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Bovine Tuberculosis

Volume 475: debated on Thursday 15 May 2008

To ask the Secretary of State for Environment, Food and Rural Affairs what recent research he has commissioned into the relationship between tuberculosis in animals and human strains of the disease. (204955)

DEFRA has not commissioned any recent research into the relationship between bovine TB in animals and TB in humans. The risk of humans contracting Mycobacterium bovis (M. bovis) infection from cattle in Great Britain is considered low due to robust human health controls (cattle surveillance and slaughter of infected animals; controls on milk and meat; occupational health controls; and Government Departments and agencies working together to monitor the situation). The majority of cases of tuberculosis in humans are caused by a different organism, Mycobacterium tuberculosis.

At present, less than 1 per cent. of all confirmed cases of TB in humans are due to infection with M. bovis. In these cases, the Health Protection Agency carries out epidemiological investigations into the source and route of transmission of the infection. Most M. bovis infections identified in Britain in the present day have been picked up abroad or prior to the introduction of widespread pasteurisation of milk.

DEFRA monitors all cases of M. bovis in humans to assess the implications for animal health controls.

To ask the Secretary of State for Environment, Food and Rural Affairs what evidence he has considered on the relationship between the size of herds and the incidence of bovine tuberculosis in cattle. (204956)

We have considered a range of evidence relating to risk factors which may increase the likelihood of TB in cattle herds. An association between increased herd size and an increased risk of TB herd breakdown, and persistence of infection, has been reported by several recent studies in the scientific literature. However, the relationship is not straightforward. Testing more animals is likely to result in an increased probability of obtaining a positive test result in the herd, and herd size may be a proxy for other management-related risk factors such as herd turnover rates and stocking density, farm enterprise factors, and risks from foodstuffs.