Freetown , Sierra Leone ( CNN ) -- Guinea has closed its border with Sierra Leone to suppress the spread of the deadly Ebola virus , a Sierra Leone border police official told CNN . The virulent virus continues to advance from its epicenter in Sierra Leone to neighboring Guinea , Liberia and Nigeria . Other West African governments are attempting to contain the outbreak , which has been declared a `` public health emergency of international concern '' by the World Health Organization . The United States and the United Kingdom welcomed the efforts of the World Health Organization to halt the spread of Ebola and on Saturday vowed to increase assistance to help combat the disease in West Africa . Treating Ebola in Sierra Leone : 'We are two steps behind ' Meanwhile , the Zambian government banned arrivals of people from countries where there has been an Ebola outbreak , as a preventative measure to stop the virus from entering the country . `` All delegates from any of the countries affected by Ebola Virus disease are restricted from entering Zambia until further notice , '' said Dr. Joseph Kasonde , Zambia 's Minister of Health in a statement on Saturday . Ebola virus : 9 things to know about the killer disease . Since the onset earlier this year , the virus is believed to have infected 1,779 people , killing 961 according to the latest figures released by WHO . Nigeria and Liberia have both declared a state of national emergency this week , in an effort to control the unprecedented epidemic . Canadian health officials announced Saturday that a patient who recently traveled to Nigeria is being tested for Ebola . The patient is being treated in isolation at Brampton Hospital in the Toronto area after complaining of fever , headache and malaise . Those test results are expected by the end of the weekend , according to hospital spokesman David Jensen . The U.N. health agency described the global Ebola situation as the worst outbreak in the four-decade history of tracking the disease . WHO : Ebola outbreak in West Africa an international health emergency . Initial Ebola response called a 'failure ' Opinion : Make more Ebola drug and give it to Africans . CNN 's Nana Karikari-apau contributed to this report .
U.S. and UK commit to increase aid to West Africa . Zambia bans travelers from Ebola countries . Guinea , Liberia and Sierra Leone and Nigeria are battling Ebola .