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

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.

1978 ◽  
Vol 81 (2) ◽  
pp. 245-249 ◽  
Author(s):  
J. W. Edmonds ◽  
Rosamond C. H. Shepherd ◽  
I. F. Nolan

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.


1971 ◽  
Vol 69 (3) ◽  
pp. 331-346 ◽  
Author(s):  
W. R. Sobey ◽  
Dorothy Conolly

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.


1971 ◽  
Vol 19 (2) ◽  
pp. 129 ◽  
Author(s):  
RT Williams ◽  
I Parer

The dispersal of the European rabbit flea, S. cuniculi, through a population of wild rabbits in a 550-acre enclosure was studied. It took 18 months (June 1968 until November 1969), and two rabbit breeding seasons before S, cuniculi was found throughout the population. The number of fleas observed on individual rabbits was much higher during each rabbit bieeding season than in the non-breeding periods. In most cases, the spread of fleas into the various social groups of rabbits occurred during the rabbit breeding season, and appeared to take the form of fleas from an infested group of rabbits being dispersed to a neighbouring uninfested one. This dispersal of S, cuniculi coincided with the dispersal of juvenile rabbits, which were most heavily infested with rabbit fleas at the end of each rabbit breeding season. Three instances of fleas being dispersed to non-neighbouring social groups of rabbits were observed, and these occurred between the 1968 and 1969 rabbit breeding seasons. It is possible that in these cases the fleas were introduced by the dispersal of adult rabbits from warrens infested with S, cuniculi. The data support a previous suggestion that these fleas, on a non-breeding rabbit population, spend most of their time away from the host. in the rabbit burrows.


2007 ◽  
Vol 34 (7) ◽  
pp. 511 ◽  
Author(s):  
B. H. van Leeuwen ◽  
P. J. Kerr

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.


2021 ◽  
Vol 61 ◽  
pp. e20216184
Author(s):  
Jairo José Zocche ◽  
Fernando Carvalho ◽  
Ariovaldo Pereira Cruz-Neto

Cinclodes pabsti is an endemic passerine restricted to the highland areas in southern Brazil. The aim of this study was to provide information on its breeding biology. The nesting cavities along road cuts were monitored from May 2008 to March 2011. The survey was carried out monthly from May to July 2008, February to July 2009, 2010 (non-breeding season), weekly from August 2008 to January 2009, 2010 (breeding season), and on a 2 to 4-days basis from August 2010 to January 2011. The geographic location, physical characteristics, and soil/substrate type in which the nesting cavities were situated were recorded. The total number of cavities used in the three breeding seasons was 136, resulting in 295 nests. The distance of a nest to its nearest neighbor ranged from 24-2,368 m, with a higher number of nests (n = 34; 59.7%) in the distance interval of 24-500 m. There was a greater usage of cavities located in Inceptisols, and the distances of nesting cavity entrances to the ground and to the top of road cuts were 1.6 ± 0.9 m and 0.8 ± 0.62 m, respectively. The breeding season lasted 148 days from mid-August to early January. Clutch size (n = 256) varied from 2 to 3 eggs, and the eggs (n = 155) had a total length of 27.2 ± 1.3 mm, breadth of 20.9 ± 0.8 mm, and mass of 6.2 ± 0.7 g. The incubation phase lasted 17.3 ± 0.8 days and the nestling phase for 18.3 ± 1.5 days. The body mass of the chicks was 6.0 ± 1.0 g just after hatching and reached a maximum of 59.6 ± 2.4 g at 16 days of age. Our results can contribute to filling the gaps in knowledge of C. pabsti ecology, because its habitat is under high anthropic pressures and the information on its life history is yet limited.


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.


1954 ◽  
Vol 52 (3) ◽  
pp. 321-336 ◽  
Author(s):  
Frank Fenner ◽  
I. D. Marshall

1. The existence of passive immunity to myxomatosis was demonstrated by the inoculation of normal young rabbits with either myxoma-immune serum or saline, and their subsequent inoculation with the standard laboratory strain of myxoma virus. All the passively immunized animals lived longer than the control animals and a few survived.2. Passive immunity could also be demonstrated in the offspring of myxoma-immune mothers. When these were challenged by mosquito bite inoculation with the standard laboratory strain of myxoma virus they either failed to become infected, or survived infection for several days longer than the progeny of normal does. When challenged by the intradermal inoculation of a slightly attenuated strain of myxoma virus 25 % of the progeny of immune does survived the infection, whereas none of the normal kittens survived.3. The survival times of young rabbits in both the normal and passively immunized groups was influenced by their age, very young animals dying several days earlier than rabbits 4 and 6 weeks old.4. The possible epidemiological consequences of passive immunity in the behaviour of myxomatosis in populations of wild rabbits are discussed.


1981 ◽  
Vol 8 (2) ◽  
pp. 361 ◽  
Author(s):  
RCH Shepherd ◽  
JW Edmonds ◽  
IF Nolan

There was a preponderance of females in wild rabbits collected in Victoria before 1974. This preponderance was established in subadults; in adults the sex ratio tended towards equality or a preponderance of males. The preponderance of females was most marked after the breeding season. A change to male preponderance in the Mallee region coincided with the establishment of the European rabbit flea.


1981 ◽  
Vol 8 (3) ◽  
pp. 581 ◽  
Author(s):  
SH Wheeler ◽  
DR King ◽  
MH Robinson

'Rabbits equipped with miniature radio transmitters were located when at rest during the day at Cape Naturaliste, W.A. The study site was open pasture with numerous warrens, surrounded by and containing patches of native vegetation in which there were few warrens. Rabbits for instrumentation were live-trapped on the pasture and were located by radio once per day during each of four tracking periods in February, March-April (non-breeding season), May, and June (breeding season). A total of 31 individuals provided 284 locations, 263 (93%) of which were in the scrub. Of 216 locations in the scrub where the position of the rabbit (above or below ground) was known, 164 (765%) were above ground. Individual rabbits were found at several places within their resting areas, some of which were over 100 m into the scrub. The relevance of these results to current methods of rabbit control is discussed.


1998 ◽  
Vol 25 (2) ◽  
pp. 97 ◽  
Author(s):  
Laurie E. Twigg ◽  
Tim J. Lowe ◽  
Gary R. Martin ◽  
Amanda G. Wheeler ◽  
Garry S. Gray ◽  
...  

Demographic changes in three free-ranging rabbit (Oryctolagus cuniculus) populations were monitored over 4 years in southern Western Australia. Peak densities followed periods of high rainfall and pasture biomass. The breeding season was prolonged, often extending from at least April to November, with some pregnancies occurring outside this period. Fecundity, determined by the autopsy of pregnant offsite rabbits and the known length of each breeding season, appeared to be relatively high, with the potential for 34–39 kittens doe-1 year-1; however, because not all females are pregnant in all months, the overall productivity of these populations was estimated at 25–30 kittens adult female-1 year-1. Exponential rates of increase varied from 0.13 to 0.30 during the breeding periods and –0.05 to –0.14 during the nonbreeding season. Kitten survival was generally low whereas some adults lived for more than 5 years. Two patterns of myxomatosis were observed: annual epizootics of the disease (3 of 4 years) and an epidemic that slowly spread over many months. European rabbit fleas were most abundant during winter–spring and attained highest densities on adult female rabbits.


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