Table 1.

Seroprevalence of Borrelia burgdorferi, determined using ELISA, in 727 horses according to age, gender, breed, and region of sample collection

Group		No. tested	No. positive	Observed prevalence (%)	True prevalence (%)	95% CI*	P-value
Age (yr)	< 5	197	11	5.6	5.9	3.0-10.2	0.075
	5-10	236	4	1.7	1.8	0.6-4.5
	> 10	200	6	3.0	3.2	1.4-6.6
	Unknown	94	17	18.1	19.0	12.0-28.3
Gender	Male	124	4	3.2	3.4	1.2-8.2	0.710
	Female	250	10	4.0	4.2	2.2-7.5
	Castrated	259	7	2.7	2.8	1.3-5.7
	Unknown	94	17	18.1	19.0	12.0-28.3
Breed	Thoroughbred	477	17	3.6	3.8	2.2-5.9	< 0.001
	Korean native pony	109	17	15.6	16.4	10.2-24.9
	Warmblood	61	4	6.6	6.9	2.4-16.7
	Mixed	80	0	0.0	0.0	0-4.7
Region	Northern	211	5	2.4	2.5	1.0-5.6	< 0.001
	Central	179	4	2.2	2.4	0.8-5.7
	Southern	243	12	4.9	5.2	2.9-8.7
	Jeju-do	94	17	18.1	19.0	12.0-28.3
Total		727	38	5.2	5.5	4.0-7.5

^*CI: confidence interval, calculated by Blaker’s method.