Global health experts are striving to identify a mysterious illness in Liberia that has already killed 12 people. Officials with the World Health Organization in Monrovia have already ruled out Ebola, yellow fever and a regional virus called Lassa. They have sent samples to the U.S. Centers for Disease Control and Prevention in Atlanta for further tests. The illness causes fever, vomiting, diarrhea and headaches. At least 21 cases have been confirmed so far and nearly all of the victims had attended the funeral of a religious leader last month in Sinoe County. The health experts are looking for a link between the victims and food and drinks they may have consumed at the funeral.