slow and stop its spread. Longer term, global initiatives such as One Health and Ecohealth Alliance are bringing governments and non-profits together to incentivize countries and industry to work in a more environmentally friendly way, reducing the behaviors that lead to climate change in the first place. 

It is only by adapting our health system to predict and prevent disease spread, and taking long-term steps to limit human harm to the environment, that we will reduce the health cost to us all. 

The ideas presented in this article aim to inspire adaptation action – they are the views of the author and do not necessarily reflect those of the Global Center on Adaptation.

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