scholarly journals Timing and severity of immunizing diseases in rabbits is controlled by seasonal matching of host and pathogen dynamics

2015 ◽  
Vol 12 (103) ◽  
pp. 20141184 ◽  
Author(s):  
Konstans Wells ◽  
Barry W. Brook ◽  
Robert C. Lacy ◽  
Greg J. Mutze ◽  
David E. Peacock ◽  
...  
Keyword(s):  
Local Population ◽  
Disease Outbreaks ◽  
Maternal Antibodies ◽  
Timing Of Reproduction ◽  
Demographic Rates ◽  
Pathogen Dynamics ◽  
Rabbit Haemorrhagic Disease ◽  
Seasonal Epidemics ◽  
Haemorrhagic Disease

Infectious diseases can exert a strong influence on the dynamics of host populations, but it remains unclear why such disease-mediated control only occurs under particular environmental conditions. We used 16 years of detailed field data on invasive European rabbits ( Oryctolagus cuniculus ) in Australia, linked to individual-based stochastic models and Bayesian approximations, to test whether (i) mortality associated with rabbit haemorrhagic disease (RHD) is driven primarily by seasonal matches/mismatches between demographic rates and epidemiological dynamics and (ii) delayed infection (arising from insusceptibility and maternal antibodies in juveniles) are important factors in determining disease severity and local population persistence of rabbits. We found that both the timing of reproduction and exposure to viruses drove recurrent seasonal epidemics of RHD. Protection conferred by insusceptibility and maternal antibodies controlled seasonal disease outbreaks by delaying infection; this could have also allowed escape from disease. The persistence of local populations was a stochastic outcome of recovery rates from both RHD and myxomatosis. If susceptibility to RHD is delayed, myxomatosis will have a pronounced effect on population extirpation when the two viruses coexist. This has important implications for wildlife management, because it is likely that such seasonal interplay and disease dynamics has a strong effect on long-term population viability for many species.

Habitat factors related to wild rabbit population trends after the initial impact of rabbit haemorrhagic disease

2006 ◽  
Vol 33 (6) ◽  
pp. 467 ◽  
Author(s):  
Carlos Calvete ◽  
Enrique Pelayo ◽  
Javier Sampietro
Keyword(s):  
Habitat Quality ◽  
Population Trends ◽  
Wild Rabbit ◽  
Pest Species ◽  
Predator Species ◽  
Rabbit Population ◽  
Habitat Factors ◽  
Rabbit Haemorrhagic Disease ◽  
Haemorrhagic Disease

The European wild rabbit (Oryctolagus cuniculus) is an introduced pest species in Australia and New Zealand. Rabbits have a devastating negative impact on agricultural production and biodiversity in these countries, and Rabbit Haemorrhagic Disease (RHD) is currently included in control strategies for rabbit populations. On the other hand, the European wild rabbit is a key native prey species in the Iberian Peninsula. Since the arrival of RHD, however, rabbit populations have undergone dramatic decreases and several predator species at risk of extinction are currently dependent on the rabbit population density. Therefore, from the point of view of biodiversity conservation, evaluating habitat correlates and trends of rabbit populations after the first RHD epizootic is of great interest to improve the long-term control or promotion of wild rabbit populations. We estimated the relationship between habitat factors and long-term population trends as well as the relationships between habitat factors and rabbit abundance 2 and 14 years after the arrival of RHD in several Iberian rabbit populations. We observed that only 26% of surveyed populations seemed to experience an increase in rabbit abundance over the last 12 years and that this increase was higher in the low-rabbit-abundance areas of l992, leading to high rabbit abundance in 2004. Our results suggested that short- and long-term impacts of RHD were related to habitat quality. The initial impact of RHD was higher in more suitable habitats, but increasing long-term population trends were positively related to good habitat quality.

Substantial numerical decline in South Australian rabbit populations following the detection of rabbit haemorrhagic disease virus 2

2018 ◽  
Vol 182 (20) ◽  
pp. 574-574 ◽  
Author(s):  
Greg Mutze ◽  
Nicki De Preu ◽  
Trish Mooney ◽  
Dylan Koerner ◽  
Darren McKenzie ◽  
...  
Keyword(s):  
Disease Virus ◽  
South Australia ◽  
Rabbit Haemorrhagic Disease Virus ◽  
Environmental Benefit ◽  
Rabbit Haemorrhagic Disease ◽  
European Rabbits ◽  
Haemorrhagic Disease ◽  
The Impact ◽  
Term Monitoring

Lagovirus europaeus GI.2, also commonly known as rabbit haemorrhagic disease virus 2, was first detected at two long-term monitoring sites for European rabbits, Oryctolagus cuniculus, in South Australia, in mid-2016. Numbers of rabbits in the following 12–18 months were reduced to approximately 20 per cent of average numbers in the preceding 10 years. The impact recorded at the two South Australian sites, if widespread in Australia and persistent for several years, is likely to be of enormous economic and environmental benefit.

