Summary:In March 2014, an outbreak of Ebola Virus Disease (EVD) began in Guinea. It spread to Liberia in the same month and to Sierra Leone a month later. In Nigeria, an outbreak in July linked to a traveler from Liberia was contained. In August, a case was detected and contained in Senegal. The current EVD outbreak is the largest, most persistent one ever documented, and is the first to occur in West Africa. As of October 12, 2014, nearly 9,000 people had contracted EVD, of which nearly 4,500 had died. There have been 17 medical evacuations of international medical workers to developed countries infected in Guinea, Liberia, or Sierra Leone (the âaffected countriesâ). Until October, all EVD cases outside of West Africa were among medical evacuees. In that month, the United States and Spain experienced their first secondary cases, which occurred in health workers who had cared for EVD patients. Prior human EVD outbreaks occurred primarily in rural and forested areas of Central and East Africa. The current outbreak is occurring in both urban and rural areas. Its current size and rate of growth is widely viewed as a potential threat to other African countries and the world. Due to weak surveillance systems, there is uncertainty about the actual number of EVD cases in West Africa. The Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) both assert that EVD cases are underreported. Actual cases could be two to four times larger than reported, according to WHO. The CDC estimates that cases are doubling every 15-40 days in Liberia and Sierra Leone. Without additional interventions and sufficient patient isolation in EVD treatment units (ETUs), the CDC estimates that up to 1.4 million people could contract Ebola in the two countries by early 2015. The CDC also asserts that 70% of patients must be isolated in ETUs in order for the epidemic to decrease and eventually end.
