Antibodies against tick-borne pathogens in domestic dogs in Norway: Borrelia burgdorferi sensu lato, tick-borne encephalitis virus, and Anaplasma phagocytophilum.

BACKGROUND: Ticks are important vectors of zoonotic pathogens, posing a growing threat to animals and humans in Europe. In Norway, the tick species Ixodes ricinus is expanding its range, increasing the risk of tick-borne infections. This study aimed to estimate the seroprevalence of IgG antibodies against Borrelia burgdorferi sensu lato (s. l.), tick-borne encephalitis virus (TBEV), and Anaplasma phagocytophilum in domestic dogs residing in Norway, and to assess their potential role as sentinel species for tick-borne pathogen surveillance at the northernmost limit of I. ricinus' geographical range. Serum samples (n = 433) from domestic dogs were collected across 15 counties between 2016 and 2023 and analysed using immunoblot assays.

RESULTS: Overall, 38% of the dogs were seropositive for one or more tick-borne pathogens. The seroprevalence was 20% for B. burgdorferi s. l., 19% for TBEV, and 11% for A. phagocytophilum. Statistically significant regional differences were observed for the latter two pathogens.

CONCLUSIONS: The findings indicated widespread exposure of Norwegian dogs to tick-borne pathogens and support their role as sentinel species for assessing human risk. Continued surveillance and preventive measures are recommended to reduce tick infestation and pathogen transmission to both dogs and humans.