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 The deadly Ebola virus that’s killed more than 600 people so far in West Africa may have been smoldering there for years and has almost certainly sickened people who thought they had something else, researchers say. 
 
 A new study of blood samples from people being treated for a serious, viral-like illness in years past in Guinea, Sierra Leone and Liberia suggests some of them could have been infected with Ebola. Now researchers are digging deeper to see if the virus has always been lurking there, just undetected. 
 
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 It’s not a perfect test — the blood samples were several years old and had to be heat-treated so the researchers would be safe — but it’s a lead worth following up, said Randal Schoepp of the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID) team that did the research. 
 
 “It had been circulating there for a long time,” Schoepp told NBC News. “It just hadn’t gotten out of control or the right conditions weren’t there.” 
 
 “It had been circulating there for a long time." 
 
 Other researchers said the tests used are not 100 percent reliable, and more testing will be needed to see if they reflect what’s really happening. But it would be unlikely for a virus such as Ebola to appear completely out of the blue in a region. Experts suspect bats and perhaps other animals, too, carry the virus. 
 
 “It makes us realize that you don’t have to see an outbreak (to know a virus is circulating in an area),” Schoepp said. “In Africa, it is easy for a disease to smolder because there is so much disease.” 
 
 Ebola has killed at least 613 people in Guinea, Sierra Leone and West Africa in an outbreak that started in spring, according to the World Health Organization. It’s been diagnosed in 982, making for a mortality rate of more than 60 percent. 
 
 The WHO and Medecins Sans Frontieres (Doctors Without Borders) both say the outbreak is out of control. It killed 25 out of 28 nurses in a single hospital in Sierra Leone and patients are disappearing into the forest rather than seek treatment. 
 
 Ebola had never been seen in West Africa before, although there are plenty of other nasty infections, from malaria to dengue and, especially, Lassa fever. Lassa fever is caused by a virus unrelated to the one that causes Ebola but causes similar symptoms, include high fever, vomiting and internal and external bleeding. 
 
 Lassa is a far bigger problem than Ebola — it infects between 100,000 and 300,000 people a year in West Africa, killing 5,000, according to the U.S. Centers for Disease Control and Prevention. 
 
 So when someone shows up with a fever in West Africa, Lassa is a prime suspect. 
 
 Several U.S.-based organizations have been studying Lassa in Sierra Leone in the decade since a civil war there ended. But not everyone has Lassa or malaria — the majority of infections are never diagnosed. 
 
 “Generally only 30 percent to 40 percent of samples tested are positive for Lassa virus,” Schoepp’s team wrote in the journal Emerging Infectious Diseases. 
 
 Schoepp’s team looked at blood samples taken from 253 people cleared of both Lassa and malaria between 2006 and 2008. “Most samples were from acutely ill patients from eastern Sierra Leone; some were submitted from Liberia and a few from Guinea,” they wrote. ||||| MONROVIA/FREETOWN (Reuters) - People in Sierra Leone and Liberia filled churches on Sunday to seek deliverance from an outbreak of the deadly Ebola virus, defying official warnings to avoid public gatherings to contain an epidemic that has killed nearly 1,000 people in West Africa. 
 
 With their creaking healthcare systems completely overrun, Sierra Leone and Liberia have both declared states of emergency to tackle the highly contagious and incurable disease, which has also stricken neighbouring Guinea. 
 
 People still flocked to sing and pray at churches in Liberia's ramshackle ocean-front capital Monrovia, many of them comparing Ebola to the brutal civil war that ravaged the country between 1989 and 2003, killing nearly a quarter of a million people. 
 
 One of the deadliest diseases known to man, Ebola kills up to 90 percent of those infected. Discovered nearly 40 years ago deep in the forests of central Africa, its symptoms include internal and external bleeding, diarrhoea and vomiting. 
 
 "Everyone is so afraid," said Martee Jones Seator at Saint Peter's Lutheran Church. "Ebola is not going to shake our faith in any way ... because we've been through difficult times." 
 
 With the disease now in four African countries - following the death in Nigeria last month of a U.S. citizen who arrived from Liberia - the World Health Organisation (WHO) on Friday classified the epidemic as an international health emergency. 
 
 The WHO has said that the world's worst outbreak of Ebola -- with 1,779 cases and 962 deaths -- will likely continue for months as the region's healthcare systems struggle to cope. It has appealed urgently for funding and emergency medical staff. 
 
 A WHO medical ethics committee will discuss next week the use of experimental drugs to tackle the outbreak after two U.S. aid workers showed improvement after being treated with ZMapp, a drug developed by California-based Mapp Biopharmaceutical. 
 
 Spain on Sunday authorised the use of the ZMapp on 75-year-old Spanish priest Miguel Pajares - the first European infected - who was evacuated to Madrid last week after contracting the haemorrhagic fever while working in a hospital in Monrovia. A Congolese nun who worked with him died there on Saturday. 
 
 British drugmaker GlaxoSmithKline said on Sunday a clinical trial of a vaccine was due to start shortly. Three U.S. laboratories established to quickly make vaccines in the event of a public health threat also said they were standing by to support any U.S. effort to tackle Ebola. 
 
 With no other treatment available, churches in Monrovia furnished plastic buckets containing chlorinated water for worshippers to disinfect their hands. Inside, pastors told their congregations to follow instructions from health workers, some of whom have been attacked by locals terrified by the disease. 
 
 "We are in trouble here. We are in trouble," Reverend Marcus MacKay, dressed in a green gown, said before the altar. "But you know what? There is no way this devil is going to do its work!" 
 
 STARTED IN FORESTS OF GUINEA 
 
 Though this outbreak was first identified in March in the remote forest region of southeastern Guinea, scientists have traced the first recorded case as far back as early December, to a 2-year-old boy near the town of Gueckedou. 
 
