10.1136/vr.c6880 | Veterinary Record | 1 of 6 Papers Papers Tuberculosis in goats on a farm in Ireland: epidemiological investigation and control A. Shanahan, M. Good, A. Duignan, T. Curtin, S. J. More This paper describes an outbreak of tuberculosis (TB) caused by Mycobacterium bovis in a dairy goat herd on a farm in Ireland, where 66.3 per cent of the herd tested positive to the single intradermal comparative tuberculin test (SICTT) at initial detection. An epidemiological investigation was conducted to determine the origin of the outbreak, considering issues such as animal movements and herd management practices. Infection was introduced with a consignment of goats, as determined by the variable number tandem repeat profile. Infection was eradicated using a test and cull programme involving the SICTT, the interferon-γ assay and a multiplex immunoassay (Enferplex TB). IN Ireland, the control of tuberculosis (TB), which is caused by Mycobacterium bovis, is well documented. An eradication programme for cattle was established in 1954 and the annual animal incidence now remains relatively stable, at approximately 0.4 per cent. Endemic infection in badgers (Meles meles), is a key impediment to eradication (More and Good 2006). M bovis infection occurs in many domestic, feral and exotic animals, including goats and sheep, and in human beings (O’Reilly and Daborn 1995). Cousins and others (1993) and Cousins (2001) cautioned that investigations should consider other in- contact domestic animals when TB has been confirmed in cattle. This has particular significance in cases where infected cattle and goats are kept on the same holding. TB in goats can lead to generalised progressive disease with clini- cal signs such as respiratory disease, hoarse cough, weight loss and decreased milk production (Bernabé and others 1991). Infection in goats has been diagnosed in many countries, including South Africa (van den Heever 1984), unspecified African states (Ayele and others 2004), Russia (Kel’dybaev and Turkebaeva 1969), Australia (Cousins and others 1993), New Zealand (Coleman and Cooke 2001), France (Thorel 1980), Germany (Honeker 1951a, b), Spain (Alvarez and oth- ers 2008), the UK (Daniel and others 2009) and Brazil (Pignata and others 2009). TB in goats has previously been diagnosed at postmor- tem examination in Ireland (Department of Agriculture, Fisheries and Food [DAFF], unpublished observations). EU Regulations (European Commission 2004a) require a TB con- trol plan, approved by the national competent authority, for milking goats/sheep or other non-bovine species. Food business operators pro- ducing or collecting raw milk from species susceptible to TB (including A. Shanahan, MVB, Department of Agriculture, Fisheries and Food, District Veterinary Office, Farnham Street, Cavan, Ireland M. Good, MVB, MRCVS, A. Duignan, MVB, MRCVS, Department of Agriculture, Fisheries and Food, Agriculture House, Kildare Street, Dublin 2, Ireland T. Curtin, MVB, MRCVS, Department of Agriculture, Fisheries and Food, District Veterinary Office, South Mall, Cork, Ireland S. J. More, BVSc, PhD, FACVSc, MVB, DipECVPH, DipECBHM, Centre for Veterinary Epidemiology and Risk Analysis, School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland Correspondence to: Ms Good, e-mail: margaret.good@agriculture.gov.ie Provenance: not commissioned; externally peer reviewed Veterinary Record doi: 10.1136/vr.c6880 goats) must ensure that it comes from herds regularly checked for TB under a control plan approved by the competent authority (ie, DAFF). This plan seeks first to establish the baseline status of any presence of infection with M bovis in the dairy goat/sheep herd by the use of the single intradermal comparative tuberculin test (SICTT) on all adults. Follow-up monitoring is conducted through further field testing (fur- ther biannual SICTT), complete postmortem examination of any goats presenting with clinical signs of TB and ongoing abattoir examination (with associated histopathology/microbiology of adult cull animals). In determining the frequency, section and percentage of the herd to be subjected to SICTT, other factors such as the husbandry (including outdoor access) and possible contact with other M bovis-susceptible spe- cies, including cattle and badgers, are also taken into consideration. All herds with cattle on the same holding are subjected to annual SICTTs. Since autumn 2008, all Irish goat herds supplying raw milk to an Irish food business operator must have a TB control plan. The Irish 2008 sheep and goat census (DAFF 2008) records 7279 goats in 383 herds, with the majority of the herds (86 per cent) holding 20 goats or fewer. Many owners use goat products for personal con- sumption only or are hobbyists. Thirty herds had more than 50 goats, including 28 that supplied milk (2008/09). In the 12 months from mid- 2008, approximately 5800 goats were tested as required to establish TB status under the control plan. TB was diagnosed in three herds, includ- ing two (farms A and C) that are discussed in detail in this paper. This paper presents an investigation to determine and describe the source of an outbreak of M bovis infection in a newly established milking goat herd in Ireland and the use of test and cull procedures in the eradication of the infection. Materials and methods Epidemiological investigation An epidemiological investigation to determine the source and poten- tial for within-herd transmission was conducted by evaluating both the goat herd (housing, feeding, husbandry, preventive health pro- gramme, goat movements) and the farm (the integrity of the farm boundary, other susceptible species and opportunities for cross-species contact). Relevant history, including details of herd mortality and mor- bidity, were established. A qualitative assessment was undertaken to determine the risk of introduction of M bovis infection and/or onward transmission, based on evaluation of inward movements to, and biose- curity practices on, the farm; TB prevalence in the locality; and the likelihood of within-herd infection spread. Further assessments and control measures to minimise the potential for within-herd transmis- sion were implemented based on diagnostic test results as they became available. group.bmj.com on September 11, 2016 - Published by http://veterinaryrecord.bmj.com/ Downloaded from