Pest management is by far the largest component of the TBfree programme. Operations are designed to reduce the number of pests (defined as vectors) that carry and spread TB to farmed livestock. Research demonstrates that possums are the main disease vectors of TB in New Zealand and they are the primary focus of control operations.

Eradication of TB is achieved by reducing the possum density to a very low and even level (about one possum per 10 hectares) for a period of at least five years. This low density means the disease is unable to be maintained within possum populations and will subsequently disappear from both possums and other wildlife.

An important aspect of the TBfree programme is surveying wildlife to identify and detect whether TB remains. OSPRI undertake this by trapping or culling possums and other sentinel species, such as pigs and ferrets, followed by post-mortem examination and analysis. This is done primarily in areas where we believe TB has been eradicated. The results are used to help determine whether freedom from TB within designated areas has been achieved. We expect to find minimal numbers of possums or other wildlife infected with TB from these surveillance activities, as significant possum control effort has already been undertaken. 

Possum control planning is guided by surveys to detect TB in possums and other wildlife hosts such as wild pigs, ferrets and deer. Surveys are also used to help measure progress towards eradication of TB using a Proof of Freedom (POF) framework, in which data is compiled on:

• Possum control history
• Possum population density measures
• Surveys for the presence or absence of TB in possums and other wildlife
• Results from TB tests of any cattle or deer herds in the vicinity.

This data is analysed to provide a statistical estimate of the probability that the possum population is free of TB. The calculated probability is used to guide any further possum control and wildlife surveillance activities that may be needed in the area. If the probability of TB freedom in possums is low, further control is carried out. At higher freedom probabilities, control is replaced by wildlife disease surveys until there is reasonable certainty that TB is no longer present and active management can safely be ceased. Over time, TB testing in livestock may also be wound down, with inspection of carcasses at slaughter providing to the required pre-and post mortem surveillance and monitoring required to detect any recurrent or residual infection.

Find out more in our Controlling pests to eradicate TB factsheet.

Pest management under the TB Plan will be delivered through a framework of over 100 Tuberculosis Management Areas (TMAs) according to disease patterns, geographical features, control history, and future control needs. This will enable possum control and wildlife disease surveys to be planned and contracted in an efficient manner, and will provide a local focus for communications and consultation with land  occupiers, communities and groups interested in or affected by our operations. Each TMA will have an approximate planned target date for eradication.

Find out more about TMAs.