South Sudan has scaled up Ebola screening at its border with the Democratic Republic of Congo after a case of the deadly virus was confirmed just 70km (43 miles) from the border, a health ministry official told South Sudanese radio station Radio Miraya.
Dr Richard Lino Laku said a team had been sent from the capital, Juba, to Yei River state to support local health officials.
He also said that they are on the look-out for people who could have used "illegal routes" to get into the country from DR Congo, where more than 2,300 cases of Ebola have been recorded in the last 11 months.
The person with Ebola 70km from South Sudan is a 40-year-old woman who travelled 500km from Beni, in DR Congo's North Kivu province, according to Voice of America quoting Congolese officials.
The latest outbreak of Ebola has killed more than 1,500 people in DR Congo, the World Health Organization says.
The WHO says "national and regional risk levels remain very high" but the current outbreak has not been declared a global threat.
Last month in Uganda, two people who had travelled from DR Congo died of Ebola, but there have been no other cases recorded outside DR Congo since then.