Long-term impact of coordinated warren ripping programmes on rabbit populations

2010 ◽  
Vol 37 (1) ◽  
pp. 68 ◽  
Author(s):  
S. R. McPhee ◽  
K. L. Butler
Keyword(s):  
Population Decline ◽  
Biological Control Agents ◽  
Control Effort ◽  
Rabbit Haemorrhagic Disease ◽  
Long Term Impact ◽  
Haemorrhagic Disease ◽  
The Impact ◽  
The Relationship

Context. It is important to examine the long-term effectiveness of rabbit management programmes based on warren destruction using modern warren ripping machinery, at a time when the continuing impacts of both myxomatosis and rabbit haemorrhagic disease (RHD) may have reduced the capacity of rabbit populations to recover. Aims. To determine the long-term effectiveness of coordinated warren ripping programmes in reducing rabbit densities and maintaining these low densities. Methods. Commencing in 1998, 14 sites with coordinated warren ripping programmes and three sites without rabbit control were monitored within Victoria. Spotlight counts of rabbit numbers recorded before the spread of RHD and warren ripping were compared with numbers recorded from 2005 to 2008. The efficacy of coordinated warren ripping programmes was assessed in relation to the machinery used, the manner in which the warrens were ripped, the characteristics of the ripped areas and the impact of follow-up control. Key results. Warren ripping programmes were very successful in reducing rabbit numbers for up to 10 years, whereas rabbit populations that were not managed returned to pre-RHD densities. The most effective warren ripping programmes, which reduced populations to 97% of the pre-RHD densities and maintained them at this level, used heavy, powerful ripping machinery to rip all warrens within 12 months. There was no evidence that the relationship between rabbit population decline and warren ripping was affected by the characteristics of the ripped areas or the follow-up control effort. Conclusions. Following the spread of RHD in areas where warren ripping is practicable, well-managed ripping programmes provide an immediate solution for achieving and sustaining low rabbit populations. Implications. The efficacy of RHD in regulating rabbit populations has diminished. The improvement of existing or the development of new biological control agents could take decades. In contrast, coordinated warren ripping programmes provide more predictable long-term reductions in rabbit populations.

Does a benign calicivirus reduce the effectiveness of rabbit haemorrhagic disease virus (RHDV) in Australia? Experimental evidence from field releases of RHDV on bait

2010 ◽  
Vol 37 (4) ◽  
pp. 311 ◽  
Author(s):  
Greg Mutze ◽  
Ron Sinclair ◽  
David Peacock ◽  
John Kovaliski ◽  
Lorenzo Capucci
Keyword(s):  
Disease Virus ◽  
Disease Outbreaks ◽  
Wild Rabbit ◽  
Rabbit Haemorrhagic Disease Virus ◽  
Agricultural Pests ◽  
Genetic Sequencing ◽  
Rabbit Haemorrhagic Disease ◽  
Almost All ◽  
Haemorrhagic Disease ◽  
The Impact

Context. European rabbits are serious environmental and agricultural pests throughout their range in Australia. Rabbit haemorrhagic disease virus (RHDV) greatly reduced rabbit numbers in arid central Australia but had less impact in cooler, higher-rainfall areas. RHDV-like benign caliciviruses (bCVs) have been implicated in limiting the impact of RHDV in the higher-rainfall regions of Australia and also in Europe. Aims. Experimental releases of RHDV on bait were tested as a means of initiating disease outbreaks. Serological evidence of antibodies to bCVs was examined to determine whether they reduce mortality rates and/or spread of the released RHDV, and how that might influence the effectiveness of future RHDV releases for rabbit management. Methods. Four experimental releases were conducted in high-rainfall and coastal regions of southern Australia. Virus activity was implied from recapture rates and serological changes in marked rabbits, and genetic sequencing of virus recovered from dead rabbits. Changes in rabbit abundance were estimated from spotlight transect counts. Key results. Release of RHDV on bait produced disease outbreaks that challenged almost all animals within the general release area and spread up to 4 km beyond the release sites. Recapture rates were high in marked rabbits that possessed antibodies from previous exposure to RHDV and extremely low amongst rabbits that lacked any detectable antibodies. Rabbits carrying antibodies classified as being due to previous infection with bCVs had recapture rates that were dependent on circulating antibody titre and were ~55% of recapture rates in rabbits with clear antibodies to RHDV. Conclusions. This is the first quantified evidence that antibodies produced against bCVs provide significant protection against RHD outbreaks in field populations of rabbits. Implications. bCVs can greatly reduce the impact of RHDV on wild-rabbit populations in Australia and presumably elsewhere. RHDV can be effectively released on bait although further releases are likely to be of minor or inconsistent benefit for controlling rabbit numbers where bCVs are common.

scholarly journals Use of ELISAs in field studies of rabbit haemorrhagic disease (RHD) in Australia

2000 ◽  
Vol 124 (3) ◽  
pp. 563-576 ◽  
Author(s):  
B. D. COOKE ◽  
A. J. ROBINSON ◽  
J. C. MERCHANT ◽  
A. NARDIN ◽  
L. CAPUCCI
Keyword(s):  
Field Studies ◽  
Antibody Responses ◽  
Maternal Antibodies ◽  
Disease Spread ◽  
Data Set ◽  
Immunological Status ◽  
Rabbit Haemorrhagic Disease ◽  
Domestic Rabbits ◽  
Haemorrhagic Disease ◽  
Reliable Basis

ELISA techniques developed for the veterinary diagnosis of Rabbit Haemorrhagic Disease (RHD) in domestic rabbits were used for studying the epidemiology of RHD in Australian wild rabbits. The combination of ELISA techniques that distinguished IgA, IgG and IgM antibody responses and a longitudinal data set, mainly based on capture-mark-recapture of rabbits, provided a reliable basis for interpreting serology and set the criteria used to classify rabbits' immunological status. Importantly, young with maternal antibodies, immune rabbits and rabbits apparently re-exposed to RHD were readily separated. Three outbreaks of RHD occurred in 1996–7. The timing of RHD outbreaks was mainly driven by recruitment of young rabbits that generally contracted RHD after they lost their maternally derived immunity. Young that lost maternal antibodies in summer were not immediately infected, apparently because transmission of RHDV slows at that time, but contracted RHD in the autumn when conditions were again suitable for disease spread.

Rabbit haemorrhagic disease in New Zealand: field test of a disease - host model

2002 ◽  
Vol 29 (6) ◽  
pp. 649 ◽  
Author(s):  
N. D. Barlow ◽  
M. C. Barron ◽  
J. Parkes
Keyword(s):  
New Zealand ◽  
Qualitative Data ◽  
Virus Transmission ◽  
Transmission Mechanism ◽  
Free Living ◽  
Additional Control ◽  
Rabbit Haemorrhagic Disease ◽  
Haemorrhagic Disease ◽  
Antibody Levels

An earlier published model, parameterised from qualitative data from Europe and detailed observations of the first simple epidemic in Australia, gave a good fit to longer-term (3 year) data from New Zealand, without any re-tuning of parameters. Changing some of the unknown disease parameters further improved the model's fit, but two problems remained. Firstly, predicted proportions seropositive are too high if rabbit densities are as low as observed, and if the proportions seropositive are correct then the predicted densities are too high. Secondly, observed rabbit densities do not show obvious peaks of recruitment, as predicted by the model with and without RHD. Possible reasons for these discrepancies are suggested, and initial trials with the model suggested that a novel transmission mechanism involving both direct (rabbit to rabbit) and indirect (via free-living virus) transmission may help explain both high suppression and low antibody levels. The main conclusions from the original model remain unaffected by its testing against new data, namely: rabbit populations are likely to be suppressed in the long term by about 75%; the pattern of epidemics is determined largely by intrinsic disease behaviour rather than seasonality, though the latter may tune this to some extent; there tend to be yearly epidemics; percentages of rabbits infected at any one time are low (around 5%) but this does not imply low impact; maternal antibodies have little effect on RHD dynamics; RHD may persist in low-density as well as high-density populations but give less suppression; and additional control may eradicate disease, at least temporarily.

scholarly journals Have Lesser Scaup, Aythya affinis, Reproductive Rates Declined in Parkland Manitoba?

2003 ◽  
Vol 117 (4) ◽  
pp. 582 ◽  
Author(s):  
David N. Koons ◽  
Jay J. Rotella
Keyword(s):  
Local Population ◽  
Population Decline ◽  
Proximate Cause ◽  
Aythya Affinis ◽  
The Past ◽  
Duckling Survival ◽  
Demographic Rates ◽  
Lesser Scaup ◽  
Reproductive Rates

Long-term surveys indicate that the scaup populations have declined over the past 20 years, and that this is probably the result of decreases in Lesser Scaup (Aythya affinis) rather than Greater Scaup (Aythya marila) numbers. To identify factors possibly related to the decline, we estimated demographic parameters for a local population of Lesser Scaup at Erickson, Manitoba, that was well studied before declines occurred and compared these estimates to historic rates. On average, nests were initiated later than in the past, and recent estimates of nesting success and duckling survival were lower than historical estimates. Breeding-season survival of adult females was estimated as 72.6%, with most (83%) mortality occurring during nesting. Current estimates of demographic rates at Erickson are too low to maintain a stable local population, and suppressed reproductive rates might be the proximate cause of the local population decline.

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