The largest known outbreak of the lethal Ebola virus in West Africa is prompting authorities as far away as Asia to take preventive measures, although scientists say a global spread of the disease is unlikely. At South Korea's Incheon International airport, a major hub for air travel in Asia, quarantine inspections of arriving passengers are being enhanced. Authorities say all passengers are being recorded by an infrared camera to detect fevers because Ebola is becoming a big concern. The incubation period of the Ebola virus is between two and 21 days, during which time an infected person might not show any signs of infection. In Hong Kong, the Center for Health Protection says public hospitals will begin to report and test all those who developed fever who, within the past 21 days, traveled to the three affected African countries. Singapore's health ministry is urging the public there "not to be alarmed." It has issued a statement deeming Ebola to pose "a low public health risk to Singapore," in part because "there is low travel connectivity to West Africa where the current outbreak remains limited to." Some airlines have suspended flights into the affected region. But health authorities say there is little risk of passengers contracting the virus on a flight from an infected person.Dr. Day, a tropical medicine researcher, explains Ebola is only spread through direct contact with blood, saliva and other bodily fluids. Since March, there have been more than 1,200 confirmed Ebola cases in West Africa. This is believed to be a new strain of the virus and nearly 700 of those infected in this worst-known outbreak have died.There is no known cure for Ebola. It was first recognized in Zaire (now the Democratic Republic of Congo) in 1976. There is no approved vaccine, but at least four are under development. According to the passage, which of the following about Ebola virus is true?
It has become a global spread. people show some signs of infection once infected. It is only spread through direct contact with blood, saliva and other bodily fluids. There are at least four approved vaccines for it now.