Population and demographic patterns of rabbits (Oryctolagus cuniculus) at Roxby Downs in arid South Australia and the influence of rabbit haemorrhagic disease

1998 ◽  
Vol 25 (6) ◽  
pp. 655 ◽  
Author(s):  
Zoë Bowen ◽  
John Read

Rabbit populations and demography were surveyed at Roxby Downs in arid South Australia from 1989 to 1997. Rabbit numbers typically peaked in late summer following breeding from late winter to early summer. After initial declines attributable to burrow flooding and increased populations of virus vectors, rabbit numbers increased by approximately 400% after significant rains. Introductions of Spanish rabbit flea, a vector of Myxoma virus, did not influence rabbit numbers but rabbit haemorrhagic disease (RHD) had a dramatic and sustained influence on rabbit numbers. The optimum times for release of RHD are discussed.


2009 ◽  
Vol 31 (1) ◽  
pp. 65 ◽  
Author(s):  
David E. Peacock ◽  
Ron G. Sinclair

A population of European rabbits (Oryctolagus cuniculus) has been monitored since November 1996 through mark–recapture as part of a longitudinal epidemiological study into two Australian rabbit biocontrol agents, rabbit haemorrhagic disease (RHD) and myxomatosis. A female rabbit, first captured as a subadult in late November 1999, was recaptured 18 times before its final capture at the end of February 2007. The longevity of this rabbit, being from its calculated birth date to the date it was last captured, was 7.6 years. A review of the literature indicates this to be the longest lifespan recorded for a European rabbit in the wild.



2020 ◽  
Vol 8 (1) ◽  
pp. e001002 ◽  
Author(s):  
Carina Luisa Carvalho ◽  
Fábio Alexandre Abade dos Santos ◽  
Teresa Fagulha ◽  
Paulo Carvalho ◽  
Paula Mendonça ◽  
...  

Myxoma virus (MYXV) and rabbit haemorrhagic disease virus 2 (RHDV2) are two major pathogens that affect the European rabbit (Oryctolagus cuniculus). Between August 2017 and August 2019, 1166 wild rabbits (971 legally hunted and 195 found dead) were tested by PCR-based methods for MYXV and RHDV2 within the scope of an ongoing surveillance programme on wild leporids in Portugal. Despite never having been reported before and being considered a rare event, coinfection by RHDV2 and MYXV was detected in one juvenile wild rabbit found dead in the Évora district located in Alentejo. The relative frequency of coinfection in the group of diseased rabbits (found dead in the field) was 0.52 per cent (1/195). The positivity percentage of each single virus was much higher, namely, 14.36 per cent (28/195) for MYXV and 55.38 per cent (108/195) for RHDV2, within the 2 years of sample collection considered.



Vaccines ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 441 ◽  
Author(s):  
Sylvia Reemers ◽  
Leon Peeters ◽  
Joyce van Schijndel ◽  
Beth Bruton ◽  
David Sutton ◽  
...  

Myxoma virus (MV) and rabbit haemorrhagic disease virus (RHDV) are the major causes of lethal viral diseases in the European rabbit. In 2010, a new RHDV genotype (RHDV2) emerged in the field that had limited cross-protection with the classical RHDV (RHDV1). For optimal protection of rabbits and preventing spread of disease, a vaccine providing protection against all three key viruses would be ideal. Therefore, a novel trivalent myxoma vectored RHDV vaccine (Nobivac Myxo-RHD PLUS) was developed similar to the existing bivalent myxoma vectored RHDV vaccine Nobivac Myxo-RHD. The new vaccine contains the Myxo-RHDV1 strain already included in Nobivac Myxo-RHD and a similarly produced Myxo-RHDV2 strain. This paper describes several key safety and efficacy studies conducted for European licensing purposes. Nobivac Myxo-RHD PLUS showed to be safe for use in rabbits from five weeks of age onwards, including pregnant rabbits, and did not spread from vaccinated rabbits to in-contact controls. Furthermore, protection to RHDV1 and RHDV2 was demonstrated by challenge, while the serological response to MV was similar to that after vaccination with Nobivac Myxo-RHD. Therefore, routine vaccination with Nobivac Myxo-RHD PLUS can prevent the kept rabbit population from these major viral diseases.



