1. Department of Parasitology, Branch of Animal Husbandry and Veterinary of Heilongjiang Academy of Agricultural Sciences, Qiqihar, P.R. China;
2. Northeastern Science Inspection Station, China Ministry of Agriculture Key Laboratory of Animal Pathogen Biology, Northeast Agricultural University, Harbin, P.R. China;
3. College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, P.R. China;
4. Heilongjiang Zhalong National Natural Reserve Administration, Qiqihar, P.R. China