Efficacy of a controlled release of rabbit calicivirus disease in southern Victoria

The controlled release of rabbit calicivirus (RCV) was implemented within the Port Phillip Region of Victoria to monitor the regional impact of RCV as a biological agent for the control of rabbits (Oryctolagus cuniculus). Captured rabbits (273) were dosed with 0.5 ml (1500 x LD50) of a rabbit calicivirus suspension and released across nine intensively monitored sites (20 to 30 rabbits per site). These sites were located within 150 km of Melbourne and releases of RCV occurred in November 1996 at one site and in February 1997 at the remaining sites. Prior to release, replicated spotlight counts confirmed high numbers of rabbits (mean = 39, range = 20, 75 rabbits km-1). Moderate to heavy infestations of rabbits (mean = 26, range = 17, 35 rabbits km-1) still existed 6 to 8 weeks post release. At the time of release 64% of 7557 warren entrances (262 warrens) monitored were active and up to 4 weeks later 54% remained active. Rabbit calicivirus spread naturally to all sites 3 months prior to the controlled release. Rabbits inoculated with RCV had pre-existing high levels of immunity to the disease, 38% (range = 10%-50%) of 221 rabbits sampled and released had antibodies to RCV. Twelve months after the release (February 1998), the level of immunity remained relatively high, 50% (range = 40%-69%) of 211 rabbit sera tested had antibodies to RCV. At the time of release myxomatosis was also active at 8 of 9 sites. There was no significant reduction in rabbit numbers or decrease in the proportion of active warren entrances for a 6 to 8 week period after the release of RCV. The controlled release of RCV in February 1997, did not effectively control rabbits in this region of Southern Victoria.

Author McPhee, S.R., Perry, D.R., Roberts, J., Hay, P., Martin, L.M., McCaughan, T.P., Drummond, J.E., Armand, S.M., Muller, J.D. and Bloomfield, T.E.
Date null
Year 1998
Secondary title 11th Australian Vertebrate Pest Conference
Place published Conference Location
Publisher Agriculture Western Australia, Bunbury
Pages 147-152
Notes Notes
Control method Biological Control
Region VIC