 Many believe the virus was carried by fruit bats from central Africa, where it is regarded as endemic. Yet it is not clear how it jumped into the human population in West Africa. 
 
 Quarantine measures imposed on infected communities have hit trade and food supplies in some of the world's poorest countries. 
 
 In Sierra Leone, Bishop Abu Aiah Koroma of the evangelical Flaming Bible Church in Freetown said price hikes were destroying the nation's economy, branding Ebola "a devil". 
 
 Speaking amid chants of "Alleluia" and "Amen" from his packed church, Koroma called for penitence "to avert this plague from our country". 
 
 Concern over the spread of Ebola grew after it spread to Nigeria - Africa's most populous country - in late July. Seven cases of Ebola have now been confirmed there, including two deaths, and authorities have declared a national emergency. 
 
 In a bid to prevent Ebola reaching the United States, health officials in North Carolina said on Sunday they would require missionaries and others coming home after working with people infected with Ebola to be placed in quarantine. 
 
 Burkina Faso became the latest African country on Sunday to announce stringent airport health checks and border controls to protect itself from infection. 
 
 In Senegal, which borders Guinea to the north, a man has been isolated in the northern region of Matam while tests were conducted for Ebola, the APS state news agency reported. 
 
 Tests on suspected cases in Hong Kong, Canada and Saudi Arabia in recent days have all proved negative. 
 
 (Reporting by Daniel Flynn; Editing by Stephen Powell and Sandra Maler) ||||| CONAKRY Guinea has received confirmation that a mysterious disease that has killed up to 59 people in the West African country, and may have spread to neighboring Sierra Leone, is the hemorrhagic fever Ebola, the government said on Saturday. 
 
 Cases of the disease - among the most virulent pathogens known to infect humans, with a fatality rate of up to 90 percent - have been registered in three southeastern towns and in the capital Conakry since February 9. It has never before been recorded in Guinea. 
 
 "It is indeed Ebola fever. A laboratory in Lyon (France) confirmed the information," Damantang Albert Camara told Reuters. 
 
 Six of the 12 samples sent for analysis tested positive for Ebola, Dr. Sakoba Keita, who heads the epidemics prevention division at Guinea's health ministry, told Reuters. 
 
 He added that health officials had registered 80 suspected cases of the disease, including 59 deaths. 
 
 "But you have to understand that not all the cases are necessarily due to Ebola fever. Some will have other origins, including a form of severe dysentery," Keita said. 
 
 World Health Organization (WHO) officials said that cases showing similar symptoms, including fever, diarrhea, vomiting and bleeding, had also been reported in an area of Sierra Leone near the border with Guinea. 
 
 Sierra Leone's chief medical officer, Dr. Brima Kargbo, said authorities were investigating the case of a 14-year-old boy who died in the town of Buedu in the eastern Kailahun District. 
 
 The boy had traveled to Guinea to attend the funeral of one of the outbreak's earlier victims. 
 
 Kargbo said a medical team had been sent to Buedu to test those who came into contact with the boy before his death. 
 
 "HIGHLY CONTAGIOUS" 
 
 The international medical charity Medecins Sans Frontieres (MSF) announced on Saturday it was reinforcing its medical and logistics teams in Guinea in response to the epidemic. 
 
 It is also flying in 33 metric tons of medicines and equipment and is setting up isolation units in the three affected towns in Guinea. 
 
 "These structures are essential to prevent the spread of the disease, which is highly contagious," Dr. Esther Sterk, MSF's tropical medicine adviser, said in a statement. "Specialised staff are providing care to patients showing signs of infection." 
 
 Ebola is introduced into the human population through close contact with infected animals including chimpanzees, gorillas, fruit bats, monkeys, forest antelope and porcupines, according to the WHO. 
 
 The disease, which is transmitted between humans through contact with organs, blood, secretions, or other bodily fluids, is most commonly found in the Democratic Republic of Congo, Uganda, South Sudan and Gabon. 
 
 Though no epidemics of the disease have been recorded among humans in West Africa, a variety of Ebola infected a colony of chimpanzees in Ivory Coast's Tai National Park, near the country's border with Liberia, in 1994. 
 
 A Swiss scientist, who performed an autopsy on one of the infected animals, contracted the disease but later recovered. 
 
 (Additional reporting by Umaru Fofana in Freetown; Writing by Joe Bavier; Editing by Kevin Liffey and Eric Walsh)
– The Ebola outbreak that's claimed at least 500 lives in West Africa may have been lurking a while before going on its killing spree, NBC News reports. Researchers figured this by studying blood samples from old cases of viral illnesses in Liberia, Sierra Leone, and Guinea, and finding possible signs of Ebola. The results aren't 100%—the samples were old, after all—but evidence suggests that an Ebola outbreak could be spotted ahead of time. "It makes us realize that you don’t have to see an outbreak" to know it's there, said Randal Schoepp, a US Army researcher. "In Africa, it is easy for a disease to smolder because there is so much disease." This is Ebola's first outbreak in West Africa, but other dangerous diseases like dengue, malaria, and particularly Lassa fever are common there. Lassa fever also comes with Ebola-like symptoms such as internal and external bleeding, vomiting, and high fever. Analyzing 253 blood samples from 2006 to 2008, Schoepp's crew found that almost 9% of samples cleared of other ailments tested positive for Ebola antibodies. Another challenge is educating West Africans about Ebola, for odd rumors are spreading there—like the notion that Nescafe can cure it when mixed with sugar and coca, the Washington Post reports. But Susan Sered writes at Salon that the biggest challenge may be educating Americans, who could easily afford to "support local governments in building functioning public health infrastructures." (Read about Guinea's rather odd means of curbing Ebola.)