Climate change is expected to alter the geographic and seasonal distributions of existing vectors and vecto-rborne diseases [Likely, High Confidence].

This finding is from chapter 5 of The Impacts of Climate Change on Human Health in the United States: A Scientific Assessment.

Process for developing key messages: The chapter was developed through technical discussions of relevant evidence and expert deliberation by the report authors at several workshops, teleconferences, and email exchanges. The authors considered inputs and comments submitted by the public, the National Academies of Sciences, and Federal agencies. For additional information on the overall report process, see Appendices 2 and 3.

The approach and organization of this chapter was decided after conducting a comprehensive literature review. Two case studies, Lyme disease and West Nile virus, were chosen as representative examples of vector-borne diseases in the United States for this chapter because of their high incidence rates and the body of literature available on the association between climatic and meteorological variables and occurrence of these diseases.

Regarding human outcomes related to vector-borne diseases, there is a much greater volume of published literature available on meteorological and climatic influences on vectors. As a result, our certainty in how climate change is likely to influence the vectors far exceeds our certainty in how changing climatic conditions are likely to affect when, where, and how many cases of vector-borne diseases are likely to occur.

Although the topic of zoonotic diseases was included in the original prospectus, it was later removed due to space constraints. Additionally, since both West Nile virus infection and Lyme disease are zoonotic diseases, these case studies address concepts that are common to both vector-borne and zoonotic diseases.

Description of evidence base: Vector-borne diseases result from complex interactions involving vectors, reservoirs, humans, and both climate and non-climate factors. Numerous studies explain how climate variables influence the relationships between vectors, animal reservoirs, humans, and other non-climate factors to ultimately influence the spatial and temporal distribution of vector-borne disease.cc7c424e-b684-414f-8896-af2d2fee05b6 77f948ec-3f41-4367-a120-6096a78706f5 2471c8e7-348f-40c2-9a28-0d46d3d1f1df eb0e35fc-5e5e-4df4-900c-b85fc4f26d28 c3fa0d45-e602-4539-b0d8-98516bcee406 8fdde45b-cdd1-49de-b74f-966c15770b2d d8fa9745-f20f-4681-8eec-586cc6b8d369 945868ae-7a42-4c03-aecf-42d9f4b39a65 68125763-fcdc-4e32-81d2-a42e88a85a31 0cdb219f-c600-4fbf-b4c6-2d89f77d2868

New information and remaining uncertainties: It is certain that climate change will alter the geographic and seasonal distribution of existing vectors, pathogens, and reservoirs; the influence of climate change on the timing, prevalence, and location of specific vector-borne disease outbreaks is likely to vary depending on the influence of other significant non-climate drivers of disease occurrence.

Assessment of confidence based on evidence: Based on the evidence that climate change will influence the temporal and spatial distributions of vectors, pathogens, and animal reservoirs, there is high confidence that climate change is likely to alter the geographic and seasonal distributions of vectors and vector-borne diseases.

References :

• Climate variability and change in the United States: Potential impacts on vector- and rodent-borne diseases (0cdb219f)
• A climate-based model predicts the spatial distribution of the Lyme disease vector Ixodes scapularis in the United States (2471c8e7)
• Climatic and landscape correlates for potential West Nile virus mosquito vectors in the Seattle region (68125763)
• Field and climate-based model for predicting the density of host-seeking nymphal Ixodes scapularis , an important vector of tick-borne disease agents in the eastern United States (77f948ec)
• Effect of temperature on Culex tarsalis (Diptera: Culicidae) from the Coachella and San Joaquin Valleys of California (8fdde45b)
• Weather and land cover influences on mosquito populations in Sioux Falls, South Dakota (945868ae)
• Impact of climate variation on mosquito abundance in California (c3fa0d45)
• Climate and Vectorborne Diseases (cc7c424e)
• Regional and seasonal response of a West Nile virus vector to climate change (d8fa9745)
• Increasing habitat suitability in the United States for the tick that transmits Lyme disease: A remote sensing approach (eb0e35fc)