Table 3. Risk factors related to B. microti based on univariate analyses.

Variable	Simple size		Babesia microti infection
	cases	constituent ratio(%)	positive rate	χ2	p
altitude(m)
~1500	833	37.79	2.76
1500~2500	456	20.69	5.04	24.466	<0.01
2500~	915	41.52	0.77
gender
male	1059	48.05	2.46	0.022	0.882
female	1145	51.95	2.36
age
adult	1932	87.66	2.69	5.486	0.019
pubertal	272	12.34	0.37
landscape
agricultural	1176	53.36	1.79
forest	920	41.74	3.37		0.043a
residential	108	4.9	0.93

a) Fisher’s exact test