Climate Change
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Vector Borne Disease and Climate Change

Vector-borne diseases (VBD) are infectious diseases that are transmitted to humans by animals, also called vectors, such as mosquitoes, ticks, fleas, lice, and rodents.  Climate change can cause vectors or the diseases they carry to multiply or spread out more rapidly.  When vectors spread to new areas where people live, work, or play, more people may be at risk of contracting VBD.  This is particularly true when vectors move into places that they have never inhabited before, or conversely, when people move into areas where vectors exist.

How does climate change affect vector-borne disease?

The ecology of Vector-Borne Diseases (VBD) is complex, and climate is a major factor that may influence disease transmission cycles and disease occurrence.  Changes in temperature and humidity can affect where vectors proliferate.  These changes can also affect the life-cycles of the pathogens they carry.

Climate change may impact the distribution of vectors- depending on whether drier or wetter habitats are more suitable for any particular vector- and may allow them to exist where they previously did not.

How do vector-borne diseases impact health?

Human Hantavirus Cardiopulmonary Syndrome (HCPS), Lyme disease, and West Nile virus are three VBD that climate change may impact in California.  As climate conditions change to alter the ecology of vectors, it is possible for human exposure to these diseases to increase significantly.  For example:

Indirect health effects of VBD may include pesticide-related health effects.  Use of pesticides might increase in response to growing populations of disease vectors.  Human exposures to pesticides may cause a wide variety of health effects, depending on the pesticide used and the amount of exposure.

Resources on climate change and vector-borne diseases