Serologic and molecular survey for major viral pathogens in grazing hybrid wild boars in Northeast China oleh Huan-cheng GUO, Zhao-wen REN, Mei-ming DING, Wan-jun XIAO, Peng PENG, Biao HE, Ye FENG, Yan LIU, Xing-yu LI, Jian-qiu CAI, Bi-kai ZHANG, Qing-hua LUO, Chang-chun TU