Serological signature of tick-borne pathogens in Scandinavian brown bears over two decades.
Lye Paillard, Krista L Jones, Alina L Evans, Jérémy Berret, Maxime Jacquet, Reto Lienhard, Mahmoud Bouzelboudjen, Jon M Arnemo, Jon E Swenson, Maarten J Voordouw
Author Information
Lye Paillard: Laboratory of Ecology and Evolution of Parasites, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland. lye.paillard@unine.ch.
Krista L Jones: Department of Forestry and Wildlife Management, Faculty of Forestry and Wildlife Management, Hedmark University College, Campus Evenstad, NO-2418, Elverum, Norway. kljones@ucdavis.edu.
Alina L Evans: Department of Forestry and Wildlife Management, Faculty of Forestry and Wildlife Management, Hedmark University College, Campus Evenstad, NO-2418, Elverum, Norway. alina.evans@hihm.no.
Jérémy Berret: Laboratory of Ecology and Evolution of Parasites, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland. jeremy.berret@unine.ch.
Maxime Jacquet: Laboratory of Ecology and Evolution of Parasites, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland. maxime.jacquet@unine.ch.
Reto Lienhard: ADMED Microbiologie, Boucle de Cydalise 16, 2300, la Chaux-de-Fonds, Switzerland. reto.lienhard@ne.ch.
Mahmoud Bouzelboudjen: Informatics and Telematics Service, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland. Mahmoud.Bouzelboudjen@unine.ch.
Jon M Arnemo: Department of Forestry and Wildlife Management, Faculty of Forestry and Wildlife Management, Hedmark University College, Campus Evenstad, NO-2418, Elverum, Norway. jon.arnemo@hihm.no.
Jon E Swenson: Department of Ecology and Natural Resources Management, Norwegian University of Life Sciences, Postbox 5003, NO-1432, Ås, Norway. jon.swenson@nmbu.no.
Maarten J Voordouw: Laboratory of Ecology and Evolution of Parasites, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland. maarten.voordouw@unine.ch.
BACKGROUND: Anthropogenic disturbances are changing the geographic distribution of ticks and tick-borne diseases. Over the last few decades, the tick Ixodes ricinus has expanded its range and abundance considerably in northern Europe. Concurrently, the incidence of tick-borne diseases, such as Lyme borreliosis and tick-borne encephalitis, has increased in the human populations of the Scandinavian countries. METHODS: Wildlife populations can serve as sentinels for changes in the distribution of tick-borne diseases. We used serum samples from a long-term study on the Scandinavian brown bear, Ursus arctos, and standard immunological methods to test whether exposure to Borrelia burgdorferi sensu lato, the causative agent of Lyme borreliosis, and tick-borne encephalitis virus (TBEV) had increased over time. Bears had been sampled over a period of 18 years (1995-2012) from a southern area, where Ixodes ricinus ticks are present, and a northern area where ticks are uncommon or absent. RESULTS: Bears had high levels of IgG antibodies against B. burgdorferi sensu lato but not TBEV. Bears at the southern area had higher values of anti-Borrelia IgG antibodies than bears at the northern area. Over the duration of the study, the value of anti-Borrelia IgG antibodies increased in the southern area but not the northern area. Anti-Borrelia IgG antibodies increased with the age of the bear but declined in the oldest age classes. CONCLUSIONS: Our study is consistent with the view that ticks and tick-borne pathogens are expanding their abundance and prevalence in Scandinavia. Long-term serological monitoring of large mammals can provide insight into how anthropogenic disturbances are changing the distribution of ticks and tick-borne diseases.
