Erling Meisingset
Research Scientist
(+47) 918 08 860
erling.meisingset@nibio.no
Place
Tingvoll
Visiting address
Gunnars veg 6, 6630 Tingvoll
Authors
Atle Mysterud William Ryan Easterday Vetle Malmer Stigum Anders Aas Erling Meisingset Hildegunn ViljugreinAbstract
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.
Authors
Erling MeisingsetAbstract
No abstract has been registered
Authors
Even Unsgård Erling Meisingset Inger Maren Rivrud Gunn Randi Fossland Pål Thorvaldsen Vebjørn Veiberg Atle MysterudAbstract
No abstract has been registered
Abstract
1. Our understanding of how migratory wildlife populations affect incidence of in-fectious diseases spilling over into humans is limited. Ticks are expanding theirdistribution towards northern latitudes, causing emergence of tick- borne dis-eases. Deer serve as reproduction hosts for adult ticks, supporting the tick pop -ulations. However, in northern areas, deer populations are partially migratory,and migrants occupy high elevation summer ranges that are unsuitable for ticks.Migration can thus theoretically lead to escape from exposure to ticks and to deerfeeding fewer ticks, which lower disease hazard to humans. 2. Combining data on Ixodes ricinus tick abundance with GPS-tracking data of reddeer (Cervus elaphus), we quantified the distributional overlap of ticks and reddeer along elevational gradients in Norway. Furthermore, we correlated bothdeer density and the proportion of migratory deer with the incidence of Lymedisease in humans. 3. We found that migratory deer summer ranges had colder climate and overlappedless with tick distribution than those of resident deer. Deer density consistentlyincreased Lyme disease incidence in humans. However, we found only weak evi-dence that deer migration negatively affected Lyme disease incidence. 4. Our study provides a rare quantification of how host availability, in terms of bothhost density and migratory movement, affects risk of a zoonotic disease.