Contrasting emergence of Lyme disease across ecosystems.
Global environmental changes are causing Lyme disease to emerge in Europe. The life cycle of Ixodes ricinus, the tick vector of Lyme disease, involves an ontogenetic niche shift, from the larval and nymphal stages utilizing a wide range of hosts, picking up the pathogens causing Lyme disease from small vertebrates, to the adult stage depending on larger (non-transmission) hosts, typically deer. Because of this complexity the role of different host species for emergence of Lyme disease remains controversial. Here, by analysing long-term data on incidence in humans over a broad geographical scale in Norway, we show that both high spatial and temporal deer population density increase Lyme disease incidence. However, the trajectories of deer population sizes play an overall limited role for the recent emergence of the disease. Our study suggests that managing deer populations will have some effect on disease incidence, but that Lyme disease may nevertheless increase as multiple drivers are involved.
Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, PO Box 1066 Blindern, NO-0316 Oslo, Norway.
Atle
A
Mysterud
Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, PO Box 1066 Blindern, NO-0316 Oslo, Norway.
William Ryan
WR
Easterday
Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, PO Box 1066 Blindern, NO-0316 Oslo, Norway.
Vetle Malmer
VM
Stigum
Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, PO Box 1066 Blindern, NO-0316 Oslo, Norway.|Section for Genetics and Evolutionary Biology (EVOGENE), Department of Biosciences, University of Oslo, PO Box 1066 Blindern, NO-0316 Oslo, Norway.
Anders Bjørnsgaard
AB
Aas
Norwegian Institute of Bioeconomy Research, Division of Forest and Forest Resources, Tingvoll Gard, NO-6630 Tingvoll, Norway.
Erling L
EL
Meisingset
Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, PO Box 1066 Blindern, NO-0316 Oslo, Norway.|Norwegian Veterinary Institute, PO Box 750 Sentrum, NO-0106 Oslo, Norway.
Hildegunn
H
Viljugrein
D000818:Animals; D001096:Arachnid Vectors / Q000382:microbiology*; D025065:Borrelia burgdorferi / Q000472:pathogenicity / Q000502:physiology; D003670:Deer / Q000382:microbiology*; D004197:Disease Reservoirs / Q000382:microbiology*; D017753:Ecosystem; D005260:Female; D006801:Humans; D015994:Incidence; D018884:Ixodes / Q000382:microbiology*; D007814:Larva / Q000382:microbiology; D008193:Lyme Disease / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission*; D008297:Male; D009664:Norway / Q000453:epidemiology; D009758:Nymph / Q000382:microbiology; D011156:Population Density