4Hall W V. Porcine reproductive and respiratory syn- drome(PRRS) virus a significant disease of pigs[J].Aust Vet J,2005,83(5) :260-261.
5Francois J P,Danbing K, Dominique K B,et al. Use of tuf Sequences for Genus-Specific PCR Detection and Phylogenetic Analysis of 28 Streptococcal Species[J].Journal of clinical Microbiology, 2004, 42 (8):3686-3695.
