A comprehensive presentation on feral rabbits, there effect on the Australian Landscape and the introduction of the biological control RHDV1 K5

1. Marc Widmer successfully defends WA
from European wasp attack.
Supporting your success
Rabbits: destructive pests of agriculture
and the environment.
Susan Campbell

2. • 1859 – successful introduction of 24 rabbits in Victoria
• ~1930 – colonisation of 2/3rd country by ~10 billion rabbits
A brief history70years

4. • 1859 – successful introduction of 24 rabbits in Victoria
• ~1930 – colonisation of 2/3rd country by ~10 billion rabbits
• 1950 – release of myoxa virus = 99.8% reduction
• 1990 – population recovery to ~600 million rabbits
• 1995/96 – ‘release’ of rabbit haemorrhagic disease virus (RHDV)
• Average 67% reduction in arid areas
• Average 27% reduction in higher rainfall areas (highly variable)
• ~2010 – rabbit numbers nationally trending upwards
A brief history70years

5. Inevitable recovery?
Why do rabbits always ‘bounce back’?
Some rabbits survive exposure to virus:
• Individual variation
• Genetic immunity in populations
evolves over time
RHDV specific immunity:
• Maternal antibodies up to ~6-8weeks
(variable)
• Innate resistance in very young
rabbits
• Benign virus

6. Breed like rabbits
Why do rabbits always ‘bounce back’?
• 2 200 40, 000!
• Sexually mature at 3-4 months
• Gestation lasts ~31 days
• 2-12 kittens per litter
• 4-7 litters per year
• Female can mate within hours of
giving birth
• One doe can produce 50-60 offspring
per season
• Rabbits’ success has been aided by
the use of warrens which provide
shelter in hot / dry habitats.
2 years 2 years

7. Rabbit impacts
Rabbits are Australia’s most destructive agriculture pest.
Competition with, and land degradation from, rabbits threatens
over 300 native plant and animal species.
Environmental
• Even very low densities of rabbits (<1
rabbit per hectare) can prevent the
regeneration of perennial plant species
• 304 listed native species threatened by
rabbits
• Rabbits are food for feral predators
Agricultural
• Rabbits are Australia’s most costly
agricultural pest, causing over $200
million in damage per year
Social
• Rabbits threaten places, plants and
animals that people value

8. • 1859 – successful introduction of 24 rabbits in Victoria
• ~1930 – colonisation of 2/3rd country by ~10 billion rabbits
• 1950 – release of myoxa virus = 99.8% reduction
• 1990 – population recovery to ~600 million rabbits
• 1995/96 – ‘release’ of rabbit haemorrhagic disease virus (RHDV)
• Average 67% reduction in arid areas
• Average 27% reduction in higher rainfall areas (highly variable)
• ~2010 – rabbit numbers nationally trending upwards
• 2017 – RHDV Boost
A brief history70years

9. The need for new biocontrol1945
1948
1951
1954
1957
1960
1963
1966
1969
1972
1975
1978
1981
1984
1987
1990
1993
1996
1999
2002
2005
2008
0
20
40
60
80
100
120
140
Rabbitabundanceindex
Benefit from
myxomatosis
Myxomatosis
RHD
Benefit
from RHD
2011
2014
2017
2020
2023
2026
2029
RHD-Boost
RHD-Accelerator
Bioprospecting
Rabbit impact threshold
Rabbit numbers (solid blue line) continue to recover post biocontrol

10. RHDV1-K5: a naturally occurring variant from Korea
• 37 naturally occurring strains imported and tested.
• RHDV1-K5
• Overcomes antibodies to RCV-A1 (benign strain)
• The existing commercial vaccine is effective against RHDV1
• Requires 30 times less virus compared to original strain to infect wild rabbits
• RHDV1-K5 infection results in increased (and faster, ~24-36hrs) mortality
• RHDV suspension is a Restricted Chemical Product
• Authorisation training required in WA.
• RHDV1 K5 is now available as a commercial product –
• Contact DAFWA for details on training and access.
Selecting a new strain of RHDV

