scholarly journals Assessing the Effectiveness of Tuberculosis Management in Brushtail Possums (Trichosurus vulpecula), through Indirect Surveillance ofMycobacterium bovisInfection Using Released Sentinel Pigs

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
G. Nugent ◽  
I. J. Yockney ◽  
E. J. Whitford ◽  
M. L. Cross

In New Zealand, wild pigs acquireMycobacterium bovisinfection by scavenging tuberculous carrion, primarily carcasses of the main disease maintenance host, the brushtail possum (Trichosurus vulpecula). We investigated the utility of captive-reared, purpose-released pigs as sentinels for tuberculosis (TB) following lethal possum control and subsequent population recovery. Within 2-3 years of possum control by intensive poisoning, TB prevalence and the incidence rate ofM. bovisinfection in released sentinel pigs were lower than in an adjacent area where possums had not been poisoned. Unexpectedly, TB did not decline to near zero levels among pigs in the poisoned area, a fact which reflected an unanticipated rapid increase in the apparent abundance of possums. Monitoring infection levels among resident wild pigs confirmed that TB prevalence, while reduced due to possum control, persisted in the poisoned area at >20% among pigs born 2-3 years after poisoning, while remaining >60% among resident wild pigs in the nonpoisoned area. When fitted with radio-tracking devices, purpose-released pigs provided precise spatial TB surveillance information and facilitated effective killing of wild pigs when employed as “Judas” animals to help locate residents. Sentinel pigs offer value for monitoring disease trends in New Zealand, as TB levels in possums decline nationally due to large-scale possum control.

2019 ◽  
Vol 43 (2) ◽  
Author(s):  
Ron Jackson ◽  
D.U. Pfeiffe ◽  
T Porphyre ◽  
C Sauter-Louis ◽  
L.A.L. Corner ◽  
...  

1986 ◽  
Vol 96 (3) ◽  
pp. 431-438 ◽  
Author(s):  
D. M. Collins ◽  
G. W. De Lisle ◽  
D. M. Gabric

SUMMARYDNA restriction endonuclease analysis was used for intra-specific typing ofMycobacterium bovisisolates from 83 brush-tailed possums (Trichosurus vulpecula) obtained between 1982 and 1984 from the three major regions in New Zealand with endemic bovine tuberculosis. All the isolates were found to be genetically very similar. Differentiation of the isolates into 33 restriction types was achieved by using high-resolution electrophoresis and the combined results from separate digestions with the restriction enzymesBstEII,PvuII andBclI. The typing system was entirely reproducible. Isolates of the same type were usually found in adjacent localities and were always limited to one of the three major regions. In some cases, isolates of the same type were found in both 1982 and 1984. The phenotypic significance of the small genetic differences identified between different isolates is unknown. The typing system will be useful for monitoring the transmission ofM. bovisto other species and the future spread of differentM. bovistypes through possum populations.


1995 ◽  
Vol 22 (5) ◽  
pp. 579 ◽  
Author(s):  
SE Jolly ◽  
RJ Henderson ◽  
C Frampton ◽  
CT Eason

The common brushtail possum (Trichosurus vulpecula), an introduced pest in New Zealand, is susceptible to cholecalciferol (vitamin D3), which is marketed as a rodenticide in many countries. To evaluate cholecalciferol for possum control we offered 242 caged adult possums cereal pellets containing cholecalciferol on its own or with calcium carbonate. Mortality was recorded for two weeks after presentation. For cholecalciferol on its own the LD50 was 16.8 mg kg-1 (95% confidence interval 11.6-21.9 mg kg-1), but the addition of calcium carbonate reduced this to 9.8 mg kg-1 (95% confidence interval 7.0-12.7 mg kg-1). When the sexes were analysed separately, the reduction of the LDS0 by the addition of calcium carbonate was significant only in females. The addition of calcium carbonate appeared to result in a more predictable outcome as shown by the reduced confidence intervals. For possum control, adding calcium carbonate to cholecalciferol bait would improve the bait's efficacy, decrease the amount of toxic material needed, and reduce the cost of bait production.


2012 ◽  
Vol 153 ◽  
pp. 143-152 ◽  
Author(s):  
Christopher Jones ◽  
Mandy Barron ◽  
Bruce Warburton ◽  
Morgan Coleman ◽  
Philip O’B. Lyver ◽  
...  

2013 ◽  
Vol 40 (7) ◽  
pp. 561 ◽  
Author(s):  
Peter J. Sweetapple ◽  
Wendy A. Ruscoe ◽  
Graham Nugent

Context Efforts to protect or restore degraded plant communities by population control of invasive herbivores frequently fail to achieve their goals. Aims We seek to quantify changes in diet of an introduced herbivore, the brushtail possum (Trichosurus vulpecula), following population control, and determine how these may contribute to variable responses in plant condition. Methods Stomach contents of possums from five areas of indigenous forest in northern New Zealand were analysed to measure diet before and after the application of possum control. Key results The contribution of fruit, and foliage of some early successional forest species, to total possum diet increased up to 27-fold following possum population control. This was accompanied by declines in consumption of the main pre-control possum foods (foliage from common canopy trees). Dietary changes were a combination of an immediate response to control (1 year) and a strengthening of these initial changes with increasing time since control. Conclusions Possums in the study areas changed diet following population control, from a diet dominated by foliage of common canopy tree species to one dominated by fruits, and foliage of uncommon early successional plants. Pest control instantaneously increased the per capita availability of all foods, and probably permitted absolute increases in some foods through plant recovery, enabling possums to substitute scarce, high-preference foods for abundant but less preferred canopy foliage. Implications Following control of a pest herbivore, dietary changes reduce benefits for the most vulnerable preferred plant foods, but enhance benefits for less favoured plants. Intense pest control can permit some recovery of highly preferred foods, despite increased per capita consumption of these foods by survivors of control.


1996 ◽  
Vol 23 (2) ◽  
pp. 237 ◽  
Author(s):  
PE Cowan ◽  
RE Brockie ◽  
GD Ward ◽  
MG Efford

Long-distance movements of juvenile male and female brushtail possums (Trichosurus vulpecula) at a farmland site, Hawke's Bay, New Zealand, were studied by radio-tracking. About 20% of radio-tagged possums dispersed more than 2 km, moving up to 11.5 km from their natal area, most in a north-easterly direction. The proportion of males that dispersed was higher than that of females, but the difference was not statistically significant. All juveniles dispersing did so before they were one year old. The bimodal timing of dispersal in summer and late winter to early spring reflected an underlying similar pattern of breeding. Most possums made several moves before settling. A higher proportion of possums dispersed from the lowdensity area of pastoral and cropping land than from the higher-density areas of swamp and willows. A few dispersal records of ear-tagged animals were also obtained; most records were of males from the area of pastoral and cropping land, and movements ranged from 3 to 25 km.


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