2006 ◽  
Vol 33 (7) ◽  
pp. 549 ◽  
Author(s):  
D. Berman ◽  
P. J. Kerr ◽  
R. Stagg ◽  
B. H. van Leeuwen ◽  
T. Gonzalez

Release of virulent myxoma virus has been a key component of rabbit-control operations in Queensland, Australia, since the 1960s but its use rests on anecdotal reports. During a routine operation to release virulent myxoma virus we found no evidence to support the continued regular use of the technique in south-west Queensland. Radio-tagged rabbits inoculated with virulent myxoma virus contracted the disease but failed to pass enough virus to other rabbits to spread the disease. Rabbits with clinical signs of myxomatosis that were shot were infected with field strain derived from the original laboratory strain released in 1950 rather than the virulent strain that has been released annually. There was no change in rabbit survival or abundance caused by the release. Nevertheless, the release of virulent virus may be useful against isolated pockets of rabbits mainly because field strains are less likely to be present. Such pockets are more common now that rabbit haemorrhagic disease virus is established in Queensland.



1997 ◽  
Vol 31 (1) ◽  
pp. 33-44 ◽  
Author(s):  
David Chasey

A new, widespread and important disease of rabbits, rabbit haemorrhagic disease (RHD), is concisely reviewed and discussed. RHD is an acute, infectious condition of adult rabbits and morbidity and mortality, after a relatively short incubation period, can be very high. The disease appears typically as a necrotizing hepatitis with associated haemorrhaging, and death occurs as a result of generalized organ dysfunction. RHD is caused by a calicivirus, antigenically related to a similar virus found in brown hares but distinct from other known caliciviruses, and is spread to susceptible rabbits by a number of routes and vectors. The disease is easily identified and can be effectively controlled in commercial and domestic rabbit populations by slaughter and vaccination regimes. The occurrence of pre-existing cross-reacting antibody in a proportion of rabbits unchallenged by the disease implies the presence of non-pathogenic strains of the virus. This antibody protects against disease on subsequent exposure to RHD. Uniquely, pre-existing antibody does not occur in rabbits in Australia where, after accidental release, the virus is currently spreading rapidly.



1978 ◽  
Vol 81 (2) ◽  
pp. 239-243 ◽  
Author(s):  
Rosamond C. H. Shepherd ◽  
J. W. Edmonds ◽  
I. F. Nolan ◽  
A. Gocs

SummarySharp reductions in the wild rabbit (Oryctolagus cuniculus (L.)) population in the Mallee are associated with annual myxomatosis epizootics. The extent to which the population reductionsare the direct result of the epizootics varies with time of epizootic occurrence. All grazing animals in the Mallee are under nutritional stress each summer and autumn. When the epizootic occurs during the early summer heavy losses occur in a previously healthy population. Similar losses which occur in the late summer and autumn are the result of a nutritional stress – epizootic complex. The end result in each case is a population reduction of about 80%.This reduction occurs in a population which is the most resistant to myxomatosis known in Victoria and in association with epizooties caused by field strains of myxoma virus of moderate virulence only.The earlier summer epizootics are of considerable economic importance because they sharply reduce the pressure on the limited food available for other grazing animals.



