BioEd Online

Polio has re-emerged in Guinea and Mali, countries that had previously freed themselves of the disease. The finding raises fears that a major polio epidemic could hit west and central Africa.

It is thought that the virus spread from Nigeria, one of the last strongholds of the disease. The new cases mean there are now 12 formerly polio-free countries that have been re-infected with virus since January 2003.

Guinea and Mali are home to one and two new cases respectively. Three new cases of polio paralysis have also been confirmed in Sudan's conflict-stricken Darfur region.

"It is a serious problem," says Bruce Aylward, coordinator of the World Health Organization's Global Polio Eradication Initiative. It highlights the need to boost population immunity levels across west and central Africa.

Breached defences

Guinea and Mali are outside a ring of African countries that performed coordinated immunization campaigns in February and March 2004 to try to halt the spread of polio from Nigeria and Niger.

Further synchronized vaccinations are planned in 22 countries, including Nigeria and Niger, in October and November 2004. Health professionals aim to immunize 74 million children under the age of 5.

But the Global Polio Eradication Initiative has warned that plans could be hampered by a cash shortfall of US$100 million.

Although similar campaigns in 2000 and 2001 stopped polio transmission in most of these countries, civil unrest in Côte d'Ivoire and Darfur will make it hard to reach every child this year. "It's a major challenge that has to be planned for," says Aylward. But he is optimistic that years of experience gained in troubled regions such as Sudan and the Congo will help health workers to achieve their goal.

Polio is still routinely found in six countries: Nigeria, India, Pakistan, Niger, Afghanistan and Egypt. But the virus has been known to spread from these hotspots to at least ten other countries, including Sudan.

Concern has been mounting throughout the year over the situation in Nigeria's Kano state where unfounded rumours linking the polio vaccine with HIV put immunization plans on hold. Vaccinations resumed just a short time ago, on 31 July. "The new outbreaks are likely to shake people out of any complacency they have been feeling since the Kano vaccinations resumed," says Aylward.