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Journal
Publications
Jenkins. E. J., A. M. Veitch, S.J. Kutz, E.P.
Hoberg, and L. Polley 2006 Climate change and the epidemiology of
protostrongylid nematodes in northern ecosystems: Parelaphostrongylus
odocoilei and Protostrongylus stilesi in Dall’s sheep (Ovis d. dalli).
Parasitology (2006),
132, 387–401.
SUMMARY
We describe the epidemiology of the
protostrongylid parasites Parelaphostrongylus odocoilei and Protostrongylus
stilesi in Dall’s sheep (Ovis dalli dalli) from the Mackenzie Mountains,
Northwest Territories, Canada (65xN; 128xW). Peak numbers of 1st-stage
larvae of both parasites were shed by Dall’s sheep on their winter range
from March until May. In larval development experiments in the Mackenzie
Mountains, peak numbers of infective 3rd-stage larvae of P. odocoilei were
available in gastropod intermediate hosts in August–September. For both
protostrongylids, the majority of transmission likely occurs on the winter
range, with infection of gastropods when they emerge from hibernation in
spring, and infection of Dall’s sheep upon their return in fall. We
validated a degree-day model for temperature-dependent development of larval
P. odocoilei in gastropods, and applied degree-day models to describe and
predict spatial and temporal patterns in development of P. odocoilei and P.
stilesi in northern North America. Temperature-dependent larval development
may currently limit northward range expansion of P. odocoilei into naı¨ve
populations of Dall’s sheep in the Arctic, but climate warming may soon
eliminate such constraints. In Subarctic regions where both P. odocoilei and
P. stilesi are endemic, the length of the parasite ‘growing season’ (when
temperatures were above the threshold for larval development) and amount of
warming available for parasite development has increased over the last 50
years. Further climate warming and extension of the seasonal window for
transmission may lead to amplification of parasite populations and disease
outbreaks in host populations. |
