Sudan ebolavirus is a species of ebolavirus that causes Ebola virus disease in humans, characterized by severe hemorrhagic fever and a high case fatality rate, though typically lower than that of Zaire ebolavirus.
Explanation
Sudan ebolavirus (species Sudan ebolavirus) is one of several members of the genus Ebolavirus within the family Filoviridae. Its genome is a negative‑sense, non‑segmented single‑stranded RNA of approximately 19 kilobases encoding the nucleoprotein, VP35, VP40, glycoprotein, VP30, VP24 and polymerase proteins. The virions are filamentous and enveloped. Sudan ebolavirus was first identified in 1976 during an outbreak of hemorrhagic fever in Nzara and Maridi, southern Sudan (now South Sudan), occurring concurrently with an outbreak caused by Zaire ebolavirus in what is now the Democratic Republic of the Congo. A second outbreak in Sudan in 1979 confirmed the virus as a distinct species. Natural reservoirs have not been definitively identified, but fruit bats are considered likely hosts. The virus infects monocytes, macrophages and dendritic cells, triggering a dysregulated immune response that results in vascular leakage and multi‑organ involvement. Reported case fatality rates for Sudan ebolavirus outbreaks range from 25 % to 65 %, somewhat lower than those of Zaire ebolavirus. There is no approved vaccine for Sudan ebolavirus, though several candidate vaccines and monoclonal antibody therapies are under development.
Historical Outbreaks and Response
Sudan ebolavirus has caused multiple human outbreaks in East Africa. Aside from the initial 1976 and 1979 events in southern Sudan, significant outbreaks occurred in Gulu, Uganda in 2000–2001, infecting over 400 people and killing more than 200. Smaller outbreaks followed in Yambio, Sudan in 2004 and in Uganda in 2011 and 2012. A resurgence in 2022 in central Uganda prompted renewed international response. Human‑to‑human transmission occurs through direct contact with blood or bodily fluids of infected individuals, particularly in healthcare settings and during traditional burial practices. Infection control measures, barrier nursing, contact tracing and community education are essential for containment. Supportive care remains the mainstay of treatment, focusing on hydration, electrolyte balance and management of complications. In the absence of a licensed vaccine, ring vaccination strategies using Zaire ebolavirus vaccines are not applicable; however, experimental vaccines targeting the Sudan strain are undergoing clinical evaluation.
Sudan ebolavirus causes severe disease in humans but is less lethal than Zaire ebolavirus. Ongoing research into reservoir hosts, vaccine development and therapeutic countermeasures is crucial to mitigate future outbreaks.
Related Terms: Zaire Ebolavirus, Bundibugyo Ebolavirus, Taï Forest Ebolavirus, Reston Ebolavirus, Marburg virus