Nairobi, 9 November 2010 (IRIN) - At least 94 people have died, with 201 cases of acute flaccid paralysis reported in the Republic of Congo (ROC), since 5 November. Four cases have been confirmed as wild poliovirus type 1, says the UN World Health Organization (WHO).

"This is because [for the last] 15 years, immunization campaigns have not been carried out due to the country's political instability. People who were not vaccinated are vulnerable to the polio virus," Rod Curtis, a communications officer with WHO's Global Polio Eradication Initiative, told IRIN.

Most affected are people aged between 15 and 72.

Improving water and sanitation practices can help but in an emergency situation like this, one of the fastest and most effective ways of stopping the outbreak is through cross-border mass immunization because of population movements, said Curtis.

Polio is an acute viral disease mainly affecting children under five that may attack the central nervous system and is characterized by symptoms ranging from a mild non-paralytic infection to total paralysis in hours.

At least 1.1 million people will be vaccinated in the epidemic's epicentre in ROC's Pointe-Noire region. Another 600,000 people will be simultaneously vaccinated in neighbouring Kebinga Province of Angola starting 11 November, said Curtis.

Congo recorded its last case of indigenous polio in 2000 and WHO suspects the virus reached Pointe-Noire through Kebinga, where 25 cases were recorded in 2010, Curtis told IRIN.

A recent polio immunization campaign targeted some 72 million children in 15 countries across West and Central Africa, the third in 2010.

"If all African countries continue to immunize children and maintain surveillance systems, we'll witness a serious decline in the virus," said Curtis.

Nigeria, the only remaining polio-endemic country in Africa, has reduced the number of recorded polio cases from 382 in 2009 to 10 in 2010 with regular immunization. Angola recorded 25 cases and the DRC 30 in 2009. These three countries represent the greatest threat to polio eradication in Africa, says WHO.