reaks, several researchworkers became infected with the virus, but did not become ill. Ebola HF typically appears in sporadic outbreaks, usually spread within a health-care setting (a situation known as amplification). It is likely that sporadic, isolated cases occur as well, but go unrecognized.How is Ebola virus spread? Infection with Ebola virus in humans is incidental -- humans do not "carry" the virus. Because the natural reservoir of the virus is unknown, the manner in which the virus first appears in a human at the start of an outbreak has not been determined. However, researchers have hypothesized that the first patient becomes infected through contact with an infected animal. After the first case-patient in an outbreaksetting (often called the index case) is infected, the virus can be transmitted in several ways. People can be exposed to Ebola virus from direct contact with the blood and/or secretions of an infected person. This is why the virus has often been spread through the families and friends of infected persons: in the course of feeding, holding, or otherwise caring for them, family members and friends would come into close contact with such secretions. People can also be exposed to Ebola virus through contact with objects, such as needles, that have been contaminated with infected secretions. Nosocomial transmission frequently has been associated with outbreaks of Ebola HF. Nosocomial spread includes both types of transmission described above, but the term is used to describe the spread of disease in a health-care setting such as a clinic or hospital. In African health-care facilities, patients are often cared for without the use of a mask, gown, or gloves, and exposure to the virus has occurred when health care workers treated individuals with Ebola HF without wearing these types of protective clothing. In addition, when needles or syringes are used, they may not be of the disposable type, or may not have been sterili...
