[PCR detection of PCV-2 and PRRSV in porcine pleuropneumonia samples].

PCV-2 (Porcine circovirus type-2, PCV-2) and PRRSV (Porcine reproductive and respiratory syndrome virus, PRRSV) were detected by PCR from 253 porcine pleuropneumonia samples and 125 clinically healthy lung samples were collected from different districts of Shandong province. The results showed that 171 samples for PCV-2 and 101 samples for PRRSV were positive. The positive ratio were 67.5% and 40%, respectively. The co-infection number of PCV-2 and PRRSV was 68 in 253 samples, the positive ratio was 26.8%. While in the clinically healthy samples, only 21 samples for PCV-2 and 12 samples for PRRSV were detected positive, the positive ratio were 16.8% and 9.6%, respectively, no co-infection samples were found. Statistical result showed significant difference between positive ratio for PCV-2 and PRRSV in porcine pleuropneumonia samples and that of in clinically healthy samples. The above results demonstrated that there maybe some relationship between the infection of porcine pleuropneumonia and PCV-2 and PRRSV in pigs.

[Analysis on variation of hemagglutinin genes of sixteen H9N2 subtype avian influenza viruses isolated in Shandong area].

In order to explore the genetic mutations of the H9N2 subtype avian influenza viruses isolated in Shandong, sixteen avian influenza virus subtype H9N2 were isolated from different areas of Shandong Province. The complete HA fragments of the viruses were amplified by RT-PCR and the sequences were analyzed on homology and heredity evolution after the cloning and sequencing of the products. The results showed that the amino acid motif of cleavage sites for all the sixteen virus in the HA gene were RSSR decrease GLF, which was consistent with the characterization of the LPAIV. Seven to nine potential glycosylation sites were found during the analysis and the receptor binding sites were relatively conservative except the 198 site. The Leucine(L) at the amino acid position 234 in the HA genes of all isolates indicated the potential of binding with SAalpha,2-6 receptor of mammals. Homology analysis showed that the homology of HA nucleotide and amino acid sequences was 96.3%-99.9% and 97.1%-99.6% for different strains. They belonged to a branch of the A/Duck/Hong Kong/Y280/97 in the phylogenetic tree.