Bovine TB

Addlestone, United Kingdom

Bovine TB

Addlestone, United Kingdom
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Heat- and motion-activated camera-traps were used to document badger presence in Northern Scotland. Credit: Kerry Kilshaw / WildCRU In a new study researchers have found that although warmer weather should benefit badger populations, the predicted human population increase in the Scottish highlands is likely to disturb badgers and counteract that effect. These results emphasise the importance of interactive effects and context-dependent responses when planning conservation management under human-induced rapid environmental change. The new findings, published in the scientific journal Diversity and Distributions, result from a collaboration between researchers from Uppsala University in Sweden and Oxford's Wildlife Conservation Research Unit. Building on data from 168 camera trap stations actually collected originally to look at Scottish wildcat distributions, the team was also able to detect local badger (Meles meles) presence and absence. They found that different factors, such as weather conditions, land cover type and human disturbance interact to determine which locations badgers choose to populate across the Scottish Highlands. Overall, badger occupancy was more likely at sites with higher minimum winter temperature and lower elevation. But when study areas of similar temperature and elevation were grouped together, more complex patterns emerged. Specifically, in less favourable cooler upland areas badger occupancy was associated with higher availability of agricultural patches, possibly due to the additional food resources they provide. This pattern was, however, not found in warmer lowland areas. These lowland areas typically provide more favourable foraging conditions, but also include more human infrastructures (farms, roads, villages, etc) that constrained badger occurrence; badgers were more often found further away from settlements and roads. While medium estimates of a 1-3°C increase in mean minimum winter temperature for Northern Scotland by the 2050s would lead to better conditions for badgers in Highland Scotland, forecasts based on this factor alone are likely to prove simplistic and naïve. Disturbances associated with a predicted parallel 5% increase in human population in the Scottish Highlands by 2037 may counteract the benefits of increasing temperatures. It may therefore prove faulty or superficial to assume that species will simply benefit from warming conditions along the former cold-edge of their distribution if other environmental factors are not considered. Explore further: Bovine TB infection depends on feedback between cattle and badgers More information: André P. Silva et al, Climate and anthropogenic factors determine site occupancy in Scotland's Northern-range badger population: implications of context-dependent responses under environmental change, Diversity and Distributions (2017). DOI: 10.1111/ddi.12564


News Article | September 12, 2017
Site: www.sciencemag.org

The United Kingdom will triple the number of badgers killed in its campaign to eradicate a strain of tuberculosis (TB) that strikes cattle. As many as 33,841 badgers could be shot over the next year, the Department for Environment, Food and Rural Affairs announced yesterday. Wildlife advocates are upset at the increased slaughter, and scientists are skeptical about the chances of success. “It is deeply disappointing,” said Rosie Woodroffe, an ecologist with the Zoological Society of London. Bovine TB has been spreading for 2 decades in the United Kingdom, and England has the highest incidence in Europe. There is no threat to human health, because pasteurization kills the bacteria in milk. Cattle herds are regularly checked for the disease, and when infections are detected, the herd must be slaughtered. Last year the toll reached 29,000 animals. The disease enters herds through the shipping of undiagnosed cattle, and from badgers, which are the main reservoir of the disease in wildlife. The government’s 25-year strategy to eradicate bovine TB relies on restricting transport of cattle from disease hot spots and vaccinating or killing badgers. Badger culls began in 2013 in Somerset and Gloucestershire, and now cover 10 areas. Eleven more areas are being added now, each covering an average of 489 square kilometers. A preliminary analysis of the first 2 years of culling, reported last month in Ecology and Evolution, cautioned that the data were limited and it would be “unwise” to generalize about how effective the policy has been so far. Badger culling is a double-edged tool, according to an 8-year experiment that began in 1998. When done effectively, it can reduce bovine TB inside the control zone, but incidence is likely to increase up to 2 kilometers outside. That appears to be because some badgers leave the control zone, as a result of disruption to their social groups, and spread the disease. Tim Coulson, a zoologist at the University of Oxford in the United Kingdom, participated in the independent expert panel that the oversaw the experiment. He calls the expanded cull “contrary to scientific understanding.” The trial culls showed the difficulty of achieving the necessary 70% reduction in badger population needed to reduce the risk of spreading disease to cattle. “My interpretation of this policy is that the government thinks it is better to be seen to be doing something, rather than to do nothing at all—even if it risks making the problem worse.” The U.K. government’s chief veterinarian, Nigel Gibbens, yesterday called the culls “the best available option” for controlling the disease and said they should be rolled out to more of the country. Vaccination of badgers will begin again in 2018, after a 2-year pause due to a vaccine shortage, farming minister George Eustice said.


