(CNN) -

The World Health Organization says the current Ebola "epidemic trend shows a mixed picture," in Africa according to a statement released early Tuesday.

Liberia reported 16 new cases with nine deaths. Sierra Leone has 34 new cases and 14 deaths and that's just since last week. The WHO statement suggests the growing number of cases in these countries means that there is still a problem with active viral transmission.

There has been some progress in Guinea. WHO says there has been a reduction in the number of new cases reported in Guinea. In fact, it has been a week since a new cases has been reported in that country. There have, however, been two deaths reported.

With their countries facing an Ebola epidemic of "unprecedented" proportions, the health ministers of 11 African nations have agreed to a joint strategy to try to stem its deadly advance.

As part of the plan, the World Health Organization will set up a "sub-regional control center" in Guinea -- one of the three West African nations at the heart of the outbreak -- to help coordinate the response.

The strategy was announced late Thursday at the end of a two-day summit in Ghana that brought together ministers from the Democratic Republic of the Congo, Gambia, Ghana, Guinea, Guinea-Bissau, Ivory Coast, Liberia, Mali, Senegal, Sierra Leone and Uganda with health experts, Ebola survivors and WHO representatives.

It also calls for better surveillance and reporting of cases, the mobilization of community and political leaders to improve awareness and understanding, and greater cross-border communication.

WHO has previously warned that "drastic action" is needed to halt the spread of the virus, which can kill up to 90 percent of those infected.

Addressing the closing session, Dr. Luis Gomes Sambo, WHO regional director for Africa, welcomed the move.

"It's time for concrete action to put an end to the suffering and deaths caused by Ebola virus disease and prevent its further spread," he said.

WHO reports there have been 844 cases, including 518 deaths, in Guinea, Sierra Leone and Liberia as of Sunday.

'Enormous' impact

The impact of the outbreak, which began in March, "has been enormous in terms of loss of human lives and negative socioeconomic effects," Sambo said.

The disease's spread "is in great extent associated with some cultural practices and traditional beliefs" that run counter to preventive health measures, he said.

According to a WHO statement, such traditional practices foster "mistrust, apprehension and resistance" in local populations regarding health workers' efforts.

These include the hiding and treatment at home of Ebola victims and funerals at which mourners touch the body of the deceased. "These are very high-risk practices leading to extensive exposures to Ebola virus in the community," the statement said.

Sambo added, "The extensive movement of people within and across borders has facilitated rapid spread of the infection across and within the three countries."

He also paid tribute to those on the front lines of the fight against the deadly disease, saying health workers have been "disproportionately affected," with more than 60 cases and 32 deaths reported among their ranks.

Uganda takes steps

Uganda's health authorities, who took part in the summit in Ghana, announced new measures Friday to screen people arriving from Ebola-affected countries.

"All border posts have been told to intensify disease surveillance check points," Ugandan Health Minister Ruhakana Rugunda said.

"Special focus is on anyone with travel history of the past three months from the three West African countries of Guinea, Sierra Leone and Liberia."

Although no travel ban is in place, Ugandan residents have also been urged to limit nonessential travel to those three countries.

Rugunda said Uganda, which has experience in dealing with Ebola outbreaks, most recently in 2012, had been asked by WHO to provide technical assistance in the latest battle to contain the virus.

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