Mali has jailed 11 men for refusing to let their children be vaccinated against polio, a judge in the West African country said on Wednesday.

The paralysing disease has reappeared in 13 African countries in the last two years, setting back attempts to eradicate it.

Nearby Nigeria is believed to be the source of polio’s resurgence in Africa.

A northern Nigerian state banned vaccines in mid-2003 because Muslim elders said they were part of a Western plot to spread HIV and infertility, although immunisations resumed there after 10 months.

Sidiki Sanogo, the Malian judge passing sentence, said the 11 men, sentenced to between 6 months and 3 years in prison, were members of a Muslim sect whose leader only recognised the authority of God.

They were charged with “resistance, disobedience and rebellion against public authorities” after refusing to allow vaccination during a public health campaign in early March, because they believed it would make their daughters sterile, Sanogo said.

“They are an unknown sect whose members live shut away in a sort of monastery in the village of Boura, 20 km from Yorosso,” said Sanogo, a judge in Yorosso, 350 km (220 miles) east of Mali’s capital Bamako.

Polio, which mainly affects children under the age of five, is a viral disease that can cause irreversible total paralysis in a matter of hours. The vaccine works by infecting people with a benign virus, thus providing immunity to the harmful strain.

Health ministers from around Africa have vowed to halt the spread of the disease this year, with at least five rounds of national campaigns to vaccinate young children due to be held in the continent’s eight hardest-hit countries.