Genetic characterisation of Australian strains of porcine circovirus types 1 and 2.
OBJECTIVE
As post-weaning multi-systemic wasting syndrome (PMWS) has not been identified within Australia, to determine if the absence of disease was associated with genetic differences between the strains of porcine circovirus (PCV) present in Australia and those from countries in association with PMWS.


METHODS
Pig tissues were obtained from weaned pigs found dead or presenting with clinical signs of illthrift and also from neonatal pigs with congenital tremors and used as a source of virus DNA for sequence analysis.


METHODS
DNA was extracted from the tissues and PCV detected by polymerase chain reaction (PCR). PCR with PCV type-specific primers was used to amplify the entire genome from selected tissues. The genomes of three strains of PCV1 and seven strains of PCV2 from three Australian states were sequenced and subjected to phylogenetic analysis using standard procedures.


RESULTS
The three Australian PCV1 strains had 98 to 99% nucleotide identity to strains in other countries and the seven Australian PCV2 strains had 94 to 99% identity to PCV2 strains in other countries where PMWS has occurred. Six of the seven Australian PCV2 strains were genetically similar to each other, while the seventh was more distantly related. There were no consistent differences in the predicted amino acid sequence of the Australian strains of PCV2 and strains associated with PMWS in other countries.


CONCLUSIONS
There were no consistent differences between Australian strains of PCV and those that have been associated with PMWS in other countries and it appears likely that other factors are responsible for the absence of PMWS in Australia.
Muhling
J
J
School of Veterinary and Biomedical Sciences, Murdoch University WA 6150, Australia.
Raye
W S
WS
Buddle
J R
JR
Wilcox
G E
GE
D000818:Animals; D001483:Base Sequence; D018173:Circoviridae Infections / Q000662:veterinary* / Q000821:virology; D017925:Circovirus / Q000145:classification* / Q000235:genetics*; D004279:DNA, Viral / Q000032:analysis*; D016679:Genome, Viral; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000662:veterinary; D013552:Swine; D013553:Swine Diseases / Q000821:virology*
D004279:DNA, Viral