Porous borders and insecurity have heightened fears that the Ebola outbreak that has claimed more than 1,400 lives in DR Congo could easily spread to South Sudan and the wider eastern Africa.
The virus has already claimed two lives in Uganda of a family whose members visited DR Congo for a burial but Uganda President Yoweri Museveni says the situation has been contained.
A suspected case is also under observation in Kenya and Somalia, and conscious of the potential risk, has put its health facilities on notice while assuring its citizens that all is well.
The Ebola alert in eastern Africa follows a finding by the World Health Organisation (WHO) last week that the outbreak in DRC, while not warranting declaration of an international health emergency, was grave enough to pose risks in neighbouring countries.
Residents at the common borders of Uganda and Congo said there were several feeder routes without Ebola screening points, health facilities and health workers.
"We are moving freely from DRC to South Sudan and nobody asked us about where we are coming from upon reaching Yei town. It's only in Yei town I saw Ebola centers and concerns about the disease," John Taban a resident of Senema area of Otogo County in South Sudan told the Nation.
Mr Taban said governments and humanitarian agencies need to create awareness "deep in the villages."
"Seriously if nothing is done, with the cold weather, rains and free movement of civilians from DRC, Ebola is most likely to start in Yei River State and spread to the rest of South Sudan," he warned.
Margret Elisa, a resident of Yei's Morobo County which connects to Uganda and Congo expressed similar fears.
Humanitarian agencies operating in Yei State, however, said insecurity made it difficult to reach the villages with armed groups, governments or rebel forces restricting access.
"We have the capacity to establish Ebola screening centers and install health officials away in rural areas. Our fear is that once we are there we become victims of the situation," one humanitarian worker said.
Such fears are real in DR Congo where health workers in Butembo, one of the districts worst hit by Ebola have been attacked by armed groups looking to snatch their provisions, medicines and other valuables.
WHO had threatened to move health workers from war zone (Eastern North Cape and Ituri provinces after a series of attacks on health centers and abductions of health workers led to several fatalities.
President Museveni said after meeting with WHO director general Tedros Adhanom Ghebreyesus in Entebbe on Monday that the situation had been contained.
"The public should stay vigilant and observe guidelines issued by health officials. We agreed on stepping up our primary health sensitisation drives across the country," President Museveni said on Twitter.
Dr Tedros said a vaccine that was being administered to those who had come in contact with the victims had helped contain the situation with its 97.8 per cent success rate.
South Sudan minister of health Kogo Manase said social mobilisers were moving from house to house conducting awareness.
"We are also using local radio stations to inform people about preventive measures on the disease. We have set up an Ebola treatment Isolation Center and also have a mobile Ambulance to respond to any suspected Ebola case," Mr Manase said.
So far Ebola screening centers have been established in Lasu (South Sudan-Congo border) and Kaya (South Sudan-Uganda border), leaving about 15 entry points without screening facilities.
"Our biggest fear has been the issue of insecurity and free movement across the border without using official entry points. With this we are at high risk," he said.
He appealed to people to use official routes and to armed personnel to give passage to humanitarian workers.
South Sudan made an emergency appeal for $12 million last Thursday to bolster its Ebola preparedness.
Somalia Federal minister for health Fawzia Abikar Nur said on Sunday that the government was closely monitoring the situation in neighbouring countries and was working with WHO to prepare for any eventualities.
"We have alerted all health institutions in the country about the dangers of Ebola," Dr Nur said.
In Kenya, screening was stepped up at major entry points as the results of tests conducted on the suspected case in western Kenya were keenly awaited.
Public and private health facilities in Bomet County, which neighbours Kericho county where the Kenya case is suspected, have put in place precautionary measures to combat Ebola.
Kenya has also deployed health workers who were in 2015 sent to Sierra Leone and Liberia to combat the disease as part of an African Union mission to enhance surveillance at border points.
Tanzania, Rwanda and Burundi have also increased their surveillance following the deaths in Uganda.
The WHO reported that as of June 11 there were 2,084 Ebola cases including 1,990 confirmed and 94 probable cases and 1,311 deaths in the DR Congo.
Ebola is a deadly viral disease that causes high fever, body aches, diarrhoea and bleeding often killing victims within days.
Additional reporting by Abdulkadir Khalif.