Background and Assessment
excessive heat) are associated with air pollution that could result in acute or longterm effects (e.g., asthma, exacerbation of existing conditions).8 Some extreme events can severely disrupt infrastructures (e.g., utilities, transportation, communication) that are critical to accessing health care and emergency services.1 Extreme weather events, in fact, are more likely to cause disruption than death. For example, in 1997 river flooding in central Europe left over 200,000 people homeless and 100 dead.23 Hurricane Katrina—the most expensive natural disaster in US history—left perhaps 1,800 people dead and one million people displaced.24
According to the US Global Change Research Program, “Health risks may… arise long after the event, or in places outside the area where the event took place, as a result of damage to property, destruction of assets, loss of infrastructure and public services, social and economic impacts, environmental degradation, and other factors. Extreme events also pose unique health risks if multiple events occur simultaneously or in succession in a given location. The severity and
extent of health effects associated with extreme events depend on the physical impacts of the extreme events themselves as well as the unique human, societal, and environmental circumstances at the time and place where events occur.”1 For example, after floods, there are increases in diarrheal and respiratory diseases, even in high-income countries.23 Droughts also have wide-ranging long-term effects on nutrition and infectious disease risks.4,5,8,14 Similarly, wildfires (sometimes caused by
Table 1. Vector-borne Diseases That are Likely to be Sensitive to Climate Change Vector
Major Diseases
Mosquito
Malaria, dengue fever, yellow fever, West Nile fever
Sandflies
Leishmaniasis
Triatomines
Chagas disease
Ixodes ticks
Lyme disease and tick-borne encephalitis
Tsetse flies
African trypanosomiasis
Blackflies
Onchocerciasis
Snails (intermediate host)
Schistosomiasis
Source: Table adapted from Table 2, Haines et al.8
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Healthy Generations
Individuals at highest risk for extreme weather events include those living in high-risk areas (coastal areas, flood plains), people with disabilities or other access and functional needs, older adults, low-income people, and some occupational groups.1,8
Vector-borne Diseases (see article by Dorr on page 34) Global warming is likely to change the pattern of vector-borne illness because insects (as well as hosts, like birds and rodents) respond quickly to changes in temperature and moisture by migrating and increasing numbers.5 According to the US Global Change Research Program, “Vector-borne diseases are illnesses that are transmitted by vectors, which include mosquitoes, ticks, and fleas. These vectors can carry infective pathogens such as viruses, bacteria, and protozoa, which can be transferred from one host (carrier) to another. The seasonality, distribution, and prevalence of vector-borne diseases are influenced significantly by climate factors, primarily high and low temperature extremes and precipitation patterns… For example, ticks capable of carrying the bacteria that cause Lyme disease and other pathogens will show earlier seasonal