By Jennifer Rigby LONDON (Reuters) – A smattering of monkeypox cases in Britain has prompted authorities to offer a smallpox vaccine to some healthcare workers and others who may have been exposed, as a handful more cases were confirmed in parts of Europe. Monkeypox is a usually mild viral illness, characterised by symptoms of fever as well as a distinctive bumpy rash. There are two main strains: the Congo strain, which is more severe – with up to 10% mortality – and the West African strain, which has a fatality rate of about 1%. First identified in monkeys, the viral disease typically spreads…