In a statement, The United Nations agency urged community and religious leaders to ensure that herders and farmers who are at greatest risk know measures to take so as to avoid infection.

The deadly virus can be transmitted to humans by handling of animal tissue during slaughtering or butchering, helping with animal births and in veterinary procedures. Human infections can also result from mosquito bites and consuming unpasteurised or uncooked milk or meat of infected animals, according to the WHO.

People who come into contact with cattle, sheep and other animals need to adopt "safe handling and slaughtering practices", the WHO said.

Sudanese health authorities sought help to combat the human outbreak in mid-October, the WHO has said. But Sudan's Ministry of Animal Resources has said more recently there is no sign of the disease in the country's huge livestock industry.

More than 221 new human cases have been reported in the last two weeks in White Nile, Sennar and Jazeera provinces in central and eastern Sudan, the WHO said on Thursday.

The overall figures include cases reported in Khartoum state, which it said were most likely infected in the three other areas.

Intensive social mobilisation efforts were urgently needed through media, "community and religious leaders to ensure that at-risk communities are fully aware of the measures that need to be taken to reduce the risk of human infection", the WHO said.