7 Ebola from emergence to epidemic: the virus and the disease, global preparedness and perspectives

Humans constantly encounter threats from many infectious, zoonotic, and devastating pathogens. Outbreaks of severe acute respiratory syndrome (SARS), bird flu, and swine flu posing pandemic threats have compelled health agencies to follow global preparedness for combating the emerging deadly pathogens. The outbreak in West Africa of highly contagious Ebola viral disease (EVD) that started in Guinea in December 2013, assumed global proportions to become the largest outbreak of EVD and the most prominent international health concern. With fatality rates of nearly 50%-90%, it has claimed, as of 11 April 2015, 10,619 human lives out of a total of 25,626 cases reported worldwide. Ebola virus (EBOV), a member of Filoviridae family, is associated with severe, often lethal, hemorrhagic fever disease in humans and animals. The animal hosts, including non-human primates and reservoir hosts (fruit bats), play a significant role in transmission and maintenance of EBOV in nature. Although no approved vaccine for the prevention of EVD currently exists, disease control can be greatly enhanced by timely laboratory confirmation through blood tests using enzyme-linked immunosorbent assay (ELISA) and reverse transcription polymerase chain reaction (RT-PCR). Adherence to strict sanitary and hygienic measures, monitoring and surveillance of EBOV, as well as quarantine checks on international trade, transport, and visitors from affected countries are mandatory to prevent and control the spread of EVD. This review describes the salient properties of EBOV and the development of novel diagnostics, vaccines, and control strategies for this emerging disease of high public health concern and international emergency.