Investigators believe the first victim of Ebola in any outbreak acquires the disease after coming into contact with a "reservoir," an infected animal that is often a monkey.
"Whenever there is contact between man and the reservoir of Ebola then you get the first case," said Miriam Nanyunja of the World Health Organization.
Ebola was first reported in 1976 in Congo and is named for the river where it was recognized. There is no cure or vaccine for it. Ebola is "characterized by fever, headache, joint and muscle aches, sore throat, and weakness, followed by diarrhea, vomiting, and stomach pain. A rash, red eyes, hiccups and internal and external bleeding may be seen in some patients," according to a factsheet by the U.S.-based Centers for Disease Control and Prevention.
The virus can be transmitted through direct contact with the blood or secretions of an infected person, or objects that have been contaminated with infected secretions. During communal funerals, for example, when the bereaved come into contact with an Ebola victim, the virus can be contracted, officials said, warning against unnecessary contact with suspected cases of Ebola.
Nanyunja of WHO said Ugandans near the Ebola epicenter should practice what she called "social distancing," avoiding things such as handshakes and similar contact.