DHAKA:  Vital supplies and resources to tackle Ebola are beginning to arrive in the three worst-hit West African countries, Ghana's President John Mahama has said.

Mahama, who heads the regional bloc Ecowas, also told the BBC that treatment centres were being set up in Guinea, Liberia and Sierra Leone.

But he called for proper co-ordination between agencies to avoid duplication.

The outbreak has killed more than 4,500 people, almost all of them in those three countries, reports BBC.

An estimated 70% of those infected have died.

Meanwhile, Nigeria was declared free of Ebola after six weeks with no new cases, the World Health Organization said on Monday.

Last week, Senegal was declared virus-free.

In other developments:

The United Nations said one of its workers in Sierra Leone had died from the disease, becoming the third UN victim

US health officials said 43 people closely monitored after coming into contact with Ebola victim Thomas Eric Duncan had been given the all-clear after 21 days

Stricter guidelines have been issued for protecting US healthcare workers

The Spanish government said a nurse who became the first person to contract Ebola outside West Africa had now tested negative for the virus

Liberian President Ellen Johnson Sirleaf's son, physician James Adama Sirleaf, has decided to stay in the US, saying he could do more for his country there than at home, the World Street Journal reports.

BDST: 0944 HRS, OCT 21, 2014