Table 3 Fixed effects in generalized linear mixed models to determine potential risk factors for Toxoplasma gondii-seropositivity in wild felids in human care. Data were analyzed by bivariable generalized linear mixed modelling including “Age” (years) as effect modifier and “Zoo” as random effects variable in modelling T. gondii-seropositivity. The Akaike information criterion (AIC) was used to characterize the relative model quality

Individual risk factors

1 (357.4)

(Intercept)

0.523 (0.33–0.83)

− 2.718

0.0066**

Age

1.219 (1.21–1.23)

80.86

< 0.001***

2 (354.8)

(Intercept)

0.401 (0.19–0.86)

− 2.363

0.0181*

Age

1.218 (1.12–1.32)

4.640

< 0.001***

Sex: female (ref.)

Sex: male

1.779 (1.01–3.15)

1.976

0.0482*

Food-related risk factors

3 (300.6)

(Intercept)

1.309 (0.46–3.76)

0.500

0.6171

Age

1.224 (1.12–1.34)

4.278

< 0.001***

Mice: fresh (ref.)

Mice: fresh/frozen

0.240 (0.06–0.99)

− 1.975

0.0482*

Mice: frozen

0.308 (0.08–1.13)

− 1.776

0.0757

Mice: no

0.407 (0.08–2.00)

− 1.109

0.2675

4 (301.4)

(Intercept)

1.474 (0.40–5.44)

0.582

0.5609

Age

1.231 (1.12–1.35)

4.325

< 0.001***

Rodents: fresh (ref.)

Rodents: fresh/frozen

0.277 (0.06–1.32)

− 1.614

0.1066

Rodents: frozen

0.250 (0.05–1.19)

− 1.746

0.0809

Rodents: no

0.445 (0.05–4.22)

− 0.705

0.4807

5 (296.6)

(Intercept)

0.986 (0.25–3.97)

− 0.019

0.9845

Age

1.232 (1.12–1.35)

4.327

< 0.001***

Ruminants: fresh (ref.)

Ruminants: fresh/frozen

0.792 (0.14–4.60)

− 0.260

0.7947

Ruminants: frozen

0.158 (0.03–0.85)

− 2.146

0.0319*

Ruminants: no

0.763 (0.17–3.43)

− 0.353

0.7242

6 (296.4)

(Intercept)

1.157 (0.26–5.10)

0.192

0.8478

Age

1.232 (1.12–1.35)

4.331

< 0.001***

Cattle: fresh (ref.)

Cattle: fresh/frozen

0.675 (0.11–4.23)

− 0.420

0.6744

Cattle: frozen

0.135 (0.02–0.80)

− 2.210

0.0271*

Cattle: no

0.629 (0.13–3.07)

− 0.573

0.5667

7 (301.9)

(Intercept)

1.725 (0.36–8.17)

0.686

0.4925

Age

1.222 (1.11–1.34)

4.195

< 0.001***

Fowl: fresh (ref.)

Fowl: fresh/frozen

0.354 (0.07–1.92)

− 1.204

0.2285

Fowl: frozen

0.221 (0.04–1.13)

− 1.817

0.0693

Fowl: no

0.371 (0.02–5.62)

− 0.715

0.4746

Breeding and housing-related risk factors

8 (321.4)

(Intercept)

0.188 (0.06–0.59)

− 2.859

0.0043**

Age

1.229 (1.12–1.34)

4.526

< 0.001***

Litters within 1 year-Null (ref.)

Few litters (1–2) within 1 year

3.767 (1.12–12.7)

2.365

0.0180*

Many litters (≥ 3) within 1 year

5.097 (1.32–19.7)

2.138

0.0325*

9 (324.4)

(Intercept)

0.224 (0.06–0.81)

− 2.279

0.0227*

Age

1.222 (1.12–1.34)

4.392

< 0.001***

Litters within 5 years: null (ref.)

Few litters within 5 years, 1–9

2.311 (0.62–8.67)

2.115

0.0345*

Many litters within 5 years, ≥ 10

4.191 (1.11–15.8)

1.242

0.2143

10 (297.9)

(Intercept)

0.662 (0.30–1.45)

− 1.031

0.3026

Age

1.236 (1.12–1.36)

4.364

< 0.001***

New World monkeys close by: no (ref.)

New World monkeys close by: yes

0.309 (0.08–1.16)

− 1.738

0.0822

11 (298.4)

(Intercept)

1.568 (0.41–6.06)

0.653

0.5140

Age

1.216 (1.11–1.33)

4.196

< 0.001***

Outdoor housing fenced in on all sides: no (ref.)

Outdoor housing fenced in on all sides: yes

0.297 (0.08–1.15)

− 1.759

0.0785

12 (291.5)

(Intercept)

2.169 (0.61–7.68)

1.177

0.2393

Age

1.208 (1.10–1.32)

4.247

< 0.001***

Mesh size > 5 cm (ref.)

Mesh size < 2 cm

0.511 (0.10–2.71)

− 0.969

0.3326

Mesh size 2–5 cm

0.204 (0.05–0.79)

− 2.416

0.0157*

Hygiene related risk factors

13 (295.1)

(Intercept)

0.862 (0.40–1.85)

− 0.379

0.7044

Age

1.225 (1.12–1.34)

4.347

< 0.001***

Wearing gloves: no (ref.)

Wearing gloves: yes

0.286 (0.10–0.79)

− 2.429

0.0151*

General health related risk factors

14 (248.5)

(Intercept)

0.204 (0.07–0.61)

− 2.829

0.0047**

Age

1.256 (1.13–1.40)

4.196

< 0.001***

Rabies vaccination: no (ref.)

Rabies vaccination: yes

4.910 (1.35–17.8)

2.417

0.01563*

15 (175.8)

(Intercept)

0.048 (0.00–0.68)

− 2.243

0.024903*

Age

1.307 (1.12–1.52)

3.417

0.000633***

Deworming interval (months)

1.449 (0.98–2.14)

1.876

0.060723