The seroprevalence and risk factors for exposure to Neospora caninum and Neospora hughesi in Ontario broodmares

The seroprevalence and risk factors for exposure to Neospora caninum and Neospora hughesi in broodmares in Ontario were investigated. Sixty of the 219 (27.4%) study broodmares were seropositive for N. caninum and 65/ 219 (29.7%) for N. hughesi with cut-offs of >= 1:40 and >= 1:160, respectively . Thirty-one of 63 participating farms (49.2%) had at least 1 broodmare seropositive for N. caninum . Thirty-three of the 63 (52.4%) participating farms had at least 1 broodmare positive for N. hughesi . Risk factors for N. caninum included presence of farm dogs (OR = 6.70; 95% CI = 2.14 -20.97; p = 0.001), and high stocking density (OR = 2.83; 95% CI = 1.27 -6.30; p = 0.011). Presence of livestock, excluding cattle, was associated with reduced risk of exposure (OR = 0.17; 95% CI = 0.06 -0.53; p = 0.002). The only risk factor for exposure to N. hughesi was feeding hay on the ground in the paddock (OR = 4.31; 95% CI = 1.65 -11.22; p = 0.003). This study demonstrated widespread exposure to Neospora spp. in broodmares in Ontario.