Source: AP/Press Association ImagesAN AMERICAN DOCTOR who contracted the deadly ebola virus while working in Africa has seen a “slight improvement” in his condition.Kent Brantly, a doctor working for charity Samaritan’s Purse, and Nancy Writebol, a missionary with SIM, have both shown improvement in the past 24 hours, Samaritan’s Purse said. However, both remain in serious condition in Liberia where they are being treated for the virus.Because of instability and ongoing security issues in the area, Samaritan’s Purse says it is curtailing operations in Liberia. Non-essential personnel are being evacuated but medical staff are remaining on site to treat patients.“We are doing everything possible to help Dr. Brantly and Nancy,” Samaritan’s Purse President Franklin Graham said. “We ask everyone to please pray urgently for them and their families.”Dr. Brantly, a family practice physician, was serving in Liberia through the post-residency program before joining the medical team responding to the ebola crisis. His wife and two children had been living with him in Liberia but flew home to the US about a week ago, before he started showing any signs of illness. Source: PA GraphicsSierra LeoneSierra Leone leader Ernest Bai Koroma declared a state of emergency today, cancelling a planned trip to the US-Africa summit as the country struggled to contain the deadly epidemic.“Extraordinary challenges require extraordinary measures. The Ebola virus disease poses an extraordinary challenge to our nation,” the president said in a televised address to the nation.“Consequently… I hereby proclaim a state of public emergency to enable us to take a more robust approach to deal with the Ebola outbreak.”Koroma said he had cancelled a trip to a summit of around 50 African leaders in Washington DC next week.He cancelled foreign trips by ministers and other government officials, exempting only “absolutely essential engagements”.The president said the measures would be in place initially for 60 to 90 days, and would then be reassessed.He declared Monday August 4 “National Stay at Home Day”.Elsewhere, Liberia announced it was shutting all schools and placing “non-essential” government workers on 30 days’ leave. Source: PAAction needed A medical worker from the U.S. Centres for Disease Control and Prevention, researchers who are working on the Ebola outbreak in Uganda, works at their laboratory in Entebbe 42kms (29 miles) from the capital Kampala Source: AP/Press Association ImagesIrish charity Plan Ireland, who are working on the ground, say that global action is needed to prevent a pandemic.Speaking from Sierra Leone, Plan Ireland’s Suzanne Walker said;“With no effective treatment, raising awareness of the risk factors of ebola infection and the protective measures individuals can take is one of the few ways to reduce human infection and death.“Plan is responding by complementing local governments’ efforts, particularly in the area of public health information and providing material support to contain the spread of the disease. We have printed and distributed thousands of health promotion brochures across infected areas. We are disseminating prevention messages via TV, radio and SMS.“Plan is supplying equipment, fuel, disinfectants and training local health workers to try and stop more people from becoming infected. We are also training volunteers to disinfect public and household latrines, treating the homes of suspected cases, and setting up hand washing systems in schools and public areas.”In the UK, two men tested for the virus were found not to be suffering, but a union chief for border control workers said that staff were not ready to deal with people with ebola coming through.Read: Canadian doctor quarantined as ebola outbreak continues to spreadVideo: What exactly is the Ebola virus?