An international team of doctors is set to launch a desperate, last-ditch bid to save Africa from polio, a scourge once believed to have been defeated but which has recently returned to haunt the continent.
Scientists say the attempt is a make-or-break effort to eradicate this crippling, sometimes fatal illness. Success would see poliomyelitis follow smallpox and become the second disease to be completely eradicated from the planet. Failure, and the disease could slip though the net of international controls set up to contain it, and undo 17 years of international effort costing ?1.6 billion.
"It is now or never," said Sona Bari, of the Global Polio Eradication Initiative. "We are going to have to be very determined, however. The disease has come back because we slackened our effort and became complacent. We cannot let that happen again."
Until last year, an international campaign to rid the planet of polio had proceeded almost flawlessly. Numbers of cases had dropped from more than 300,000 a year to fewer than a thousand. A disease that in the 1990s was found in 125 nations was confined to a few pockets of Asia, and to Africa where most cases are concentrated into parts of Nigeria, Niger and Egypt.
But in 2003, anti-Western hostility erupted among Muslims in northern Nigeria's Kano region. They claimed vaccines were tainted with HIV and poisons to make women infertile and refused to cooperate with doctors.
"All kinds of rumors were going around," said Jonathan Majiyagbe, a Kano resident and a past president of Rotary International which has played a key role in funding the polio eradication program. "Some clerics made all sorts of wild accusations."
The consequences were devastating. The eradication program was brought to a sudden halt and, within months, the disease reappeared in countries that had struggled for years to eliminate it with hard-fought success. They included the Ivory Coast, Burkina Faso, Chad and Sudan. In Nigeria -- which had reduced its cases to a few dozen -- there was an outbreak of more than 800 cases.
This last figure represents the tip of an iceberg, however. Polio -- which is spread by person to person contact and invades a victim's nervous system -- only causes detectable paralysis in about one in 200 victims. This means that at least 160,000 people must have been infected. Unaware of their condition, they will then have gone on to infect others.
"Countries that thought they had eradicated the disease let their guard down," said Bruce Aylward, co-ordinator of the polio initiative. "Vaccination levels had dropped, and the disease began appearing all over the place."
Most worrying was the appearance of the disease in children in Sudan, with outbreaks spreading from Darfur to Khartoum and then to Port Sudan. Eventually one case, in a young Sudanese child, was reported from Saudi Arabia.
An affliction that seemed destined to have been wiped from the face of the planet began to spread remorselessly across Africa, sounding alarm bells among international agencies including the World Health Organization (WHO) and Unicef. Last October, polio campaigners regrouped and launched an attempted mop-up campaign to halt the disease's new spread. Doctors are optimistic about its prospects, but most estimates suggest that it will cost at least an extra ?50 million to get back on the road to final elimination.