scholarly journals Inferring Mycobacterium bovis transmission between cattle and badgers using isolates from the Randomised Badger Culling Trial

2021 ◽  
Author(s):  
Andries J van Tonder ◽  
Mark Thornton ◽  
Andrew JK Conlan ◽  
Keith A Jolley ◽  
Lee Goolding ◽  
...  
Keyword(s):  
Mycobacterium Bovis ◽  
Bovine Tuberculosis ◽  
Long Distance ◽  
Cattle Industry ◽  
Cattle Movement ◽  
Badger Culling ◽  
Movement Data ◽  
South West ◽  
Different Parts ◽  
South West England

Mycobacterium bovis (M. bovis) is a causative agent of bovine tuberculosis, a significant source of morbidity and mortality in the global cattle industry. The Randomised Badger Culling Trial was a field experiment carried out between 1998 and 2005 in the South West of England. As part of this trial, M. bovis isolates were collected from contemporaneous and overlapping populations of badgers and cattle within ten defined trial areas. We combined whole genome sequences from 1,442 isolates with location and cattle movement data, identifying transmission clusters and inferred rates and routes of transmission of M. bovis. Most trial areas contained a single transmission cluster that had been established shortly before sampling, often contemporaneous with the expansion of bovine tuberculosis in the 1980s. The estimated rate of transmission from badger to cattle was approximately two times higher than from cattle to badger, and the rate of within-species transmission considerably exceeded these for both species. We identified long distance transmission events linked to cattle movement, recurrence of herd breakdown by infection within the same transmission clusters and superspreader events driven by cattle but not badgers. Overall, our data suggests that the transmission clusters in different parts of South West England that are still evident today were established by long-distance seeding events involving cattle movement, not by recrudescence from a long-established wildlife reservoir. Clusters are maintained primarily by within-species transmission, with less frequent spill-over both from badger to cattle and cattle to badger.

scholarly journals Inferring Mycobacterium bovis transmission between cattle and badgers using isolates from the Randomised Badger Culling Trial

2021 ◽  
Vol 17 (11) ◽  
pp. e1010075
Author(s):  
Andries J. van Tonder ◽  
Mark J. Thornton ◽  
Andrew J. K. Conlan ◽  
Keith A. Jolley ◽  
Lee Goolding ◽  
...  
Keyword(s):  
Mycobacterium Bovis ◽  
Bovine Tuberculosis ◽  
Long Distance ◽  
Cattle Industry ◽  
Cattle Movement ◽  
Badger Culling ◽  
Movement Data ◽  
South West ◽  
Different Parts ◽  
South West England

Mycobacterium bovis (M. bovis) is a causative agent of bovine tuberculosis, a significant source of morbidity and mortality in the global cattle industry. The Randomised Badger Culling Trial was a field experiment carried out between 1998 and 2005 in the South West of England. As part of this trial, M. bovis isolates were collected from contemporaneous and overlapping populations of badgers and cattle within ten defined trial areas. We combined whole genome sequences from 1,442 isolates with location and cattle movement data, identifying transmission clusters and inferred rates and routes of transmission of M. bovis. Most trial areas contained a single transmission cluster that had been established shortly before sampling, often contemporaneous with the expansion of bovine tuberculosis in the 1980s. The estimated rate of transmission from badger to cattle was approximately two times higher than from cattle to badger, and the rate of within-species transmission considerably exceeded these for both species. We identified long distance transmission events linked to cattle movement, recurrence of herd breakdown by infection within the same transmission clusters and superspreader events driven by cattle but not badgers. Overall, our data suggests that the transmission clusters in different parts of South West England that are still evident today were established by long-distance seeding events involving cattle movement, not by recrudescence from a long-established wildlife reservoir. Clusters are maintained primarily by within-species transmission, with less frequent spill-over both from badger to cattle and cattle to badger.

scholarly journals Quantifying the risks of TB infection to cattle posed by badger excreta

