Roadmap for development of disease control strategies for bTB

What are we trying to achieve and why? What is the problem we are trying to solve?

• The control and ultimate elimination of TB infection at a herd, regional and national level (in the EU to below threshold).
• Prevention of transmission to humans.
• Preventing spread of pathogen resulting from the poor implementation of control measures.
• Manage and limit the within- and between-country trade implications of having TB.Limit the impact of TB on affected wildlife.
• Limit massive cattle herd culling

What are the scientific and technological challenges (knowledge gaps needing to be addressed)?

• Sensitive detection and elimination of infected and pathogen shedding animals; current tests lack sensitivity; current knowledge of different TB disease status in cattle is limited
• Prevention of spread through immunisation, elimination of Mb shedders culling at risk to transmit and improved biosecurity.
• Knowledge outreach – evidence of misinformation.
• Spillover/spillback involving other livestock, wildlife, and on occasion humans.
• Environmental survival to at least some extent.
• Evidence supporting both direct and indirect transmission routes but context dependent.
• Challenging to obtain compliance with biosecurity measures – difficult and expensive to undertake research to provide evidence of value.
• Prevention of infection requires very strong international collaboration and alignment of approaches – should it be reinforced?
• Diversity of local contexts where control needs to be implemented.
• Engagement of all stakeholders who determine control strategy inputs (regulators, cattle industry) and are affected by outcomes.
• Disease control tends to be managed under statute – creates challenges regarding cost and responsibility sharing.
• Consideration of varied restraints/concerns: breeds, value, environment, social concerns, food security, cost, supplies.
• Outcome of exposure/infection determined by host factors (including genetic predisposition, inflammatory response etc.), pathogen factors (including dose and route) and “environmental” risks, including concurrent infection(s), malnutrition, pregnancy, stress, reservoirs for Mb survival (water, amoebae) etc.
• Current immunological tests index prior “exposure”, not necessarily infection and infectivity.

What approaches could/should be taken to address the research question?

• Probably no single “magic bullet” for TB control; requires “marginal gains” and a package of control measures across all relevant sources.
• Routine, sensitive testing to pick up infected animals before transmission occurs. Prevention is better than cure – important to keep TB out of herd – difficult to remove.
• Reduction of spread through reduced susceptibility (immunisation and/or genetic selection refer).
• Reduction of spread through improved biosecurity.
• Owner cooperation through establishing cost and benefits of control.
• Risk factor studies in sporadic, recurrent, and persistent TB herds
• Identification of shedders to go towards bTB control at the level of the individual and not the herd (limit massive herd culling)
• Knowledge outreach – communicate evidence from modelling
  and transmission dynamics studies.
• Consider Cattle Health Certification Standards (or equivalent)
  certification/accreditation, if available.
• Develop robust, repeatable methods to speed up generation of
  pathogen genomic data for epidemiological inference and source tracing.

What else needs to be done before we can solve this need?

• That control strategies are communicated and accepted, cost effective and don’t cripple producers.
• That the strategy is acceptable to key stakeholders, especially producers.
• The availability of sensitive diagnostic tests.
• The availability and market authorisation of acceptable, effective DIVA vaccines to prevent infection, progression, and/or the onward transmission of infection.
• Encourage stakeholder uptake of genetic/genomic selection to reduce TB susceptibility where available; reassure stakeholders of lack of antagonisms with other desirable breeding goals.
• Detailed knowledge of the source of infection and transmission pathways.
• Animal-level database recording location, tests, and movements.
• Animal level of clinical status and Mb shedding risk
  Detailed maps of farm locations and fragmentation, rented
  grazing etc.

Existing knowledge including successes and failures