Ethiopia has launched an emergency polio immunization campaign, fearing an outbreak of the disease in neighboring Sudan could spread, the Health Ministry said on Friday.

Ethiopia has not recorded a polio case in four years and expects to be certified as polio-free by the World Health Organization (WHO) by the end of the year. It said it would immediately begin vaccinations in six states bordering Sudan.

The 19 people found to have polio in Sudan were about 70 km (44 miles) from the Ethiopian border, the ministry said.

“Unless the threat from Sudan is not reversed, the gains achieved so far will dissipate into thin air,” the ministry said in a statement, adding that the campaign would target 300,000 children under the age of five.

Polio is now endemic to only six countries, but since 2003 twelve African countries have reported infections imported from Nigeria, where the virus still exists, according to the Global Polio Eradication Initiative, an organization backed by WHO and others that coordinates immunization campaigns.

Sudan was among the countries where the disease was found to have been imported. The Global Polio Eradication Initiative plans synchronized vaccinations throughout 23 African countries before the end of the year and in 2005.