1999 ◽  
Vol 122 (1) ◽  
pp. 167-174 ◽  
Author(s):  
M. R. HUTCHINGS ◽  
S. HARRIS
Keyword(s):  
High Risk ◽  
Mycobacterium Bovis ◽  
Disease Prevalence ◽  
Deterministic Approach ◽  
Main Route ◽  
South West ◽  
Route Of Transmission ◽  
Risk Areas ◽  
High Level ◽  
South West England

Despite strong circumstantial evidence to suggest that the main route of TB transmission from badgers to cattle is via contaminated badger excreta, it is unclear whether the associated risks are high enough to account for the prevalence of the disease in south-west England. To decide whether this was a viable route of transmission, cattle contact with badger excreta was investigated using a deterministic approach to quantify the risks to cattle posed by badger excreta. Levels of investigative and grazing contacts between cattle and badger urine and faeces could each account for the disease prevalence in south-west England. An infection probability of 3·7×10−4 per bite from pasture contaminated with badger urine infected with Mycobacterium bovis could account for the prevalence of TB in cattle in south-west England. Infection probabilities of 6·9×10−7 per investigation and 1·1×10−7 per bite from badger latrines could each account for the prevalence of TB in cattle in the south-west. When considering only the high risk areas of south-west England these bounds fell by a factor of eight. However, badger excreta may still constitute a high level of risk to cattle. The levels of cattle contact with badger excreta are far higher than previously thought, suggesting that it is the probability of infection per given contact with infected badger excreta which has the greater influence on the probability of transmission and not the level of contact. The infection probability per cattle contact with infected badger excreta is in all likelihood extremely low.

scholarly journals Bovine tuberculosis in cattle from 1986 to 2012 in and around badger-culled areas of the RBCT

2016 ◽  
Author(s):  
David Hendy
Keyword(s):  
Bovine Tuberculosis ◽  
Health Agency ◽  
Incidence Data ◽  
Badger Culling ◽  
Scientific Group ◽  
Surrounding Areas ◽  
The Uk ◽  
The Cost ◽  
The Impact ◽  
South West England

In 2007 the Independent Scientific Group (ISG) reported to the UK government the impact on bovine tuberculosis (TB) in cattle of a trial where badgers were culled between 1998 and 2005. This trial, known as the Randomised Badger Culling Trial (RBCT), was performed across 100 km2 (nominal) zones in the West of England. The results were based on a model of new herd incidence data. It was concluded that reactive culling generated overall detrimental effects, while proactive culling achieved very modest overall benefits at the cost of elevated incidence on neighbouring farms. This work looks at more extensive RBCT data to examine if these findings hold true. Instead of presenting the results of a model, this work directly illustrates data supplied in March 2016 by the Animal and Plant Health Agency. Such data covers a greater number of years (1986 to 2012) and includes the prevalence of herd restrictions as well as herd incidence. It appears that whilst cattle TB noticeably reduced in areas subjected to proactive culling, TB did not significantly increase in the surrounding areas. The more limited reactive culls were found to have no significant impact either positively or negatively. This applied to both the treated and surrounding areas. The more extensive data also showed that culling badgers only reduced confirmed TB with no significant impact on unconfirmed TB. This was also found by the ISG in 2007 when using their model. The delay before culling benefit became apparent was about 5 years after the first substantial cull. This has implications for the culls which started in South West England in 2013. If account is taken for the need to average the data, the number of years needed to see TB drop, and the reporting delay, it may not be until September 2023 before the impact of these culls become clear. Also, if culls stop after year four in each zone, this risks benefits falling short of those achieved in the RBCT.

scholarly journals The prevalence, distribution and severity of detectable pathological lesions in badgers naturally infected with Mycobacterium bovis

