Commerce was already associated with infection during the Black Death, though it would be hundreds of years before rats were singled out as its carrier, and the first quarantines followed soon after.

ECONOMIST: Where and when will the next pandemic emerge?

The Black Watch first fought in Iraq in April 2003 as part of the 7th Armoured Brigade, which led the Desert Rats' attack on Basra, the country's second city.

BBC: NEWS | UK | Scotland | Black Watch heads back to Iraq