The World Health Organization reported four new cases of Ebola in Nigeria on Friday, all of them among health-care workers and others who had contact with American consultant Patrick Sawyer, a spokesman said.
“They’re all contacts of Patrick Sawyer,” said Gregory Hartl, a spokesman for the WHO in Geneva. He said all are health-care workers, cleaners or others at the hospital where Sawyer was taken after he collapsed in the airport following a flight from Liberia to Nigeria. “We know that he had contact with very few people at the airport,” Hartl said. Another pic after cut

:Liberian nurses bury the body of an Ebola victim Wednesday near Monrovia. According to the WHO on Friday, there are 1,779 cases of Ebola in Guinea, Liberia, Sierra Leone and Nigeria, including 961 deaths. (Ahmed Jallanzo / European Pressphoto Agency)
Sawyer died July 25 and a nurse involved in treating him died about 10 days later, according to Nigeria’s health ministry.
According to the WHO, there are 1,779 cases of Ebola in Guinea, Liberia, Sierra Leone and Nigeria, including 961 deaths.
The WHO declared the Ebola outbreak in West Africa an international public health emergency Friday, recommending strict monitoring of travelers in the four stricken countries. It said emergency efforts should be put under the direct command of heads of state.
In nations that do not border the affected area, the WHO recommended no general travel ban but said governments should be prepared to “detect, investigate, and manage Ebola cases,” including “the capacity to manage travelers originating from known 
Ebola-infected areas who arrive at international airports or major land crossing points with unexplained febrile illness.” It also urged countries to be prepared to evacuate their citizens, mainly health-care workers, who have been exposed to the virus.
The new Ni­ger­ian cases bring the total number of probable or suspected cases there to 13, according to WHO statistics released Friday. Any spread beyond the transmission chain started by Sawyer in Lagos, a city of 21 million, or Nigeria, a country of 177 million, would be cause for great concern, but officials are hopeful that has not occurred. Contacts of the people who have fallen ill are being traced, Hartl said, but Ebola is not contagious until its victims begin to show symptoms, such as high fever.
The Nigerian ambassador to the United States, Adebowale Ibidapo Adefuye, said there have been no Ebola cases outside Lagos. He said committees of doctors and experts have been set up by the government to respond, and those suspected of having the virus will be quarantined.
“It’s natural to be worried, but we’re confident that the measures being taken by the government will contain it,” Adefuye said Friday, urging Nigerians not to be panicked by rumors.
Goodluck Jonathan, Nigeria’s president, declared Friday that containment of the Ebola virus is a national emergency. He approved the release of $11.7 million to establish more isolation centers, beef up screening at borders and deploy more personnel.
The president asked the public not to spread false information that could lead to “mass hysteria, panic and misdirection,” including unsubstantiated suggestions about the “prevention, treatment, cure and spread of the virus,” a spokesman said.
In other developments, Canadian drugmaker Tekmira Pharmaceuticals said Thursday that the U.S. Food and Drug Administration had removed a “clinical hold” it had placed on the company’s experimental Ebola drug, potentially clearing the way for its use in patients battling the lethal virus.
The company has a $140 million contract with the U.S. government to develop its TKM-
Ebola drug, which had shown promising results in treating non-human primates. The drug had been progressing through the FDA approval process until last month, when the agency halted a trial of the drug to seek more information about its safety.
Another experimental drug, ZMapp, manufactured by a San Diego company, was given to U.S. missionaries Kent Brantly and Nancy Writebol, who contracted the virus while aiding victims in Liberia. It is too early to determine whether the cocktail of antibodies, never tested on humans, might have helped the pair survive. Both have been brought back to Emory University Hospital in Atlanta, where they continue to improve slowly, according to reports.