Less than four months ago the world was cheered to learn that India had gone a full year with no new cases of polio — a landmark that left only Pakistan, Afghanistan and Nigeria on the World Health Organization's list of countries where the disease is endemic.

But the battle is far from over, judging by the WHO's latest expressions of alarm. It says that in both Nigeria and Afghanistan the number is creeping up, while budget shortfalls are jeopardizing the effort to hold polio at bay in 24 other high-risk countries.

Right now the numbers of new infections are small. But Nigeria's total has jumped to 38 in the first five months of 2012 from just 10 in the same period of last year. Afghanistan's went from three to seven. Only Pakistan's number fell back, from 43 to 18.

The polio virus, which usually infects children in unsanitary conditions, attacks the nerves and can kill or paralyze. It can spread widely and unnoticed before it starts crippling children. On average about one in 200 cases will result in paralysis.