2004 ◽  
Vol 31 (4) ◽  
pp. 415 ◽  
Author(s):  
B. D. Cooke ◽  
J.-L. Chapuis ◽  
V. Magnet ◽  
A. Lucas ◽  
J. Kovaliski

Rabbits have caused enormous damage to the vegetation on seven islands in the sub-Antarctic Kerguelen archipelago, including the main island, Grande Terre. Rabbit sera collected during 2001–02 were tested for antibodies against myxoma virus and rabbit haemorrhagic disease virus with a view to considering the wider use of these viruses to control rabbits. The results confirmed work done 15–20 years earlier that suggested that myxoma virus has not spread across all parts of Grande Terre and occurs at low prevalence among rabbits. By contrast, on Ile du Cimetière, where European rabbit fleas were introduced in 1987–88, the prevalence of myxoma antibodies is high and the rabbit population is relatively low, supporting the idea that the fleas are effective vectors of myxoma virus. Consequently, there should be benefits in releasing fleas on Grand Terre to enhance disease transmission. Reactivity of some rabbit sera in RHD-specific ELISAs suggested that a virus similar to RHDV may be present at low prevalence on Grande Terre but most rabbits are likely to be susceptible and this virus could be considered for use as a future biological control agent.



2004 ◽  
Vol 31 (6) ◽  
pp. 651
Author(s):  
G. Story ◽  
J. Scanlan ◽  
R. Palmer ◽  
D. Berman

Rabbit haemorrhagic disease virus (RHDV) escaped from quarantine facilities on Wardang Island in September 1995 and spread through South Australia to Queensland by December 1995. To determine the impact of this biological control agent on wild rabbit populations in Queensland, shot sample and spotlight count data were collected at six sites. RHDV spread across Queensland from the south-west to the east at a rate of at least 91 km month–1 between October 1995 and October 1996. The initial impact on rabbit density appeared highly variable, with an increase of 81% (255 ± 79 (s.e.) to 385 ± 73 rabbits km–2) at one site and a decrease of 83% (129 ± 27 to 22 ± 18 rabbits km–2) at another during the first outbreak. However, after 30 months of RHDV activity, counts were at least 90% below counts conducted before RHDV arrived. Using a population model to account for environmental conditions, the mean suppression of rabbit density caused by rabbit haemorrhagic disease (RHD) was estimated to be 74% (ranging from 43% to 94% between sites). No outbreaks were observed when the density of susceptible rabbits was lower than 12 km–2. Where rabbit density remains low for long periods RHDV may not persist. This is perhaps most likely to occur in the isolated populations towards the northern edge of the range of rabbits in Australia. RHDV may have to be reintroduced into these populations. Further south in areas more suitable for rabbits, RHDV is more likely to persist, resulting in a high density of immune rabbits. In such areas conventional control techniques may be more important to enhance the influence of RHD.



2019 ◽  
Vol 237 ◽  
pp. 108361
Author(s):  
L. Camacho-Sillero ◽  
J. Caballero-Gómez ◽  
F. Gómez-Guillamón ◽  
A. Martínez-Padilla ◽  
M. Agüero ◽  
...  


2017 ◽  
Vol 44 (7) ◽  
pp. 582 ◽  
Author(s):  
Scott Jennings ◽  
Gregory Mutze

Context Contact rates are a key determinant of disease transmission. Territorial behaviour has generally been considered to limit contact between European rabbits occupying different warrens, particularly during the breeding season. Aims We investigated warren use by subadult rabbits during a period of low population density to determine their potential role in transmission of rabbit haemorrhagic disease and myxomatosis. Methods Subadult rabbits were radio-collared in late summer and relocated twice-weekly for 25 weeks, during which time they grew to adult size and breeding commenced. Key results Rabbits of both sexes used an average of four warrens each on a regular basis, even after older rabbits had commenced breeding. Warrens used by individual rabbits formed a continuously overlapping, irregular array. Subadult rabbits did not belong to separate social groups that utilised separate groups of warrens. Conclusions Subadult or young adult rabbits did not display the same territorial warren fidelity that had been previously described for rabbits. They have potential to carry pathogens between warrens at a landscape scale. Implications Movement of subadult rabbits between warrens is therefore likely to play a critical role in disease transmission, particularly when population density is low. This may help to explain the prevalent seasonality of RHD epizootics in spring when first-born litters of each breeding season typically reach that size.



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