Long-term survival of New Zealand rabbit haemorrhagic disease virus RNA in wild rabbits, revealed by RT-PCR and phylogenetic analysis.
Because Rabbit haemorrhagic disease virus (RHDV) is highly pathogenic for rabbits, farmers illegally introduced it as a bio-control agent onto New Zealand farms in 1997. The virus was dispersed rapidly, initially causing high fatality rates in rabbits. Nevertheless, many survived and these surviving rabbits have been investigated for evidence of infection by RHDV. Livers from healthy rabbits contained RHDV-specific RNA, as shown by nested RT-PCR sequencing. The sequences of the viral capsids were related closely to the released Czech strain of RHDV, although the sequence from one rabbit was related most closely to a Spanish strain of RHDV. Phylogenetic analysis of the capsid sequences of 38 samples implied that there have been at least two introductions of the Czech virus into New Zealand, probably corresponding firstly to the original illegal introduction by farmers and secondly to the introduction of the same virus under governmental control. Genomic length sequence of two samples was obtained, suggesting that they may have retained the potential to be infectious, although this has not yet been demonstrated. The detection of genomic-length RNA in the liver of healthy rabbits suggests that even though a highly virulent virus was introduced into New Zealand, it rapidly established persistent or latent infections in a proportion of rabbits. This might account for their ability to survive in the face of virulent released virus. Moreover, the co-circulation of other strains of RHDV in the same rabbit population, such as the Spanish strain, might also impact on their susceptibility to the bio-control agent.
Forrester
N L
NL
Centre for Ecology and Hydrology (formerly Institute of Virology), Mansfield Road, Oxford OX1 3SR, UK.
Boag
B
B
Birch Brae, Knapp, Perth and Kinross PH14 9SW, UK.
Moss
S R
SR
Centre for Ecology and Hydrology (formerly Institute of Virology), Mansfield Road, Oxford OX1 3SR, UK.
Turner
S L
SL
Centre for Ecology and Hydrology (formerly Institute of Virology), Mansfield Road, Oxford OX1 3SR, UK.
Trout
R C
RC
Rabbit-Wise, Holtside, Batts Corner, Dockenfield, Surrey GU10 4EX, UK.
White
P J
PJ
Institute of Biological Science, University of Stirling, Stirling FK9 4LA, UK.
Hudson
P J
PJ
Institute of Biological Science, University of Stirling, Stirling FK9 4LA, UK.
Gould
E A
EA
Centre for Ecology and Hydrology (formerly Institute of Virology), Mansfield Road, Oxford OX1 3SR, UK.
D000818:Animals; D016679:Genome, Viral; D017929:Hemorrhagic Disease Virus, Rabbit / Q000145:classification / Q000235:genetics / Q000502:physiology*; D008099:Liver / Q000821:virology; D010802:Phylogeny; D012367:RNA, Viral / Q000032:analysis* / Q000737:chemistry; D011817:Rabbits; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014779:Virus Replication
D012367:RNA, Viral