Table 1.

Information of samples for PCR detection and strains isolation

Province	Sampling city	Breed	Age (day)	Joint fluid swabsa	Chicken legsa	No. of farm	Sampling time
Guangdong	Yunfu, YangJiang, Heyuan, Zhaoqing, Foshan, Qingyuan, Jiangmen	Three-Yellow, Chaohua, Silky, Qingyuan Ma, Wenchang, Tianlushan, Short footed	29–70	5934	61	1978	2010.10–2014.12
Guangxi	Nanning, Guilin, Hezhou, Yulin	Three-Yellow, Chaohua, Silky, Qingyuan Ma, Short footed	31–75	2004	24	668	2010.09–2014.12
Zhejiang	Quzhou, Huzhou, Jiangshan	Ditto	30–65	1233	24	411	2012.03–2014.12
Jiangsu	Zhengjiang, Suzhou, Nanjing, Yancheng, Suqian, Huaian, Nantong, Lianyungang,	Ditto	28–68	1809	14	603	2012.01–2014.12
Hunan	Hengyang, Changsha	Ditto	30–65	1407	16	469	2013.01–2014.12
Hubei	Wuhan, Jingzhou	Three-Yellow, Chaohua, Silky, Qingyuan Ma, Wenchang, Tianlushan, Short footed	42–58	468	6	156	2013.02–2014.12
Anhui	Hefei, Wuhu, Haozhou, Chuzhou	Ditto	33–71	900	4	300	2013.01–2014.12
Jiangxi	Nanchang, Jian	Ditto	30–60	1110	8	370	2013.04–2014.12
Sichuang	Meishan, Deyang, Chengdu	Ditto	32–66	921	12	307	2011.06–2014.12
Yunnan	Kunming, Dali	Ditto	26–71	504	4	168	2012.04–2014.12
Guizhou	Qingzhen, Guiyang	Ditto	31–56	156	5	52	2011.08–2014.12
Chongqing	Chongqing	Ditto	30–64	297	4	99	2012.03–2014.12
Fujian	Putian, Zhangzhou	Three-Yellow, Chaohua, Silky, Qingyuan Ma, Short footed	30–75	723	21	241	2013.02–2014.12
Shangdong	Taian	Three-Yellow, Tianlushan,	30–52	81	3	27	2013.11–2014.12
Hebei	Cangzhou	Three-Yellow, Silky, Qingyuan Ma	33–61	384	4	128	2011.06–2014.12
Hainan	Haikou, Qionghai	Three-Yellow, Wenchang	45–65	132	4	44	2014.03–2014.12
Total				18,063	215	6021	2010–2014

^aJoint fluid swabs were collected for PCR detection from 2010; ^b Chicken legs were collected for strain isolation between 2013 and 2014