Ebola: Basics About the Disease (CRS Report for Congress)
| Release Date |
Oct. 3, 2014 |
| Report Number |
R43750 |
| Report Type |
Report |
| Authors |
Sarah A. Lister, Specialist in Public Health and Epidemiology |
| Source Agency |
Congressional Research Service |
Summary:
Will be suppressed. In March 2014, global health officials recognized an outbreak of Ebola virus disease (EVD) in Guinea, West Africa. In retrospect, officials determined that the outbreak began in December 2013, and spread to the adjacent countries of Liberia and Sierra Leone. In September 2014, the U.S. Centers for Disease Control and Prevention (CDC) confirmed the first EVD case diagnosed in the United States, heightening concerns among some who fear the disease could spread in American communities. This report discusses EVD in general, including symptoms, modes of transmission, incubation period, and treatments; presents projections of the future course of the outbreak; and lists additional CRS products, including products focused on the situation in West Africa. Unless otherwise cited, information in this report is drawn from Ebola information pages of CDC and the World Health Organization (WHO).
In humans EVD has an incubation periodâthe time between exposure and onset of symptomsâfrom 2 to 21 days, with an average of 8 to10 days.
Isolation is used to separate ill persons who have a contagious disease from others. It is often carried out in a healthcare setting.
Quarantine is used to separate and restrict the movement of well persons who may have been exposed to a contagious disease to see if they become ill. It is often carried out at home.
The case fatality rate (CFR), the percentage of infected individuals who do not survive, generally exceeds 50%, an extraordinarily high rate among infectious diseases. The true CFR is an inherent property of the infectious agent (in this case, the Ebola Zaire virus).
Prevention of human-to-human transmission of Ebola virus requires avoiding contact with body fluids of those who are sick. EVD is not likely to be easily transmitted in community settings in the United States. However, caregivers, including family members and healthcare workers, face considerable risk of transmission. Barrier protections (called personal protective equipment or PPE), liberal disinfection of premises and facilities housing EVD patients, and careful handling of human remains and contaminated objects are essential.
No specific therapy or vaccine against EVD is approved by the U.S. Food and Drug Administration (FDA) for use in the United States, or is available elsewhere in the world. However, for more than a decade the U.S. government has funded research and development of specific therapies (such as antiviral drugs) and vaccines against EVD for military force protection and domestic biodefense purposes.
CDC authors published outbreak projections for Liberia and Sierra Leone. The model found that without further interventions to slow the outbreak (a worst case scenario), the case count in the two countries could reach 1.4 million by January 20, 2015. Conversely, if 70% of EVD patients were effectively isolated going forward, the outbreak in both countries would be almost controlled by that same date.
