Risk factors for bovine tuberculosis in New Zealand cattle farms and their relationship with possum control strategies

2008 ◽  
Vol 86 (1-2) ◽  
pp. 93-106 ◽  
Author(s):  
Thibaud Porphyre ◽  
Mark A. Stevenson ◽  
Joanna McKenzie
Author(s):  
Tabassom Sedighi ◽  
Liz Varga

Controlling bovine tuberculosis (bTB) disease in cattle farms in England is seen as a challenge for farmers, animal health, environment and policy-makers. The difficulty in diagnosis and controlling bTB comes from a variety of factors: the lack of an accurate diagnostic test which is higher in specificity than the currently available skin test; isolation periods for purchased cattle; and the density of active badgers, especially in high-risk areas. In this paper, to enable the complex evaluation of bTB disease, a dynamic Bayesian network (DBN) is designed with the help of domain experts and available historical data. A significant advantage of this approach is that it represents bTB as a dynamic process that evolves periodically, capturing the actual experience of testing and infection over time. Moreover, the model demonstrates the influence of particular risk factors upon the risk of bTB breakdown in cattle farms.


Author(s):  
G.W. De Lisle

Control strategies based on the slaughter of cattle identified as infected by skin testing have been successful in eradicating bovine tuberculosis from several countries. In contrast, identical control methods have not achieved eradication in New Zealand. The reason for the persistence of tuberculosis in New Zealand is the presence of a wildlife reservoir of infection. While possums are the principal wildlife reservoir of bovine tuberculosis, feral pigs and wild deer may also be a source of infection for domestic animals. Current control programmes in which possums are poisoned are successful in reducing but not eliminating the spread of infection to cattle and farmed deer. The development of vaccines and the biological control of possums is the focus of active research in New Zealand. These are long-term research projects that will take many years before they can be sufficiently developed to be used to eradicate bovine tuberculosis from this country. Keywords: bovine tuberculosis, cattle, farmed deer, Mycobacterium bovis, possums


Parasitology ◽  
2014 ◽  
Vol 141 (7) ◽  
pp. 981-987 ◽  
Author(s):  
Z. Y. X. HUANG ◽  
C. XU ◽  
F. VAN LANGEVELDE ◽  
H. H. T. PRINS ◽  
K. BEN JEBARA ◽  
...  

SUMMARYCurrent theories on disease-diversity relationships predict a strong influence of host richness on disease transmission. In addition, identity effect, caused by the occurrence of particular species, can also modify disease risk. We tested the richness effect and the identity effects of mammal species on bovine tuberculosis (bTB), based on the regional bTB outbreak data in cattle from 2005–2010 in Africa. Besides, we also tested which other factors were associated with the regional bTB persistence and recurrence in cattle. Our results suggested a dilution effect, where higher mammal species richness (MSR) was associated with reduced probabilities of bTB persistence and recurrence in interaction with cattle density. African buffalo had a positive effect on bTB recurrence and a positive interaction effect with cattle density on bTB persistence, indicating an additive positive identity effect of buffalo. The presence of greater kudu had no effect on bTB recurrence or bTB persistence. Climatic variables only act as risk factors for bTB persistence. In summary, our study identified both a dilution effect and identity effect of wildlife and showed that bTB persistence and recurrence were correlated with different sets of risk factors. These results are relevant for more effective control strategies and better targeted surveillance measures in bTB.


2007 ◽  
Vol 38 (3) ◽  
pp. 465-479 ◽  
Author(s):  
Thibaud Porphyre ◽  
Joanna McKenzie ◽  
Mark Stevenson

2021 ◽  
Vol 35 (2) ◽  
pp. 351-359
Author(s):  
Yassin K. Hamed ◽  
Essam Nasr ◽  
Mohamed Azooz ◽  
Hassan Youssef

2016 ◽  
Vol 144 (14) ◽  
pp. 2899-2926 ◽  
Author(s):  
J. M. BROUGHAN ◽  
J. JUDGE ◽  
E. ELY ◽  
R. J. DELAHAY ◽  
G. WILSON ◽  
...  

SUMMARYBovine tuberculosis (bTB) is an important disease of cattle caused by infection withMycobacterium bovis, a pathogen that may be extremely difficult to eradicate in the presence of a true wildlife reservoir. Our objective was to identify and review relevant literature and provide a succinct summary of current knowledge of risk factors for transmission of infection of cattle. Search strings were developed to identify publications from electronic databases to February 2015. Abstracts of 4255 papers identified were reviewed by three reviewers to determine whether the entire article was likely to contain relevant information. Risk factors could be broadly grouped as follows: animal (including nutrition and genetics), herd (including bTB and testing history), environment, wildlife and social factors. Many risk factors are inter-related and study designs often do not enable differentiation between cause and consequence of infection. Despite differences in study design and location, some risk factors are consistently identified, e.g. herd size, bTB history, presence of infected wildlife, whereas the evidence for others is less consistent and coherent, e.g. nutrition, local cattle movements. We have identified knowledge gaps where further research may result in an improved understanding of bTB transmission dynamics. The application of targeted, multifactorial disease control regimens that address a range of risk factors simultaneously is likely to be a key to effective, evidence-informed control strategies.


1997 ◽  
Vol 32 (1-2) ◽  
pp. 57-75 ◽  
Author(s):  
N.D. Barlow ◽  
J.M. Kean ◽  
G. Hickling ◽  
P.G. Livingstone ◽  
A.B. Robson

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