Bovine tuberculosis vaccine

Bovine tuberculosis has received much attention recently because of debate over how to deal with wild badgers that act as a reservoir for the disease. Trials of badgers culls are due to start shortly but this page explains about the development of vaccines and the importance of animal experiments to develop and test them.

Bovine tuberculosis has a huge economic impact with 29,7 million pounds spent yearly in the UK, as a consequence of the disease. It is the forth most expensive endemic infection to UK agriculture.

Developing the vaccine

In the 1910s, Albert Calmette and Camille Guérin developed a way of culturing the bovine tuberculosis bacillus, Mycobacterium bovis, that made it less virulent. By repeating this over several generations they produced a strain that was attenuated enough that it was unable to cause tuberculosis disease in research animals and therefore suitable for use in a vaccine. This became the Bacillus Calmette-Guerin (BCG) vaccine, developed thanks to animal testing and first given to humans in 1921.ANCHOR While very safe, it is a relatively ineffective vaccine with limited protection against adult forms of the disease. It is now only administered routinely in countries that are highly endemic for TB.

Vaccinating animals

The BCG vaccine has since been tested in brushtail possums, cattle and badgers to determine its ability to prevent infection in some cases, rather than just reducing the severity of symptoms.ANCHOR,ANCHOR,ANCHOR These animal experiments helped scientists to realise that BCG can be used to prevent infection rather than being limited to restricting the extent of the disease.

TB vaccines have been developed for cows, however these cause false positives in TB skin tests making it difficult to detect infected animals. It is not possible to vaccinate cows in the field under EU legislation and so research is done on experimentally infected cattle.ANCHOR

Badger vaccination could help reduce the prevalence and severity of bovine TB in a badger population, benefitting both badgers and cattle.

Initial tests to determine the safety of the badgerBCG vaccine required collaboration with researchers in the Republic of Ireland where a facility to house badgers under appropriate biological containment was built. This allowed the determination of a suitable dose of the vaccine.ANCHOR

Tests on badgers deliberately infected with TB were used to show that intramuscular administration was safe and as effective as subcutaneous delivery. This has the advantage of being more easily administered, without requiring the use of anaesthesia. Field trials and experimental infection studies were used to demonstrate that the intramuscular BCG vaccination reduces the progression, severity and excretion of M. bovis infection in badgers.ANCHOR,ANCHOR

Oral vaccines are currently in trials for use in badgers. The formulations used in these trials were developed for possums by researchers in New Zealand and this was all made possible thanks to animal testing.ANCHOR

• Animal(s): Cow, Other or unspecified mammals (non-rodent/non-primate)
• Countries: Ireland, New Zealand, United Kingdom
• Research field(s): Vaccine development
• Medical application(s): Vaccine, Veterinary

Last edited: 23 June 2015 15:04