Effect of Climate Change on Lyme Disease Risk in North America

Abstract

An understanding of the influence of climate change on Ixodes scapularis, the main vector of Lyme disease in North America, is a fundamental component in assessing changes in the spatial distribution of human risk for the disease. We used a climate suitability model of I. scapularis to examine the potential effects of global climate change on future Lyme disease risk in North America. A climatebased logistic model was first used to explain the current distribution of I. scapularis in North America. Climate change scenarios were then applied to extrapolate the model in time and produce forecasts of vector establishment. The spatially modeled relationship between I. scapularis presence and large-scale environmental data generated the current pattern of I. scapularis across North America with an accuracy of 89% (p<0.0001). Extrapolation of the model revealed a significant expansion of I. scapularis north into Canada with an increase in suitable habitat of 213% by the 2080's. Climate change will also result in a retraction of the vector from southern United States, and movement into the central United States. This report predicts the effect of climate change on Lyme disease risk and specifically forecasts the emergence of a tick-borne infectious disease in Canada. Our modeling approach could thus be used to outline where future control strategies and prevention efforts need to be applied.

Plague dynamics are driven by climate variation

“…More generally, it is widely accepted that the distribution and dynamics of vector-borne infections are particularly sensitive to climatic conditions, by virtue of the sensitivity of the (arthropod) vectors themselves to variations in temperature, humidity, and often quantities of standing water used as breeding sites. This work has been dominated by mosquito-borne infections such as malaria and dengue and by tick-borne infections such as Lyme disease and tick-borne encephalitis (22)(23)(24)(25). Much less attention has been focused on flea-borne infections or on direct effects on the (vertebrate) wildlife reservoirs.…”

Rocky Mountain Spotted Fever in the United States, 2000–2007: Interpreting Contemporary Increases in Incidence

“…29,49 Some researchers have speculated that increases in tick-borne diseases may be fueled by ecologic or climate changes, 50,51 and an increase in actual disease is clearly supported by some focal patterns of recent RMSF emergence. 25 However, the findings from our study suggest that the increase in reported RMSF incidence further involves a complex interplay of physician awareness, diagnostic practices, and reporting policies.…”

Lyme Disease Propelled by Borrelia burgdorferi-Infected Blacklegged Ticks, Wild Birds and Public Awareness ─ Not Climate Change

“…Brownstein et al used a climate-based suitability model to forecast the effect of climate change on I. scapularis expansion in Canada [42]. These authors assumed that established populations of blacklegged ticks were limited to a small number of foci in southern Ontario, but their assertions are unverifiable.…”

“…Ironically, blacklegged ticks were already in central Canada prior to 1970 [34]. Since the benchmark parameters are incorrect, forecasts of a 213% increase in I. scapularis foci further north in Canada by the 2080s [42], are misleading. Moreover, any studies on ticks and climate change have been inconclusive.…”