Researchers from the College of Veterinary Medicine, Northwest A&F University in Shaanxi, China claim they have successfully genetically modified cows to be resistant to bovine tuberculosis. Bovine tuberculosis is an infectious disease caused by the Mycobacterium bovis bacteria. It can also spread to and affect other mammals, including deer, goats, pigs, cats, dogs, and humans. In cattle, bovine tuberculosis has the characteristics of a respiratory disease, causing weight loss, cough, and fever in severe cases. It is mostly asymptomatic, although evidence of infection can be seen in the lymph glands, throat, or lungs of the animal. Bovine TB can spread from cattle to cattle through exposure to breath or discharges from the infected animal's mouth or nose, consumption of infected milk, before birth through the placenta, and indirectly via environmental contamination. Using an advanced technique called clustered regularly interspaced short palindromic repeats (CRISPR, pronounced crisper), or more specifically, the CRISPR-Cas9 system, a genome editing tool, the scientists inserted a gene linked to tuberculosis resistance into 20 cattle. Results show that 11 of the genetically modified cows lived beyond the age of 3 months and were more resistant to the disease compared to their non-genetically modified counterparts. The researchers didn't note any side effects in the animals as a consequence of genetic modification. The full study was published online on Jan. 31 in the journal Genome Biology. With this new development and the use of the CRISPR/Cas9 system, the authors are hopeful that their study will be valuable for agricultural applications. Many developing countries have resorted to slaughtering thousands of infected cattle annually to put an end to bovine TB, but to no avail. More than 26,000 cattle were reportedly slaughtered in the UK back in 2013, costing taxpayers at least £100 million or more than $120 million. "I think this is a very neat study that demonstrates the feasibility of introducing a desired gene of interest via a potentially safer way," Suk See De Ravin, a researcher with the Laboratory of Host Defenses, under the U.S. National Institutes of Allergy and Infectious Diseases, remarked. De Ravin, who is not part of the study, also noted that this new information may be the key to raising animals with a robust resistance against diseases and may potentially pave the way to reducing or even eliminating the excessive use of antibiotics in livestock, which has its negative effects on human health, too. However, some experts think otherwise. "Although it is a thorough and novel paper on using gene technology in transgenic cattle at this stage I doubt if the research will have any application to prevention of TB in cattle using transgenic technology," Ian McConnell, emeritus professor of veterinary science at the University of Cambridge, told the BBC, adding that TB in cattle is more complicated than we can imagine. © 2017 Tech Times, All rights reserved. Do not reproduce without permission.


Dean G.,Bovine TB | Whelan A.,Bovine TB | Whelan A.,UK Defence Science and Technology Laboratory | Clifford D.,Bovine TB | And 7 more authors.
Vaccine | Year: 2014

There is a requirement for vaccines or vaccination strategies that confer better protection against TB than the current live attenuated Mycobacterium bovis Bacillus Calmette-Guerin (BCG) vaccine for use in cattle. Boosting with recombinant viral vectors expressing mycobacterial proteins, such as Ag85A, has shown a degree of promise as a strategy for improving on the protection afforded by BCG. Experiments in small animal models have indicated that broadening the immune response to include mycobacterial antigens other than Ag85A, such as Rv0288, induced by boosting with Ad5 constructs has a direct effect on the protection afforded against TB. Here, we compared the immunogenicity and protection against challenge with M. bovis afforded by boosting BCG-vaccinated cattle with a human type 5 (Ad5)-based vaccine expressing the mycobacterial antigens Ag85A (Ad5-85A); or Ag85A, Rv0251, Rv0287 and Rv0288 (Ad5-TBF); or with protein TBF emulsified in adjuvant (Adj-TBF). Boosting with TBF broaden the immune response. The kinetics of Ad5-TBF and Adj-TBF were shown to be different, with effector T cell responses from the latter developing more slowly but being more durable than those induced by Ad5-TBF. No increase in protection compared to BCG alone was afforded by Ad5-TBF or Adj-TBF by gross pathology or bacteriology. Using histopathology, as a novel parameter of protection, we show that boosting BCG vaccinated cattle with Ad5-85A induced significantly better protection than BCG alone. © 2013.


