Let me begin by paraphrasing a daughter's letter to her father, of June 1326:

I haven't wanted to upset you, but I am suffering from an illness of the head that will totally deprive me of sight, though I may be able to tell light from dark. Can you please find someone there who can help me better than the doctors here? They are calling this illness “cataract”, and apparently it can be cured if mine is the right kind, though no one here says it is.

The frightened daughter is the 25-year-old Princess Isabel, wife of Frederick of Austria, writing from Graz to her father James II of Aragon. Her anxious father wrote back immediately, asking her what her doctors said her symptoms were and what they thought had caused the illness, so that he could summon his own medical experts to see if they knew how she could be treated. Unfortunately, as it happened, James himself died the next year, before he could do anything further.

On 30 August 1998, the Mail on Sunday, under the headline “TB refugee ‘must be held in hospital’”, described the case of a Somalian man who had been “ordered by a court to remain in hospital for six months to prevent him spreading a highly infectious deadly disease”. That disease was tuberculosis and a court order had been issued “after the man had twice staggered into Northwick Park Hospital in Harrow, North-West London, for treatment but left without trace. He failed to take prescribed treatment and his condition rapidly deteriorated, forcing him to return to hospital a third time.”