Abstracts - Posters
Projections for Range Spread in Canada of the Lyme Disease Vector Ixodes Scapularis, in Response to Climate Change
Nicholas Ogden1, Abdel Maarouf and Ian K. Barker
1Université de Montréal
nicholas.ogden@umontreal.ca
There is debate as to whether projected climate change is likely to significantly alter the geographic range of arthropod vectors and the pathogens they transmit. Studies on the effects of temperature on development rates of Ixodes scapularis, the tick vector of Lyme disease, allowed us to create a temperature-driven dynamic population model of I. scapularis. We used output from model simulations to investigate the potential for northward spread of the tick under conditions of the IPCC emission scenario SRES 'A2'. Potentially significant increases in range were seen as early as the 2020s, and by the 2080s, the theoretical northern limit for establishment of I. scapularis increased northwards by up to 1000km. In simulations for the most northerly existing I. scapularis populations, the number of ticks that survived each year increased linearly from the present day to 2080, by which time annual tick survival had more than doubles. The threshold numbers of immigrating ticks needed to establish new populations are, therefore, likely to decline, and newly establishing populations may become more common during this period. Seasonality of different tick instars at the northern edge of the ticks' range was consistent with establishment of endemic cycles of the Lyme disease agent. These observations suggest that the geographic range of I. scapularis, and the zoonoses it transmits, may spread significantly across eastern Canada in the face of climate change during this century.
2005-04-06 |
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