Changes in immunity to rabbit haemorrhagic disease virus, and in abundance and rates of increase of wild rabbits in Mackenzie Basin, New Zealand
John P. Parkes A C , Brent Glentworth B and Graham Sullivan B
A Landcare Research, PO Box 40, Lincoln 7640, New Zealand.
B Environment Canterbury, PO Box 550, Timaru 7940, New Zealand.
C Corresponding author. Email: email@example.com
Wildlife Research 35(8) 775-779 http://dx.doi.org/10.1071/WR08008
Submitted: 21 January 2008 Accepted: 27 August 2008 Published: 16 December 2008
The evolutionary race between diseases and their hosts may lead to attenuation of the disease agent, increasing resistance in the host, or both. This is an undesirable outcome when the disease is being used as a biocontrol agent but a desired outcome when the host is valued by people. Introduced wild rabbits Oryctolagus cuniculus are a pest to agriculture and biodiversity values in New Zealand’s grasslands, particularly on the drier eastern sides of both islands. The costs to manage them using conventional control could not be sustained by landowners who since the 1980s have proposed the introduction of the viral biocontrol agents myxomatosis and then rabbit haemorrhagic disease virus (RHDV). Myxomatosis failed to establish but RHDV did establish and spread following its illegal introduction in 1997. However, since 1997, rabbit haemorrhagic disease (RHD) has become less effective for biocontrol of rabbits in New Zealand. Three lines of evidence from our four study sites in the Mackenzie Basin support this claim. First, the proportion of rabbits of all ages with antibodies to RHDV has increased in samples of rabbits shot each year since 1997. Taken alone this may simply reflect an accumulation in cross-sectional samples of seropositive older rabbits that have been exposed to infection but survived successive epizootics. Second, the proportion of young rabbits, sampled at an age when they have been exposed to a single epizootic event, that have antibodies to RHDV has also increased since 1997. This is strong evidence that something has changed in the rabbit–virus interaction. The cause of this effect remains unknown but is reflected in the third line of evidence, that the abundance of rabbits as indexed by standardised spotlight counts has increased since 1997. The rate of increase has, however, been much slower than that seen in the same populations as they recovered from conventional control before the arrival of RHD. Thus, we conclude that RHD is still an effective biocontrol but its efficacy is waning.
B. I. P.
A. C. G.
R. A. S.
Can insects transmit rabbit haemorrhagic disease virus?
Proceedings of the New Zealand Plant Protection Conference
Large shifts in pathogen virulence relate to host population structure.
Assessing growth rates of European rabbit populations using spotlight transects.
The Journal of Wildlife Management
Antigenicity of the rabbit hemorrhagic disease virus studied by its reactivity with monoclonal antibodies.
Rabbit haemorrhagic disease and the biological control of wild rabbits, Oryctolagus cuniculus, in Australia and New Zealand.
Use of ELISAs in field studies of rabbit haemorrhagic disease (RHD) in Australia.
Epidemiology and Infection
Co-evolution of wild rabbits (Oryctolagus cuniculus) and RHDV: resistance and virulence.
Proceedings of the Australasian Vertebrate Pest Conference
(1965). ‘Myxamatosis.’ (Cambridge University Press: London.)
Reproductive biology of rabbits, Oryctolagus cuniculus (L.), in central Otago, New Zealand.
New Zealand Journal of Ecology
On rate of increase (r): patterns of variation in Australian mammals and the implications for wildlife management.
Journal of Applied Ecology
Prolonged decline in the abundance of wild European rabbits Oryctolagus cuniculus and high immunity level over three years following the arrival of rabbit haemorrhagic disease.
Wild rabbit restocking for predator conservation in Spain.
Hepatitis of viral origin in Leporidae: introduction and aetiological hypotheses.
Revue Scientifique et Technique. Office International des Epizooties
Molecular epidemiology of rabbit haemorrhagic disease virus.
The Journal of General Virology
(1994). ‘Rabbit Haemorrhagic Disease: Issues in Assessment for Biological Control.’ (Bureau of Resource Sciences: Canberra.)
Determination of age of wild rabbits in Australia.
The Journal of Wildlife Management
(2005). European rabbit. In ‘The Handbook of New Zealand Mammals’. (Ed. C. M. King.). pp. 131–150. (Oxford University Press: Melbourne.)
M. X. J.
Serology of rabbit haemorrhagic disease virus in wild rabbits before and after release of the virus in New Zealand.
Consequences of successful biocontrol. What do we get for fewer rabbits?
Primary Industry Management
Has rabbit haemorrhagic disease worked in New Zealand?
Proceedings of the New Zealand Society of Animal Production
Epidemiology of rabbit haemorrhagic disease (RHD) in the South Island, New Zealand, 1997–2001.
(2004). Effects of predation and rabbit haemorrhagic disease on rabbit population dynamics in New Zealand. PhD Thesis, Lincoln University, New Zealand.
P. T. M.
Statistical models for the effect of age and maternal antibodies on the development of rabbit haemorrhagic disease in Australian wild rabbits.
Binding of rabbit hemorrhagic disease virus to antigens of the ABH histo-blood group family.
Journal of Virology
A. R. E.
(1995). Serengeti past and present. In ‘Serengeti II. Dynamics, Management and Conservation of an Ecosystem’. (Eds A. R. E. Sinclair and P. Arcese.) pp. 3–30. (University of Chicago Press: Chicago, IL.)
Rabbit calicivirus disease now established in New Zealand.
Seroepidemiology of rabbit haemorrhagic disease (RHD) in wild rabbits (Oryctolagus cuniculus) in the United Kingdom.
Journal of Zoology
First epizootic of rabbit hemorrhagic disease in free living populations of Oryctolagus cuniculus at Doñana National Park, Spain.
Journal of Wildlife Diseases
Viral haemorrhagic disease in rabbits: a review.
Veterinary Research Communications