The UN health body said on Friday its emergency committee, which includes global medical and policy experts, had declared the deadliest known outbreak of the Ebola virus a "public health emergency of international concern".

World Health Organization Chief Margaret Chan said the crippling Ebola epidemic was the worst of its kind in four decades.

Chan urged the international community to step in and assist countries struggling to deal with the deadly hemorrhagic fever whose spread she declared a global health emergency.

The virus spreads through direct contact with infected blood, feces or sweat. It can also be spread through sexual contact or the unprotected handling of contaminated corpses. Ebola was first discovered in the Democratic Republic of the Congo in 1976 in an outbreak that killed 280 people.

BA/BA