On foot and by bicycle, an army of 28,000 people advanced through towns and remote villages in Ivory Coast Sunday to vaccinate children against polio in an effort to finally defeat the crippling disease.

Ivory Coast was polio free in 2001 but the outbreak of civil war a year later wreaked havoc with immunization campaigns and 17 cases were recorded last year in the West African country, still divided by a buffer zone manned by U.N. peacekeepers.

This weekend’s mission in Ivory Coast and neighboring Liberia is part of a continent-wide campaign to vaccinate more than 100 million children in 22 west and central African nations against polio in the space of a few days.

The World Health Organization said Friday the disease was spreading across Africa and 13 out of 14 previously polio-free countries to record cases are in the world’s poorest continent.

In the remote village of Guin-Houye in Ivory Coast’s rebel zone, not far from the porous frontier with Liberia, vaccinators marched from one mud hut to the next under the burning sun, carrying cool boxes loaded with polio vaccines.

“Some of my children have already had (the vaccine), so I knew what it was,” said Rosalie Deye, 32, surrounded by some of her 10 offspring. “I tried to encourage other women to have their children vaccinated.”

Organizers said there was no guarantee every child would be immunized but they were trying to ensure none would slip through the cracks during up to five rounds of vaccinations slated for each of the countries this year.

“It didn’t taste bad, I wasn’t scared,” said Kevin, 4, as he waited with a crowd of shoeless infants to have his finger dipped in purple ink to show he had taken the two-drop vaccine.

“POLIO, NO, NO, NO”

Some 25 km (16 miles) further west in Liberia, past teenage rebel fighters standing guard at the frontier with assault rifles and solemn expressions, teams of health workers were tracking down children in the border town of Loguatuo.

“Polio, no, no, no,” bellowed one man through a megaphone as bystanders gathered to watch the spectacle of a young man crippled by polio limping around in a circle and being chased by another sufferer waving a stick.

Polio is a virus contracted from fecal oral contact, which usually leaves victims unable to walk.

The campaign here, spearheaded by the United Nations Children’s Fund (Unicef), Rotary International, local charities and governments, aims to vaccinate 5 million children in Ivory Coast and nearly 1 million in Liberia.

“If we can vaccinate at least 90 percent of these children, we will finish up by eradicating polio,” said Dr Abdelhak Bendib, Ivory Coast’s Unicef health officer in the western cocoa town of Daloa, which is under government control

“We can’t talk about eradication in one country because the virus crosses borders,” he said.

WHO officials say it originated in Nigeria 18 months ago, after the northern state of Kano suspended vaccinations, and has traveled east as far as Sudan and Saudi Arabia.

Ivory Coast’s President Laurent Gbagbo kicked off the campaign in Daloa Friday giving the vaccine to some infants in their mothers’ arms.

“I’m not a doctor or nurse, but if (Didier) Drogba had polio would he be playing football today?” said Gbagbo, referring to Ivory Coast’s soccer star who plays for British league leaders Chelsea.