Trypanosoma cruzi infection in Triatoma infestans and high levels of human–vector contact across a rural-to-urban gradient in the Argentine Chaco

Table 3 Risk factors for Trypanosoma cruzi infection in Triatoma infestans collected in domiciles and high-risk peridomestic ecotopes, Avia Terai, Chaco

Predictor	Univariate analyses			Firth-penalized multiple logistic regression (n = 408)
Predictor	Odds ratio	95% CI	P	Odds ratio	95% CI	P
Environment
Urban	1.00	–	–	1.00	–	–
Peri-urban	20.81	2.67–2681.96	< 0.01*	16.60	2.07–2150.73	< 0.01*
Rural	16.10	2.17–2055.80	< 0.01*	13.23	1.73–1699.53	< 0.01*
Stage
Third-fourth nymph	1.00	–	–	1.00	–	–
Fifth-instar nymph	0.67	0.26–1.65	0.38	0.63	0.24–1.65	0.35
Male	0.64	0.23–1.65	0.36	0.64	0.22–1.79	0.40
Female	0.45	0.15–1.26	0.13	0.39	0.12–1.12	0.08
Blood meal on
Dog	1.85	0.77–4.10	0.16	2.80	1.03–7.31	0.04*
Cat	3.89	1.49–9.29	< 0.01*	4.02	1.46–10.39	< 0.01*
Human	2.69	1.29–5.54	< 0.01*	3.15	1.27–8.17	0.01*
Chicken	0.64	0.28–1.35	0.25	1.13	0.43–2.88	0.80
Site bug abundance (triatomines captured per one-person h)
≤ 8	1.00	–	–	–	–	–
9–20	1.34	0.44–4.71	0.62	–	–	–
21–52	0.83	0.27–2.99	0.77	–	–	–
> 52	0.49	0.15–1.76	0.25	–	–	–
Number of dogs and cats per house^a
≤ 3	1.00	–	–	–	–	–
4–5	0.76	0.13–3.50	0.73	–	–	–
6–8	2.21	0.71–7.86	0.17	–	–	–
> 8	9.49	3.49–31.66	< 0.01*	–	–	–
Number of human residents per house^b
≤ 2	1.00	–	–	–	–	–
3	0.57	0.14–1.71	0.34	–	–	–
4–7	0.17	0.03–0.55	< 0.01*	–	–	–
> 7	0.60	0.23–1.44	0.26	–	–	–

ISSN: 1756-3305