Villarreal-Ramos B.,Bovine TB | Berg S.,Bovine TB | Chamberlain L.,Bovine TB | McShane H.,Roosevelt University | And 3 more authors.
Vaccine | Year: 2014

Vaccination is being considered as part of a sustainable strategy for the control of bovine tuberculosis (BTB) in the UK. The live attenuated Mycobacterium bovis bacillus Calmette-Guerin (BCG) has been used experimentally to vaccinate cattle against BTB. However, BCG confers partial protection against BTB and therefore, there is a need to develop improved vaccines. BTB vaccine efficacy experiments require the use of biosafety level 3 facilities which are expensive to maintain, generally oversubscribed and represent a bottle neck for the testing of vaccine candidates. One indicator of the induction of protective responses would be the ability of the host's immune response to control/kill mycobacteria. In this work we have evaluated an intranodal BCG challenge for the selection of vaccine candidates at biosafety level 2 which are capable of inducing mycobactericidal responses. To our knowledge, this is the first such report. Whilst BCG only confers partial protection, it is still the standard against which other vaccines are judged. Therefore we tested the BCG intranodal challenge in BCG (Danish strain) vaccinated cattle and showed that vaccinated cattle had lower BCG cfu counts than naïve cattle at 14 and 21 days after intranodal challenge with BCG (Tokyo strain). This model could help prioritize competing TB vaccine candidates and exploration of primary and secondary immune responses to mycobacteria. Crown Copyright © 2014.


PubMed | Bovine TB and Roosevelt University
Type: Journal Article | Journal: Veterinary immunology and immunopathology | Year: 2014

BCG is used experimentally as a vaccine against tuberculosis (TB), induced by Mycobacterium bovis, in cattle (bTB). However, the efficacy of BCG is variable in humans, cattle and guinea pigs. An adenoviral vector expressing Antigen 85A (Ad5Ag85A) has enhanced protection against TB in mice when used in combination with BCG for prime-boost experiments. However, the route of immunisation affects the degree of protection seen. This work examines the immunogenicity of a new vectored vaccine (Ad5-TBF) that expresses Ag85A, Rv0287, Rv0288 and Rv0251c to explore the effects of dose of adenoviral boost and route of inoculation on immunogenicity. We found that 210(9) infectious units (iu) delivered intradermally conferred the most consistent and strongest responses of the different regimes tested.


PubMed | McMaster University, Bovine TB and Roosevelt University
Type: Comparative Study | Journal: Vaccine | Year: 2014

There is a requirement for vaccines or vaccination strategies that confer better protection against TB than the current live attenuated Mycobacterium bovis Bacillus Calmette-Guerin (BCG) vaccine for use in cattle. Boosting with recombinant viral vectors expressing mycobacterial proteins, such as Ag85A, has shown a degree of promise as a strategy for improving on the protection afforded by BCG. Experiments in small animal models have indicated that broadening the immune response to include mycobacterial antigens other than Ag85A, such as Rv0288, induced by boosting with Ad5 constructs has a direct effect on the protection afforded against TB. Here, we compared the immunogenicity and protection against challenge with M. bovis afforded by boosting BCG-vaccinated cattle with a human type 5 (Ad5)-based vaccine expressing the mycobacterial antigens Ag85A (Ad5-85A); or Ag85A, Rv0251, Rv0287 and Rv0288 (Ad5-TBF); or with protein TBF emulsified in adjuvant (Adj-TBF). Boosting with TBF broaden the immune response. The kinetics of Ad5-TBF and Adj-TBF were shown to be different, with effector T cell responses from the latter developing more slowly but being more durable than those induced by Ad5-TBF. No increase in protection compared to BCG alone was afforded by Ad5-TBF or Adj-TBF by gross pathology or bacteriology. Using histopathology, as a novel parameter of protection, we show that boosting BCG vaccinated cattle with Ad5-85A induced significantly better protection than BCG alone.


PubMed | Bovine TB and Roosevelt University
Type: Journal Article | Journal: Vaccine | Year: 2014

Vaccination is being considered as part of a sustainable strategy for the control of bovine tuberculosis (BTB) in the UK. The live attenuated Mycobacterium bovis bacillus Calmette-Guerin (BCG) has been used experimentally to vaccinate cattle against BTB. However, BCG confers partial protection against BTB and therefore, there is a need to develop improved vaccines. BTB vaccine efficacy experiments require the use of biosafety level 3 facilities which are expensive to maintain, generally oversubscribed and represent a bottle neck for the testing of vaccine candidates. One indicator of the induction of protective responses would be the ability of the hosts immune response to control/kill mycobacteria. In this work we have evaluated an intranodal BCG challenge for the selection of vaccine candidates at biosafety level 2 which are capable of inducing mycobactericidal responses. To our knowledge, this is the first such report. Whilst BCG only confers partial protection, it is still the standard against which other vaccines are judged. Therefore we tested the BCG intranodal challenge in BCG (Danish strain) vaccinated cattle and showed that vaccinated cattle had lower BCG cfu counts than nave cattle at 14 and 21 days after intranodal challenge with BCG (Tokyo strain). This model could help prioritize competing TB vaccine candidates and exploration of primary and secondary immune responses to mycobacteria.

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