Testing of a palatable bait and compatible vaccine carrier for the oral vaccination of European badgers (Meles meles) against tuberculosis

Gowtage, Sonya; Williams, Gareth; Henderson, Ray; Aylett, Paul; MacMorran, Duncan; Palmer, Si; Robertson, Andy; Lesellier, Sandrine; Carter, Stephen P.; Chambers, Mark A.

doi:10.1016/j.vaccine.2016.12.004

Cited by 16 publications

(25 citation statements)

References 11 publications

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“…Both the UK and Ireland are investigating parenteral and oral vaccine strategies designed to inoculate badgers against M . bovis [ 11 – 13 ]. However, to understand the dynamics of a disease and to control it successfully, a complete picture of the ecology and ranging behaviour of the carrier species is required [ 1 ].…”

Section: Introductionmentioning

confidence: 99%

Super-ranging. A new ranging strategy in European badgers

et al. 2018

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We monitored the ranging of a wild European badger (Meles meles) population over 7 years using GPS tracking collars. Badger range sizes varied seasonally and reached their maximum in June, July and August. We analysed the summer ranging behaviour, using 83 home range estimates from 48 individuals over 6974 collar-nights. We found that while most adult badgers (males and females) remained within their own traditional social group boundaries, several male badgers (on average 22%) regularly ranged beyond these traditional boundaries. These adult males frequently ranged throughout two (or more) social group’s traditional territories and had extremely large home ranges. We therefore refer to them as super-rangers. While ranging across traditional boundaries has been recorded over short periods of time for extraterritorial mating and foraging forays, or for pre-dispersal exploration, the animals in this study maintained their super-ranges from 2 to 36 months. This study represents the first time such long-term extra-territorial ranging has been described for European badgers. Holding a super-range may confer an advantage in access to breeding females, but could also affect local interaction networks. In Ireland & the UK, badgers act as a wildlife reservoir for bovine tuberculosis (TB). Super-ranging may facilitate the spread of disease by increasing both direct interactions between conspecifics, particularly across social groups, and indirect interactions with cattle in their shared environment. Understanding super-ranging behaviour may both improve our understanding of tuberculosis epidemiology and inform future control strategies.

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Section: Introductionmentioning

confidence: 99%

Super-ranging. A new ranging strategy in European badgers

et al. 2018

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“…Whilst these initial results are instructive and encouraging, this study was not able to investigate inter-annual variation in uptake rates which will need to be considered in future work. Further studies are also required to evaluate the uptake of a bait formulation [ 16 ] that will ultimately be used to deliver BCG under different deployment scenarios. The eventual cost of an oral bait containing vaccine is currently unknown, but it is likely to be considerably more expensive than the surrogate bait used in the present study.…”

Section: Discussionmentioning

confidence: 99%

“…Since licensing of the vaccine in 2010 several thousand doses of BadgerBCG have been delivered (through live-trapping and injection) in England and Wales by government agencies, and by voluntary and community sector organisations (APHA unpublished data). However, as the delivery of BadgerBCG by cage-trapping and injection is labour intensive, there has been considerable investment in the development of a candidate oral bait for BCG delivery [ 16 – 18 ] which may offer a more cost-effective means of vaccinating badgers at a wider scale. The potential contribution of an oral vaccine to TB control was highlighted by a recent study which provided field evidence for a significant protective effect of oral BCG administration in a wild badger population [ 15 ].…”

Section: Introductionmentioning

confidence: 99%

Bait uptake by wild badgers and its implications for oral vaccination against tuberculosis

et al. 2018

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The deployment of baits containing vaccines or toxins has been used successfully in the management of wildlife populations, including for disease control. Optimisation of deployment strategies seeks to maximise uptake by the targeted population whilst ensuring cost-effectiveness. Tuberculosis (TB) caused by infection with Mycobacterium bovis affects a broad range of mammalian hosts across the globe, including cattle, wildlife and humans. The control of TB in cattle in the UK and Republic of Ireland is hampered by persistent infection in European badgers (Meles meles). The present study aimed to determine the best strategy for maximising uptake of an oral vaccine by wild badgers, using a surrogate novel bait deployed at 40 badger social groups. Baits contained a blood-borne biomarker (Iophenoxic Acid, IPA) in order to measure consumption in badgers subsequently cage trapped at targeted setts. Evidence for the consumption of bait was found in 83% (199/240) of captured badgers. The probability that badgers had consumed at least one bait (IPA >10 μg ml-1) was significantly higher following deployment in spring than in summer. Lower uptake amongst social groups where more badgers were captured, suggested competition for baits. The probability of bait consumption was significantly higher at groups where main and outlier setts were provided with baits than at those where outliers were present but not baited. Badgers captured 10–14 days post bait feeding had significantly higher levels of bait uptake compared to those caught 24–28 days later. Uptake rates did not vary significantly in relation to badger age and whether bait was placed above ground or down setts. This study suggests that high levels of bait uptake can be achieved in wild badger populations and identifies factors influencing the potential success of different deployment strategies. The implications for the development of an oral badger vaccine are discussed.

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“…BCG has been evaluated in numerous trials and in many different species since its creation, and although efficacy can be variable, it is generally considered an effective vaccine when administered parenterally, reviewed in [4]. However, delivery of BCG to mucosal surfaces through oral or intranasal administration is highly desirable to avoid the use of needles for humans and domesticated animals and to simplify immunisation of wildlife, particularly through presentation of BCG incorporated in bait [5].…”

Section: Introductionmentioning

confidence: 99%

“…The aim of the present study was to evaluate the potential of a BCG-Eudragit matrix formulation for oral vaccination against TB, with a focus on potential incorporation into bait for delivery to badgers [5]. We used Eudragit L100 supplied in powdered form.…”

Section: Introductionmentioning

confidence: 99%

In Vitro Evaluation of Eudragit Matrices for Oral Delivery of BCG Vaccine to Animals

Saleem¹,

Coombes

Chambers³

2019

Preprint

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Bacillus Calmette-Guérin (BCG) vaccine is the only licensed vaccine against tuberculosis (TB) in humans and animals. It is most commonly administered parenterally but oral delivery is highly advantageous for immunisation of cattle and wildlife hosts of TB in particular. Since BCG is susceptible to inactivation in the gut, vaccine formulations were prepared from suspensions of Eudragit L100 copolymer powder and BCG in PBS, containing Tween 80, with and without the addition of mannitol or trehalose. Samples were frozen at -20oC, freeze-dried and the lyophilised powders were compressed to produce BCG-Eudragit matrices. Production of the dried powders resulted in a reduction in BCG viability. Substantial losses in viability occurred at the initial formulation stage and at the stage of powder compaction. Data indicated that the Eudragit matrix protected BCG against simulated gastric fluid (SGF). The matrices remained intact in SGF and dissolved completely in SIF within three hours. The inclusion of mannitol or trehalose in the matrix provided additional protection to BCG during freeze-drying. Control needs to be exercised over BCG aggregation, freeze-drying and powder compaction conditions to minimise physical damage of the bacterial cell wall and maximise the viability of oral BCG vaccines prepared by dry powder compaction.

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Testing of a palatable bait and compatible vaccine carrier for the oral vaccination of European badgers (Meles meles) against tuberculosis

Cited by 16 publications

References 11 publications

Super-ranging. A new ranging strategy in European badgers

Super-ranging. A new ranging strategy in European badgers

Bait uptake by wild badgers and its implications for oral vaccination against tuberculosis

In Vitro Evaluation of Eudragit Matrices for Oral Delivery of BCG Vaccine to Animals

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