Ebola outbreaks typically appear sporadically. Confirmed cases have been reported in:
- The Democratic Republic of the Congo
- The Ivory Coast
In the United States, there have been no reported cases of Ebola virus in humans. Ebola-Reston virus caused severe illness and death in monkeys imported to research facilities in the United States and Italy from the Philippines; during these outbreaks, several research workers became infected with the virus, but did not become ill.
Just as scientists are unsure of the animal host for the Ebola virus, they are also unsure how an outbreak occurs; however, researchers have hypothesized that the first patient with Ebola becomes infected with the virus through contact with an infected animal.
Once transmission of Ebola virus occurs to the first human, scientists do know that transmission of Ebola occurs through direct contact with infected people, or direct contact with their body fluids (such as blood or secretions). Transmission occurs most often when an infected person is in the late stages of the illness.
In the aftermath of the events of September and October 2001, there is heightened concern that the Ebola virus might be used as an agent of bioterrorism. The deliberate release of the virus is now regarded as a possibility, and the United States is taking precautions to deal with this.
The Centers for Disease Control and Prevention (CDC) considers the Ebola virus a Category A agent. Category A agents are believed to present the greatest potential threat for harming public health, and have a moderate to high potential for large-scale dissemination (spread). The public is generally more aware of Category A agents, and broad-based public health preparedness efforts are necessary. Other Category A agents are: