scholarly journals Myxomatosis: the occurrence of antibody to a soluble antigen of myxoma virus in wild rabbits, Oryctolagus cuniculus (L.), in Victoria, Australia

1978 ◽  
Vol 81 (2) ◽  
pp. 245-249 ◽  
Author(s):  
J. W. Edmonds ◽  
Rosamond C. H. Shepherd ◽  
I. F. Nolan
Keyword(s):  
Breeding Season ◽  
Infection Rate ◽  
Oryctolagus Cuniculus ◽  
Myxoma Virus ◽  
European Rabbit ◽  
Soluble Antigen ◽  
Relative Timing ◽  
North West ◽  
The North ◽  
Semi Arid

SummaryThe occurrence of antibody to myxoma virus in wild rabbits following epizootics is highest in the semi-arid north-west of Victoria and lowest in temperate southern Victoria. Occurrence ranges up to about 90% in the north-west and to about 70% in the south except on the Western Plains where epizootics are rare and antibody occurrence seldom exceeds 30%.The establishment of the European rabbit flea may be changing the pattern of occurrence of antibody in the north-west by causing spring outbreaks of myxomatosis. It is suggested that the effects of the replacement of a simple recurring system of epizootic and breeding season several months apart by the occurrence of myxomatosis twice in the same year, once coincident with the breeding season, will be complex. The occurrence of detectable antibody may be less dependent on the infection rate and may be dependent to some extent on the relative timing of spring myxomatosis and the breeding season.

Population Fluctuations and Reproduction of Rabbits in a Pastoral Area on the Coast North of Carnarvon, W. A.

1983 ◽  
Vol 10 (1) ◽  
pp. 97 ◽  
Author(s):  
DR King ◽  
SH Wheeler ◽  
GL Schmidt
Keyword(s):  
Breeding Season ◽  
Oryctolagus Cuniculus ◽  
Cost Effective ◽  
Effective Control ◽  
Population Fluctuations ◽  
North West ◽  
The North ◽  
Pastoral Area ◽  
Average Rainfall ◽  
Summer Rain

The population fluctuations and reproductive biology of rabbits, Oryctolagus cuniculus (L.), were studied in a coastal pastoral area in the north-west of Western Australia between 1974 and 1981. Numbers were highest in late 1975-early 1976 and declined during a period of below-average rainfall in 1976-79, but were still found in all landforms. The breeding season was more regular than that of rabbits in other pastoral areas, and appeared to be a response to winter rains which were relatively predictable in timing, if not amount. Successful summer breeding also followed heavy summer rain. There appears to be no opportunity for cost-effective control of rabbits in the area by techniques currently available, as even when numbers are low the rabbits are widespread.

The Establishment and Spread of Spilopsyllus Cuniculi (Dale) and Its Location on the Host, Oryctolagus Cuniculus (L.), In the Mallee Region of Victoria.

1976 ◽  
Vol 3 (1) ◽  
pp. 29 ◽  
Author(s):  
RCH Shepherd ◽  
JW Edmonds
Keyword(s):  
Breeding Season ◽  
Oryctolagus Cuniculus ◽  
Myxoma Virus ◽  
The Body ◽  
European Rabbit ◽  
Initial Release ◽  
Breeding Seasons

European rabbit fleas (Spilopsyllus cuniculi) (Dale)) were released into a population of wild rabbits at 7 sites on Pine Plains in the Mallee district of Victoria, Australia, and their establishment and distribution observed monthly for 4 years. After 12 months, including one breeding season, the fleas were found on some rabbits up to 0.8 km from some release sites. By the end of the second breeding season, the distance of spread had doubled, and 4 years after the initial release, including 5 breeding seasons, about 95% of rabbits caught carried S. cuniculi. The furthest spread was about 13 km. When the initial release was made during the summer months, the non-breeding season, spread was slow; in one area, it took 2 years for S. cuniculi to become firmly established. When examples of S. cuniculi infected with myxoma virus were released, no establishment of the disease was observed. The numbers of S. cuniculi per rabbit were low during the first breeding season, but they were high, up to 500/rabbit, after 4 years. In most cases, the fleas were seen on the ears, pinnae and head of the rabbit and occasionally in the body fur. The highest numbers were usually found on pregnant lactating does about to litter, but some bucks also carried a large number.

Agriculture expansion and deforestation in seasonally dry forests of north-west Argentina

2005 ◽  
Vol 32 (2) ◽  
pp. 140-148 ◽  
Author(s):  
H. RICARDO GRAU ◽  
N. IGNACIO GASPARRI ◽  
T. MITCHELL AIDE
Keyword(s):  
Global Trends ◽  
North West ◽  
Conservation Policies ◽  
Seasonally Dry ◽  
The North ◽  
Agriculture Expansion ◽  
Soybean Price ◽  
Different Levels ◽  
Semi Arid ◽  
Arid Chaco

In Argentina, deforestation due to agriculture expansion is threatening the Semi-arid Chaco, one of the largest forested biomes of South America. This study focuses on the north-west boundary of the Argentine Semi-arid Chaco, where soybean is the most important crop. Deforestation was estimated for areas with different levels of soil and rainfall limitation for agriculture between 1972 and 2001, with a finer analysis in three periods starting in 1984, which are characterized by differences in rainfall, soybean price, production cost, technology-driven yield and national gross domestic product. Between 1972 and 2001, 588 900 ha (c. 20% of the forests) were deforested. Deforestation has been accelerating, reaching >28 000 ha yr−1 after 1997. The initial deforestation was associated with black bean cultivation following an increase in rainfall during the 1970s. In the 1980s, high soybean prices stimulated further deforestation. Finally, the introduction of soybean transgenic cultivars in 1997 reduced plantation costs and stimulated a further increase in deforestation. The domestic economy had little association with deforestation. Although deforestation was more intense in the moister (rainfall >600 mm yr−1) areas, more than 300 000 ha have already been deforested in the drier areas, suggesting that climatic limitations are being overcome by technological and genetic improvement. Furthermore, more than 300 000 ha of forest occur in sectors without major soil and rainfall limitations. If global trends of technology, soybean markets and climate continue, and no active conservation policies are applied, vast areas of the Chaco will be deforested in the coming decades.

Prospects for fertility control in the European rabbit (Oryctolagus cuniculus) using myxoma virus-vectored immunocontraception

2007 ◽  
Vol 34 (7) ◽  
pp. 511 ◽  
Author(s):  
B. H. van Leeuwen ◽  
P. J. Kerr
Keyword(s):  
Laboratory Testing ◽  
Oryctolagus Cuniculus ◽  
Field Testing ◽  
Fertility Control ◽  
Epidemiological Studies ◽  
Myxoma Virus ◽  
European Rabbit ◽  
Medium Term ◽  
Delivery Vector ◽  
Virus Research

Research over the last 15 years has examined whether fertility control can reduce overabundant rabbit populations and whether an effective immunocontraceptive agent can be developed and delivered. The results of this research indicate that for fertility control to have an environmental impact at least 80% of females will need to be infertile and that this infertility will need to be permanent. Epidemiological studies suggest that this level of infertility may be very difficult to obtain with a recombinant myxoma virus because of competition with field strains of virus. Research with laboratory rabbits using recombinant myxoma virus to deliver an immunocontraceptive antigen demonstrated that it was possible to obtain the required level of infertility using rabbit zona pellucida C as an antigen. However, only ~50% of animals remained infertile in the medium term. Further research on delivery vector and antigen selection would be needed to produce a practical immunocontraceptive virus for laboratory testing. Such a virus would then need to be optimised for transmissibility before it would be suitable for field testing.

scholarly journals Fluctuations in the titre of antibody to a soluble antigen of myxoma virus in field populations of rabbits,Oryctolagus cuniculus(L.), in Australia

1973 ◽  
Vol 71 (3) ◽  
pp. 487-500 ◽  
Author(s):  
R. T. Williams ◽  
J. D. Dunsmore ◽  
W. R. Sobey
Keyword(s):  
Immune Response ◽  
Antibody Titre ◽  
Oryctolagus Cuniculus ◽  
Myxoma Virus ◽  
Soluble Antigen ◽  
Virus Reactivation ◽  
The Past ◽  
Stimulation Of

SUMMARYResults are presented on tests carried out over the past 5 years to measure the antibody titre of various rabbit populations to a soluble antigen of myxoma virus. In an unexpectedly high percentage of immune rabbits the antibody fell below measurable titres, and later rose to measurable titres without the advent of an observable epizootic of myxomatosis. The re-stimulation of the immune response is discussed in terms of re-infection and virus reactivation.

scholarly journals Myxomatosis: the transmission of a highly virulent strain of myxoma virus by the European rabbit flea Spilopsyllus cuniculi (Dale) in the Mallee region of Victoria

1977 ◽  
Vol 79 (3) ◽  
pp. 405-409 ◽  
Author(s):  
Rosamond C. H. Shepherd ◽  
J. W. Edmonds
Keyword(s):  
Virulent Strain ◽  
Myxoma Virus ◽  
European Rabbit ◽  
Effective Transmission ◽  
Highly Virulent ◽  
Semi Arid

SUMMARYThe European rabbit flea Spilopsyllus cuniculi (Dale) was introduced into Australia to act as a vector of myxoma virus. It was first released in the semi-arid Mallee region of Victoria in 1970 where epizootics caused by field strains of myxoma virus occur each summer. Introductions of the readily identified Lausanne strain were made annually following the release of the flea. The introductions were successful and the strain persisted for up to 16 weeks despite competition from field strains.The Lausanne strain is more readily spread by fleas than the Glenfield strain which has been widely used in rabbit control. The ability of the Lausanne strain to persist and its effective transmission compared with the Glenfield strain may be due in part to the more florid symptoms of the disease.

scholarly journals Myxomatosis: the introduction of the European rabbit flea Spilopsyllus cuniculi (Dale) into wild rabbit populations in Australia

1971 ◽  
Vol 69 (3) ◽  
pp. 331-346 ◽  
Author(s):  
W. R. Sobey ◽  
Dorothy Conolly
Keyword(s):  
Breeding Season ◽  
New South ◽  
New South Wales ◽  
Release Site ◽  
Myxoma Virus ◽  
European Rabbit ◽  
Wild Rabbit ◽  
South Wales ◽  
Breeding Seasons

SUMMARY1. The European rabbit flea Spilopsyllus cuniculi (Dale) bred successfully in wild rabbits on three properties in New South Wales and, within two breeding seasons, almost every rabbit shot within a quarter of a mile of a release site was infested.2. It was demonstrated that the flea transmitted myxoma virus in the field.3. In areas where more than 75 % of the rabbits shot at the beginning of the breeding season were flea-infested and myxoma virus was present, populations failed to show the expected summer build-up.

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