Implications of climate change on the distribution of the tick vector Ixodes scapularis and risk for Lyme disease in the Texas-Mexico transboundary region (original) (raw)
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Background/Question/Methods Ticks transmit more pathogen species than any other group of blood-feeding arthropods worldwide, affecting humans, livestock and companion animals. The major impact of tick-borne pathogens on the general public in North America and Europe first became evident with the detection of Borrelia burgdorferi as the causative agent of Lyme disease in the 1980’s. The Ixodes species, e.g., Ixodes scapularis, are competent vectors for B. burgdorferi. Lyme disease is the most prevalent arthropod-borne disease in the US and Europe. Recently the number of reports of infected humans has increased, making Lyme disease acquire a new category as an emergent infectious disease. Lyme disease risk maps have been developed in the US, mainly focusing in the Northeast and Midwest regions of the country. The causative agent, vector, and mammalian reservoirs are distributed throughout the region between the US and Mexico. Nevertheless, no major studies of risk for Lyme disease or ...
International Journal of Environmental Research and Public Health
Climate change has influenced the transmission of a wide range of vector-borne diseases in Europe, which is a pressing public health challenge for the coming decades. Numerous theories have been developed in order to explain how tick-borne diseases are associated with climate change. These theories include higher proliferation rates, extended transmission season, changes in ecological balances, and climate-related migration of vectors, reservoir hosts, or human populations. Changes of the epidemiological pattern have potentially catastrophic consequences, resulting in increasing prevalence of tick-borne diseases. Thus, investigation of the relationship between climate change and tick-borne diseases is critical. In this regard, climate models that predict the ticks’ geographical distribution changes can be used as a predicting tool. The aim of this review is to provide the current evidence regarding the contribution of the climatic changes to Lyme borreliosis (LB) disease and tick-bo...
Feria Arroyo et al 2014 Ixodes scapularis species distribution model
Background: Disease risk maps are important tools that help ascertain the likelihood of exposure to specific infectious agents. Understanding how climate change may affect the suitability of habitats for ticks will improve the accuracy of risk maps of tick-borne pathogen transmission in humans and domestic animal populations. Lyme disease (LD) is the most prevalent arthropod borne disease in the US and Europe. The bacterium Borrelia burgdorferi causes LD and it is transmitted to humans and other mammalian hosts through the bite of infected Ixodes ticks. LD risk maps in the transboundary region between the U.S. and Mexico are lacking. Moreover, none of the published studies that evaluated the effect of climate change in the spatial and temporal distribution of I. scapularis have focused on this region.
Global Ecology and Biogeography, 2010
Aim Ixodes scapularis is the most important vector of human tick-borne pathogens in the United States, which include the agents of Lyme disease, human babesiosis and human anaplasmosis, among others. The density of host-seeking I. scapularis nymphs is an important component of human risk for acquiring Borrelia burgdorferi, the aetiological agent of Lyme disease. In this study we used climate and field sampling data to generate a predictive map of the density of host-seeking I. scapularis nymphs that can be used by the public, physicians and public health agencies to assist with the diagnosis and reporting of disease, and to better target disease prevention and control efforts.
