Brucellosis emergence in the Canadian Arctic.

Brucellosis is an important zoonotic disease affecting animals and subsistence harvesters in the circumarctic. We investigated recent trends (2015-2022) of brucellosis seropositivity in caribou (Rangifer tarandus) and muskoxen (Ovibos moschatus) in the Central Canadian Arctic by using data from community-based wildlife health surveillance programs. The overall sample prevalence of Brucella antibodies was 10.0% (n = 271) in muskoxen and 15.5% (n = 277) in caribou. Sample seroprevalence in muskoxen varied geographically with an increasing trend of exposure on NW Victoria Island (from 0% to 36.8% between 2016 and 2022; Kendall tau = 0.283, p = 0.001). The presence of Brucella suis biovar 4 was confirmed by culture from clinical cases in this area. Our results indicate that Brucella suis biovar 4 continues to circulate in the Central Canadian Arctic in caribou and muskoxen and may be now circulating in muskoxen independently from caribou. These findings highlight the need to better understand the ecology and drivers of brucellosis emergence in Arctic multi-host systems.