Alzheimer's may remain incurable for now, but not for want of effort. In May President Barack Obama proposed an increase of $100m in the budget to fight it, after advisers set a deadline of 2025 for developing a cure. In France last July Nicolas Sarkozy, then President, committed to tackling it. And in March, David Cameron announced a doubling of research funds.

For researchers like Dr Martin Rossor, who with his colleagues at the National Hospital in London has been eking out modest research grants for more than 20 years, the blaze of attention is welcome. "The whole thing's gone up a gear," he said. And the reasons are plain: as Mr Cameron pointed out, at £19bn, Alzheimer's costs the taxpayer more than cancer, heart disease or stroke, and within 10 years, given the increase in longevity, one million of us will be diagnosed with it.

Dementias are the latest in a long line of diseases to attract attention from governments and summon a well-funded response. In 1933 the World Health Organisation declared tuberculosis "a global health emergency." In 1971 Nixon declared war on cancer. In the 1980s and '90s it was HIV/Aids that prompted a huge injection of research funding. In between there have been wars on polio, smallpox and measles. The burden on hospitals and the lure for drug companies of new income streams combines to bring fatal diseases into the spotlight.

But diseases can just as easily fall out of fashion. In the US alarm bells have rung as support for the campaign against Aids has waned; the war on cancer has not been won. There is the odd unequivocal triumph – the last case of smallpox was diagnosed in 1977 – but diseases like malaria and TB which should have been whipped decades ago continue to claim millions of victims, far from our eyes.