Wild Deer TB Surveillance 2008/2009

The TB Core Stakeholder Working Group has recommended a holistic approach to eradication of Bovine Tuberculosis. There are three strands to the holistic approach: active involvement of stakeholders, addressing bovine transmission, and addressing the wildlife factor. Among the actions to address the wildlife factor considered by the Group was to carry out surveillance of TB in wild deer. On 9 December 2008 the Minister for Agriculture and Rural Development announced to the Assembly that, among a number of actions DARD would be taking in relation to Bovine Tuberculosis, surveillance of TB in wild deer was to be an early action.

The 2008/2009 deer TB surveillance exercise started on 30 December 2008. Collection of samples from female deer was completed by 28 February 2009. Collection of samples from male deer was completed on 7 March 2009. In total 146 deer were sampled. Final laboratory results were available in September 2009.

Samples were collected from six wild deer populations in which evidence or suspicion of TB had been reported in the 1990s. Samples were collected from wild deer populations in Antrim, Down, Fermanagh, Londonderry and Tyrone.

Tonsils, retropharyngeal lymph nodes, submandibular lymph nodes, parotid lymph nodes, mediastinal lymph nodes, bronchial lymph nodes and mesenteric lymph nodes were collected.

The Agri-Food and Biosciences Institute carried out histological examination and culturing.

Mycobacterium bovis was isolated from three deer in three separate wild deer populations. There were also two Mycobacterium avium isolates and one Mycobacterium palustre isolate.

The prevalence of M. bovis in wild deer recorded in this surveillance exercise was low at 2%. This prevalence level is consistent with recent surveys of wild deer in England and Wales. However, the sample size in this surveillance exercise was small.

Such wild deer TB surveillance helps us to understand the role of wild deer in the epidemiology of TB.