From Environmental Predictors to Suitability Mapping: Integrating Factor Analysis and Multivariable Logistic Regression Modelling of Herd-Level Seropositivity for Neospora caninum, Toxoplasma gondii, and Coxiella burnetii in Greek Dairy Cattle Herds

Associations between environmental and demographic predictors and herd-level seropositivity for Neospora caninum, Toxoplasma gondii, and Coxiella burnetii were evaluated using ELISA results from 737 cattle in 42 Greek dairy herds (2018–2019). At the individual level, apparent seropositivity was 24.56% (95% CI: 11.53–37.58) for N. caninum, 15.74% (95% CI: 7.69–23.79) for T. gondii, and 21.17% (95% CI: 14.38–27.95) for C. burnetii. Herd-level seropositivity was 64.29% (95% CI: 49.17–77.01) for N. caninum, 50.00% (95% CI: 35.53–64.47) for T. gondii, and 57.14% (95% CI: 42.21–70.88) for C. burnetii. Factor analyses were used to summarize correlated environmental predictors. Factor scores and additional variables were evaluated in pathogen-specific multivariable logistic models. A temperature-related factor was negatively associated with N. caninum seropositivity (OR = 0.21, 95% CI: 0.07; 0.67, p = 0.008) but positively with T. gondii seropositivity (OR = 170.2; 95% CI: 5.74–5042.8, p = 0.003). A vegetation-related factor was positively associated with seropositivity for T. gondii (OR = 6.25; 95% CI: 1.63–23.97, p = 0.008) and C. burnetii (OR = 3.23; 95% CI: 1.18–8.82, p = 0.022). Elevation was positively associated with T. gondii seropositivity (OR = 1.015; 95% CI: 1.0016–1.029, p = 0.029). A precipitation-related factor was negatively associated with C. burnetii seropositivity (OR = 0.34; 95% CI: 0.13–0.87, p = 0.024). Tetrachoric correlations were −0.786 for N. caninum–T. gondii, −0.688 for N. caninum–C. burnetii, and 0.880 for T. gondii–C. burnetii. Pathogen-specific suitability areas and areas requiring extrapolation were mapped; prevalence and disease risk were not estimated.