2007 ◽  
Vol 136 (10) ◽  
pp. 1350-1361 ◽  
Author(s):  
H. E. JENKINS ◽  
W. I. MORRISON ◽  
D. R. COX ◽  
C. A. DONNELLY ◽  
W. T. JOHNSTON ◽  
...  
Keyword(s):  
Respiratory Tract ◽  
Mycobacterium Bovis ◽  
Bovine Tuberculosis ◽  
Lower Prevalence ◽  
Large Sample ◽  
Pathological Lesions ◽  
Badger Culling ◽  
Severe Pathology ◽  
Bite Wounds ◽  
The Impact

SUMMARYThe Randomized Badger Culling Trial (RBCT) began in 1998 to determine the impact of badger culling in controlling bovine tuberculosis in cattle. A total of 1166 badgers (14% of total) proactively culled during the RBCT were found to be tuberculous, offering a unique opportunity to study the pathology caused by Mycobacterium bovis in a large sample of badgers. Of these, 39% of adults (~6% of all adults culled) had visible lesions (detectable at necropsy) of bovine tuberculosis; cubs had a lower prevalence of infection (9%) but a higher percentage of tuberculous cubs (55·5%) had visible lesions. Only ~1% of adult badgers had extensive, severe pathology. Tuberculous badgers with recorded bite wounds (~5%) had a higher prevalence of visible lesions and a different distribution of lesions, suggesting transmission via bite wounds. However, the predominance of lesions in the respiratory tract indicates that most transmission occurs by the respiratory route.

scholarly journals The occurrence of Mycobacterium bovis infection in cattle in and around an area subject to extensive badger (Meles meles) control

1995 ◽  
Vol 114 (1) ◽  
pp. 179-193 ◽  
Author(s):  
R. S. Clifton-Hadley ◽  
J. W. Wilesmith ◽  
M. S. Richards ◽  
P. Upton ◽  
S. Johnston
Keyword(s):  
Mycobacterium Bovis ◽  
Proportional Hazards ◽  
Meles Meles ◽  
The Other ◽  
Small Scale ◽  
Total Clearance ◽  
Proportional Hazards Regression ◽  
South West ◽  
Cattle Herds ◽  
South West England

SUMMARYThe occurrence of Mycobacterium bovis infection in cattle herds during the period 1966–92 in two geographically related areas in South-West England is compared. In one area comprising 104 km2 all badgers were systematically destroyed from 1975–81, after which recolonization was allowed; in the other, comprising 116 km2, small scale, statutory badger removal operations were undertaken from 1975 onwards where specific herds were detected with M. bovis infection. In the area with total clearance, no further incidents with M. bovis isolation occurred from 1982–92. Survival analysis and proportional hazards regression indicated that the risk of herds being identified with infection was less once badgers had been cleared from their neighbourhood, whereas it was greater in herds with 50 or more animals, and once cattle in a herd had responded positively to the tuberculin skin test, even though infection with M. bovis was not confirmed subsequently. The study provides further evidence that badgers represent an important reservoir of M. bovis infection for cattle and that badger control is effective in reducing incidents of cattle infection with M. bovis if action is thorough and recolonization is prevented.

scholarly journals Aspects of the epidemiology of bovine tuberculosis in badgers and cattle. I. The prevalence of infection in two wild animal populations in south-west England

1981 ◽  
Vol 86 (3) ◽  
pp. 237-245 ◽  
Author(s):  
P. A. Barrow ◽  
J. Gallagher
Keyword(s):  
Lymph Node ◽  
Bovine Tuberculosis ◽  
Mammalian Species ◽  
Wild Animal ◽  
Wild Animals ◽  
South West ◽  
Animal Populations ◽  
On Farm ◽  
Two Populations ◽  
South West England

SUMMARYThe prevalence of infections caused by Mycobacterium bovis was estimated in two populations of wild animals in the south west of England. A variety of mammalian species was trapped on farm land where incidents of infection with tuberculosis had occurred in cattle. Bacteriological analysis of lymph node samples and lesions showed that the only animals acting as a reservoir for M. bovis were badgers. Examination of arthropod ectoparasites of infected badgers proved negative for M. bovis and suggests that these are unlikely to act as vectors in transmission of the disease.

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