Infectious disease

Climate change will make the battle against infectious disease even harder to win

Infections remain a significant cause of death in most developing countries. Several factors will combine to make this situation worse as the planet heats up.

Malaria, dengue fever, West Nile virus and other insect-borne infectious diseases are expected to increase as a result of climate change. Global warming shifts the geographical ranges of vectors and shortens the incubation time of diseases. Warmer weather and longer frost-free seasons expand the number of insects carrying disease and the period over which people are vulnerable to being bitten. Higher temperatures also help the pathogens within the carriers to multiply.

A strong link has been found between annual rainfall, the number of rainy days and the incidence of malaria in the districts of Rajasthan and Gujarat in India. The El Niño weather phenomenon, which causes increases in rain and stormy weather in central America, has also been associated with spikes in malaria.

Waterborne diseases are likely to increase as a result of climate change, too. Outbreaks of cholera and other diarrhoeal infections can be sparked by the extreme weather events associated with climate change. Hurricanes, typhoons and tornados all exacerbate the poor water and sanitation infrastructure present in much of the developing world. In cases of flooding, untreated sewage is mixed with water supplies and pathogens from sediments are re-suspended.

Populations affected by extreme weather events often migrate to displaced people’s camps. Infectious diseases can thrive in these camps, where people are crammed together with poor sanitation facilities and limited access to clean water.

A prime example is the outbreak of cholera in Haiti that occurred between 2010 and 2013, which killed an estimated 8,000 people. Refugee camps also often feature high levels of sexual violence, which can lead to high infection rates for HIV/AIDS and other sexually transmitted diseases.

As the climate changes and traditional agriculture fails, more and more of the developing world’s population is being driven to slum dwellings on the outskirts of cities. Here, higher population densities combined with poor levels of sanitation and health-consciousness lead to greater levels of tuberculosis, influenza, HIV/AIDS and other infections.

About this resource

This resource was first published in ‘Health and Climate Change’ in January 2009 and reviewed and updated in June 2014.

Health, infection and disease
Health and Climate Change
Education levels:
16–19, Continuing professional development