Sir

In their Correspondence, Paul Torgerson and David Torgerson question the importance of controlling bovine tuberculosis (TB) in the United Kingdom ('Does risk to humans justify high cost of fighting bovine TB?' Nature 455, 1029; 2008). However, they disregard the crucial role of disease control in protecting international trade — a key reason why the UK government is trying to eradicate bovine TB.

To be exported from the United Kingdom, cattle aged 42 days or older must have tested negative for bovine TB within the previous 30 days. In 1995, the value of live cattle exports was £77.6 million (US$115 million); after the imposition of the ban on exports because of BSE (bovine spongiform encephalopathy), this fell to zero (see http://tinyurl.com/6j8o2w). Although the ban on exports from the United Kingdom was lifted in 2006, live cattle exports are only just now starting to recover.

To stop control of bovine TB would once again block all live exports. UK government expenditure on the foot-and-mouth disease outbreak in 2001 was £2.79 billion, and the protection of international trade was a key driver of the control measures used at that time (see http://tinyurl.com/67p9g5).

The protection of trade status is one aspect of an integrated policy for controlling bovine TB that safeguards public health and the agricultural economy as well as animal health and welfare. Indeed, as we face an increasing problem with bovine TB in the United Kingdom, the success of this control strategy in protecting public health is evidenced by the sporadic nature of Mycobacterium bovis infections in the human population (see A. L. Gibson et al. J. Clin Microbiol. 42, 431–434; 2004; J. T. Evans et al. Lancet 369, 1270–1276; 2007). Now is not the time to dismantle controls for bovine TB.

See also Bovine TB: don't get rid of the cat because the mice have gone