11. RHDV1-K5: Directions of use
• May be administered to susceptible rabbits either by direct injection or by means
of infected carrot or oat feed.
• RHDV1-K5 will not infect any other animal. Animals that may consume a rabbit
that is sick or deceased from RHDV1-K5 will not be affected by the virus.
Directions for use

12. RHDV1-K5: Infection pathways
• Bush and blow flies are known vectors for RHD virus and will spread virus over
large distances, assisted by prevailing wind streams.
• Flies deposit virus as fly-spots on pasture, which is then consumed by rabbits.
• Flies can also spread the virus directly to rabbits by landing on individuals.
• Virus can be spread easily by direct contact between rabbits
• Biting insects such as mosquitoes and
fleas can also spread infection.
Spread

13. Supporting your success
RHDV1-K5: When do outbreaks occur?
• Outbreaks are more likely when vector (fly / flea / mosquito) activity is high.
• Avoid applying when there is a high proportion of rabbits <12weeks old or
pregnant does.
• Best practice time for deliberate release is late Spring / Autumn (adequate
vector activity, lower proportion of kittens present and lower availability of
alternate food sources)
Timing

14. The national release of RHDV1 K5
• Nationally – 42% reduction in
observed rabbit numbers
• Most states ~36% reduction in
observed rabbit numbers
RHDV1 K5 released at close to 600 sites in March 2017.
• 579 community managed release sites
• 104 (<20%) supplied pre-release count data
• 52 (<10%) supplied post-release count data

15. West Australian release sites
Out of 163 initial expressions of interest, 106 community releases in WA

16. RHDV2 in Australia
• In May 2015, RHDV2 virus detected in
wild rabbits in Canberra, and has
since spread across the majority of
the country.
• RHDV2 is present in Europe, it is not
known how it arrived into Australia.
• RHDV2 causes the same mode of
death as RHDV1, however they are
two separate viruses.
• The currently available vaccine is not
fully protective against RHDV2.
RHDV rabbit carcass: Brian Lukin, NSW DPI

17. Control – Maximising benefits
Follow up with conventional control
• A significant opportunity to really supress rabbit numbers was missed after the
1995-6 release of the original RHDV1-czech strain due to a lack of follow up
control.
• To promote long-term area freedom from rabbits, conventional control including
baiting, harbour destruction (including warren ripping) and other methods are
required immediately after a successful outbreak of RHDV to ‘mop up’
survivors and remove the critical resource (warrens / harbour).
INTEGRATED CONTROL
Full benefits of biological control are only
achieved where poisoning, warren ripping and
fumigation are used to remove remnant rabbits
and their harbour (warrens)

18. Conventional control options
• Baiting
• Warren ripping
• Fumigation
• Shooting
• Exclusion fencing

19. Baiting
• Baiting – permit required (contact DAFWA)
Two types of toxin available for rabbit control
- 1080 (Sodium fluroacetate)
- Pindone
WORK TOGETHER
Can achieve high control rate
Cover large areas
Selective - Bait stations
Non Targets-1080 Tolerance
Choice of toxin to suit situation
Secondary poisoning
Pindone

20. Protection of fauna
• Rabbits provide a food source for foxes, feral
cats, dingoes / wild dogs and birds of prey.
• Decline of rabbit numbers from any cause may
result in increased predation on critical
populations of vulnerable or endangered fauna,
at least in the short term.
• Be aware of populations of native animals before
undertaking rabbit control and seek advice from
DPaW.
• Complimentary predator control measures
should be implemented if necessary.
• Evidence shows that in the long term, fewer
rabbits present in an area tends to result in fewer
predators.
Integrated Pest Management

21. Thank you
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Important disclaimer
The Chief Executive Officer of the Department of Agriculture and Food and the State of
Western Australia accept no liability whatsoever by reason of negligence or otherwise
arising from the use or release of this information or any part of it.
Copyright © Western Australian Agriculture Authority, 2016
Supporting your success