bTB now affecting sheep
MARCH 19, 2010: Concerns that bovine TB (bTB) is becoming more prevalent in species other than cattle and badgers have neen heightened by the discovery of the disease in sheep and wild boar.
But there is also some encouraging news with bTB in the national cattle herd showing a fall during 2009, following the record levels seen in 2008, latest Defra figures show. Provisional statistics published on Wednesday (March 17) showed an 8.8 per cent decrease in the number of new TB incidents in cattle from 5,012 in 2008 to 4,572 in 2009. With more herds tested in 2009, this equates to a provisional 14 per cent decrease in the TB incidence rate � new incidents as a proportion of tests on unrestricted herds. Herds under restriction, however, due to a TB incident increased to 8,396 in 2009, from just under 8,000 in 2008, a figure that takes long-term persistent outbreaks into account. Details of the number of cattle slaughtered in 2009 are not yet available. A further sign of the extent to which the disease is taking hold in parts of the country emerged when a flock of Lleyn sheep in Gloucestershire were placed under TB restriction. Vets were alerted by chronic weight loss in 20 of 220 ewes and one ram. Post-mortem findings in three of the six sheep were consistent with TB and M. bovis spoligotype 10, the predominant strain in local cattle herds and wildlife, was isolated. Lesions in these three sheep were extensive, a letter in the Veterinary Record reports. A Defra spokesman said the movement restrictions would only be lifted when Animal Health was confident the flock is free from TB. He said M. bovis in sheep was ‘considered rare’. The Department has also revealed ‘lesions consistent with TB’ have been identified in a feral wild boar in the Ross-on-Wye area during post-mortem examination. Defra figures show there were more than 140 bTB cases identified in individual animals other than cattle in 2009, including in 68 alpacas, 26 cats, 23 pigs and five sheep. The true numbers are almost certainly much higher as there is no active surveillance in non-bovine species. Defra said most other species ‘generally act only as spill-over hosts’ from cattle and badgers with disease not sustained within populations without an external source of infection. National Sheep Association chief executive Peter Morris said cases in sheep were not unexpected and the industry was not required to take additional actions.