International Journal for Parasitology, 2006
We used an Ixodes scapularis population model to investigate potential northward spread of the tick associated with climate change. Annual degree-days O0 8C limits for I. scapularis establishment, obtained from tick population model simulations, were mapped using temperatures projected for the 2020s, 2050s and 2080s by two Global Climate Models (the Canadian CGCM2 and the UK HadCM3) for two greenhouse gas emission scenario enforcings 'A2'and 'B2' of the Intergovernmental Panel on Climate Change. Under scenario 'A2' using either climate model, the theoretical range for I. scapularis establishment moved northwards by approximately 200 km by the 2020s and 1000 km by the 2080s. Reductions in emissions (scenario 'B2') had little effect on projected range expansion up to the 2050s, but the range expansion projected to occur between the 2050s and 2080s was less than that under scenario 'A2'. When the tick population model was driven by projected annual temperature cycles (obtained using CGCM2 under scenario 'A2'), tick abundance almost doubled by the 2020s at the current northern limit of I. scapularis, suggesting that the threshold numbers of immigrating ticks needed to establish new populations will fall during the coming decades. The projected degrees of theoretical range expansion and increased tick survival by the 2020s, suggest that actual range expansion of I. scapularis may be detectable within the next two decades. Seasonal tick activity under climate change scenarios was consistent with maintenance of endemic cycles of the Lyme disease agent in newly established tick populations. The geographic range of I. scapularis-borne zoonoses may, therefore, expand significantly northwards as a consequence of climate change this century. q
Dynamics of tick-borne disease systems: minor role of recent climate change
Revue scientifique et technique (International Office of Epizootics), 2008
Tick-borne disease systems are very sensitive to climate through the impact of temperature and moisture stress on rates of the demographic processes of ticks. There is no a priori reason, however, to expect tick abundance or seasonal activity patterns to respond to climate change in ways that inevitably increase the risk of infection by the transmitted pathogens. Changing host availability may be more important than climate in determining tick abundance. The credibility of any (inherently untestable) predictions of future system-specific changes will be strengthened if based on satisfactory explanations of the past. Tick-borne encephalitis (TBE) in Europe is presented as a case study: observed patterns of climate change are too similar within and between countries to provide the sole explanation for the extreme spatio-temporal heterogeneity of the marked upsurges in TBE incidence over the past two decades. Instead, a nexus of interacting factors affecting both the risk of infection ...
Increased risk of tick-borne diseases with climate and environmental changes
Canada Communicable Disease Report, 2019
Climate warming and other environmental changes have contributed to the expansion of the range of several tick species into higher latitudes in North America. As temperatures increase in Canada, the environment becomes more suitable for ticks and the season suitable for tick activity lengthens, so tick-borne diseases are likely to become more common in Canada. In addition to Lyme disease, four other tick-borne diseases (TBDs) have started to emerge and are likely to increase: Anaplasmosis; Babesiosis; Powassan virus; and Borrelia miyamotoi disease. Increased temperature increases the survival and activity period of ticks, increases the range of both reservoir and tick hosts (e.g. mice and deer) and increases the duration of the season when people may be exposed to ticks. Other ticks and TBDs may spread into Canada as the climate changes. The public health strategies to mitigate the impact of all TBDs include surveillance to detect current and emerging TBDs, and public health actions to prevent infections by modifying environmental and social-behavioral risk factors through increasing public awareness. Clinical care strategies include patient education, early detection, laboratory testing, and treatment.
Climate and Tickborne Encephalitis
Conservation Ecology, 1998
Climatic changes are projected to alter the abundance, dynamics, and geographical distribution of many vectorborne diseases in human populations. Tick-borne diseases such as Lyme disease and tick-borne encephalitis (TBE) are a growing concern in northern Europe and the United States. The impact of a future climate change on the transmission of tick-borne diseases is not known. To make such assumptions, more empirical data are needed on the relations between short-term fluctuations in contemporary weather and disease incidence. This paper analyzes relations between daily minimum and maximum temperatures, monthly precipitation, and TBE incidence during a 36-yr period in Stockholm County, a high-endemic region for TBE in Sweden. Multiple regression analyses were performed, with temperature variables expressed as number of days per winter or spring-summer-fall season with temperatures above, below, or in the interval between different temperature limits. The limits used for daily minimum temperatures represent bioclimatic thresholds of importance for pathogen transmission. To adjust for the length of the tick's life cycle, each TBE incidence rate was related to meteorological data over two consecutive years. Results reveal that increased incidence of tick-borne encephalitis is related to a combination of two successive years of more days with temperatures permitting prolonged seasonal tick activity and, hence, pathogen transmission (i.e., daily minimum temperatures above 5ºC-10ºC), and a mild winter preceding the year before the incidence year (i.e., fewer winter days with minimum temperatures below-7ºC). Alternative explanations of the results are discussed. Findings of this study suggest that a climate change may extend the seasonal range and intensify the endemicity of tickborne diseases, in particular, at northern latitudes.