Seroprevalence and Risk Factors of Chlamydia abortus Infection in Tibetan Sheep in Gansu Province, Northwest China

Table 3

Seroprevalence of Chlamydia  abortus infection in Tibetan sheep in Gansu, China, determined by indirect haemagglutination (IHA) test.

Biometric data	Category	Antibody titers							Positive numbers	Tested numbers	Prevalence (%)
		1 : 16	1 : 32	1 : 64	1 : 128	1 : 256	1 : 512	1 : 1024
Age (years)	≤1	16	4	0	3	2	0	0	25	335	7.46
	1 < yr ≤ 2	39	12	7	2	2	0	0	62	392	15.82
	2 < yr ≤ 3	19	10	4	2	3	0	0	38	194	19.59
	yr > 3	114	46	23	7	5	2	1	198	811	24.41
Region	Tianzhu County	83	30	21	12	10	0	1	157	962	16.32
	Maqu County	85	35	8	2	1	2	0	133	588	22.62
	Luqu County	20	7	5	0	1	0	0	33	182	18.13
Sex	Male	76	24	9	2	2	1	0	114	530	21.51
	Female	112	48	25	12	10	1	1	209	1202	17.39
Season	Winter	28	10	4	3	2	0	1	48	375	12.80
	Spring	48	20	11	4	6	0	0	89	480	18.54
	Autumn	62	22	8	5	1	0	0	98	479	20.46
	Summer	50	20	11	2	3	2	0	88	398	22.11
	Total	188	72	34	14	12	2	1	323	1732	18.65