YOUR readers should interpret the letter from Martin Hancox, and his long standing opinion (June 22) that super excreter infected cattle are the sole reservoir and mode of spread of bTB, with a degree of caution, as I am unaware of any evidence to support his hypothesis.

Taking his points one by one, firstly that cattle TB may be primarily a respiratory syndrome. We should remember that if left unchecked (which never happens now) it could spread to the udder. This is why all countries worldwide control bTB in cattle.

Second, I do not know the source of his data giving the incidence of bTB in badgers, but the SE 3032 report from Woodchester Park shows that 32 per cent of the 1,425 badgers examined over the period 2006 to 2010 were bTB positive on blood tests, and more than half of this group were culture positive and therefore potentially excreting infection.

Similarly the Krebs RBCT report Table 4.10 indicates for 1999 to 2005 around 20 per cent of badgers with bTB year on year.

This makes the comment by Mr Hancox that there is "little or no spread within badger populations" difficult to understand as infection is, unfortunately for the badger, becoming widespread.

In contrast, the DEFRA website reports that in Gloucestershire in 2014 there were 372,348 cattle tests performed with 1,153 positive reactors to the test, which I calculate to be a mere 0.31 per cent of cattle positive to the test (but not necessarily infected).

To my knowledge the third point, namely that all spread of bTB is due to super excreter infected cattle, is totally lacking evidential support.

I accept that we need to identify and remove infection in both species, but I will leave readers to come to their own conclusion as to which of the two species is likely to be currently more relevant as a reservoir of infection.

Roger Blowey

Gloucester