Ebola Outbreak Traced to Boy, 2 NC to 'quarantine' returning missionaries By Rob Quinn, Newser Staff Posted Aug 11, 2014 5:35 AM CDT Updated Aug 11, 2014 6:14 AM CDT 11 comments Comments A large billboard promotes the washing of hands to prevent the spread of the deadly Ebola virus in Monrovia, Liberia. (AP Photo/Jonathan Paye-Layleh) (Newser) – Scientists trying to figure out how the Ebola outbreak in West Africa became the deadliest ever have traced the outbreak to a 2-year-old boy in Guinea believed to have died from the disease late last year. It's not clear how the little boy became infected last December, though researchers believe the culprit could have been contaminated fruit, a dirty needle, or contact with fruit bats, which carry the disease but do not die from it, reports the New York Times. Researchers say the case fits the subsequent pattern of transmission, though there may have been even earlier, unknown cases. In other developments: Sierra Leone and Liberia have both declared states of emergency, deployed troops to combat the outbreak, and warned against public gatherings, but Sunday services in both countries were packed yesterday, Reuters reports. Preachers branded the disease the work of Satan and urged worshippers to obey the instructions of health workers. Missionaries who worked with Ebola patients in Liberia are to be quarantined on their return to the US, NBC reports. North Carolina–based aid agency SIM USA says its workers will be quarantined for 21 days—the longest known Ebola incubation period. Health officials say the missionaries will be allowed to go home, but they will be asked to limit their contact with other people. The measure is being taken "out of an abundance of caution, and it is important to remember that there are no confirmed or suspected cases of Ebola in North Carolina," the medical director of Mecklenburg County said in a statement. In Spain, health officials say they have obtained experimental Ebola drug ZMapp to treat a 75-year-old priest who caught the virus in Liberia and has been brought to a Madrid hospital, the AP reports. Two Americans treated with the drug are now in an Atlanta hospital, and Dr. Kent Brantly says he is growing stronger every day.