Table 1.

Bivariate and multivariate analysis of factors associated to Theileria equi infection in horses, by real-time PCR, according to animal characteristics, locality, zootechnical and sanitary management, contact with cattle, animals activity, breeding systems, ticks infestation in Petropolis and Seropedica municipalities, Rio de Janeiro, Brazil

Characteristic of the animals and management	Real-time PCR		Bivariate		Multivariate
	Number of animals sampled	Positives (%)	χ 2	P	P	OR	CI 95 %
Gender
Male	194	80.00	0.003	0.956	−	−	−
Female	120	80.93
Age
≤2 years	42	78.57	0.020	0.887	−	−	−
>2 years	272	80.88
Racial definition
Mixed breed	140	83.57	0.444	0.505	−	−	−
Defined breed	174	78.16
Locality
Petropolis (>400 m)	173	72.25	15.870	0.000	–a
Seropedica (<400 m)	141	90.78			0.39	−	0.6–3.2
Zootechnical and sanitary management
Satisfactory	150	66.67	33.803	0.000b	−	−	−
Unsatisfactory	164	93.29
Contact with cattle
No	218	77.06	4.900	0.027	–a
Yes	96	88.54			0.48	−	0.2–1.8
Activity
Sport/exposition	118	61.02	46.200	0.000	–a
Work/walk	127	92.13			0.00	5.75	2.2–14.4
Reproduction	69	92.75			0.02	3.85	1.3–11.5
Breeding system
Confined	19	78.95	−	0.970c	−	−	−
Extensive/semi-extensive	295	78.64
Ticks infestation
No	153	67.97	28.713	0.000	–a
Yes	161	92.55			0.03	2.63	1.1–6.2
Animals’ origin
Inside property	98	84.69	1.186	0.276	−	−	−
Outside property	216	78.70

χ ² value of chi-square test, P p value, OR odds ratio, CI confidence interval

^aCategory reference

^bRemoved from the multivariate analysis due to collinearity verified by Spearman test

^cFisher’s exact test