A new study highlights that badger vaccination, in combination with the cattle test-and-removal programme, can reduce bovine tuberculosis (TB) but “may not be sufficient” to achieve eradication.
The study by You Chang of Wageningen University is funded by the Department of Agriculture, Food and the Marine’s (DAFM’s) Research Funding Programme.
It aims to assess the impact of badger vaccination, in addition to cattle test-and-removal and movement restriction.
In the assessment, transmission rate parameters and vaccination efficacy were estimated from a local cattle-badger transmission model, using infection data from the same trial.
Investigations were carried out into the contribution of several transmission mechanisms such as local cattle, residual infection, badgers and the introduction of cattle on the transmission of bTB at the level of both the individual and the herd.
To achieve the investigations, a metapopulation model (small populations) was created for the Co. Kilkenny badger vaccination trial area.
The model incorporates within-herd transmission for cattle and within-territory transmission for badgers, and also transmission between herds, both via cattle trade movements and via overlapping badger territories.
TB eradication
The results show that cattle-to-cattle transmission contributes most to new cattle infections at the individual animal (cattle) level. It shou that breakdowns at the herd level usually involve multiple routes.
As a result, the study recommends the need for a “multifaceted approach” for the TB eradication strategy.
It highlights the need for additional interventions that target cattle, badger, and movement to form a comprehensive intervention strategy, including cattle vaccination, improve farm biosecurity, badger vaccination and risk-based trading.
The researchers also suggested a strategy that simultaneously targets multiple transmission routes, including badgers, cattle and cattle movement.
An improved understanding of badger ecology and bTB epidemiology in other regions in Ireland was also recommended to enhance understandings.
Several countries, including Australia, the Netherlands and several northern European countries, have successfully eradicated bTB.
In Ireland, progress towards eradication progressed rapidly during the first decade of the eradication programme, with cattle incidence decreasing from 17 % in 1954 to 0.5 % in 1965.
In recent years, however, progress towards eradication has stalled, in part due to the presence of infected wildlife such as badgers.