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- Peter Piot
ebolavirus
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What is ebolavirus?
Ebolavirus is a genus of viruses within the Filoviridae family. Certain types of ebolavirus are especially deadly to humans and nonhuman primates, causing Ebola virus disease (EVD), also known as Ebola hemorrhagic fever, in humans. EVD is characterized by fever, rash, vomiting, diarrhea, and hemorrhaging.
Named after the Ebola River where they first appeared in 1976, ebolaviruses are related to the Marburgvirus genus. The five species of ebolaviruses include Zaire ebolavirus (EBOV), Sudan ebolavirus (SUDV), Taï Forest ebolavirus (TAFV), Reston ebolavirus (RESTV), and Bundibugyo ebolavirus (BDBV). EBOV is the most lethal, with a fatality rate between 50 and 90 percent. Fruit bats are suspected as a natural reservoir of the viruses.
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What type of virus is ebolavirus?
Ebolavirus is a genus of viruses within the family Filoviridae. Filoviruses are known for their thread-like appearance and are composed of a protein shell, or capsid, enclosing viral nucleic acids. The ebolavirus genome consists of a single strand of negative-sense RNA.
There are five identified species of ebolavirus: Zaire ebolavirus, Sudan ebolavirus, Taï Forest ebolavirus, Reston ebolavirus, and Bundibugyo ebolavirus. These viruses are responsible for Ebola virus disease (EVD) in humans and nonhuman primates, with some strains causing fatality in 50 to 90 percent of victims. Fruit bats are suspected as a natural reservoir of ebolaviruses.
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Where is ebolavirus commonly found?
Ebolavirus was first discovered in 1976 near the Ebola River in central Africa. The most severe outbreak occurred in western Africa in 2014.
There are five known species of ebolavirus, named after their outbreak locations: Zaire ebolavirus, Sudan ebolavirus, Taï Forest ebolavirus, Reston ebolavirus, and Bundibugyo ebolavirus. While most ebolavirus outbreaks have occurred in central Africa, the Reston ebolavirus was first discovered in laboratory monkeys in Reston, Virginia, in 1989. The monkeys were traced to an export facility in the Philippines. Fruit bats are suspected carriers of ebolaviruses.
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What are some symptoms caused by an ebolavirus infection?
Ebolavirus infections typically manifest between 2 to 21 days following exposure. The onset is abrupt and marked by symptoms such as fever, intense headaches, muscle soreness, and appetite loss. Within days, the virus triggers disseminated intravascular coagulation, leading to blood clots and hemorrhaging, especially in internal organs.
Additional symptoms include nausea, bloody vomiting and diarrhea, conjunctivitis, and sore throat. A rash may appear on the trunk, spreading rapidly. Spontaneous bleeding from orifices, skin breaks, and internal organs can occur. Death often results from hemorrhaging, shock, or kidney failure within 8 to 17 days. Some survivors experience post-Ebola syndrome, with symptoms like vision problems, severe pain, and fatigue.
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How can ebolavirus outbreaks be controlled and prevented?
To control and prevent ebolavirus outbreaks, proven strategies include barrier nursing, handling infected materials in isolated labs, and decontaminating equipment. Experimental vaccines, such as VSV-EBOV, have shown promise in preventing the virus's spread among those in close contact with infected individuals.
During outbreaks, identifying and isolating cases, combined with tracing contacts, proves most effective in stopping the spread. Implementing strict infection control measures, providing protective equipment for healthcare workers, and ensuring safe burial practices are also vital. Vaccination with rVSV-ZEBOV can help prevent transmission and facilitate outbreak control for those at risk.
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ebolavirus, genus of viruses in the family Filoviridae, certain members of which are particularly fatal in humans and nonhuman primates. In humans, ebolaviruses are responsible for Ebola virus disease (EVD), an illness characterized primarily by fever, rash, vomiting, diarrhea, and hemorrhaging. The name given to the viruses and the disease they cause is derived from the Ebola River, a tributary of the Congo River in central Africa, where the majority of EVD epidemics have occurred. The most severe outbreak on record was the Ebola outbreak of 2014, which devastated communities in western Africa, however. There are five species of ebolaviruses: Zaire ebolavirus, Sudan ebolavirus, Taï Forest ebolavirus, Reston ebolavirus, and Bundibugyo ebolavirus. The viruses representative of those species are commonly referred to as Ebola virus (EBOV), Sudan virus (SUDV), Taï Forest virus (TAFV), Reston virus (RESTV), and Bundibugyo virus (BDBV), respectively.
Ebolaviruses are typical filoviruses, having filamentous (threadlike) virion particles, sometimes branching, circular, rod-shaped, or U-shaped in form. Virions measure about 80 nanometres in diameter and are tubular, with their central channel housing a helical nucleocapsid, which contains the negative-strand RNA ebolavirus genome. Surrounding the nucleocapsid is an outer lipid envelope made from the membrane of the host cell. The virion’s outer surface is covered with globular spikes, which are formed from glycoprotein, one of the virion’s seven structural proteins and the only one of its proteins to be expressed on the outer surface. Glycoprotein allows the virion to attach to a receptor on the host cell surface and thereby fuse with the host cell membrane, leading to infection. The ebolavirus genome is approximately 19 kilobases in length.
The extensive tissue injury documented in ebolavirus infection, including massive cell death and hemorrhage, has been associated with viral interference of immune cell function, particularly suppressive effects on the maturation of dendritic cells and the catastrophic loss (via apoptosis) of lymphocytes. Those effects have been linked in turn to uncontrolled viral replication and the release of pro-inflammatory molecules and substances that alter the function of blood vessels. The virus eventually disseminates to the cells of major organs, causing severe tissue damage.
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EBOV is the deadliest of the ebolaviruses, with a case fatality rate of between 50 and 90 percent. It was discovered from an outbreak of hemorrhagic disease that occurred in Zaire (later the Democratic Republic of the Congo) in 1976. That same year an outbreak of a similar illness was reported in Sudan, leading to the discovery of SUDV. In 1989 cynomolgus macaques that had been imported into the United States from the Philippines were found to be infected with a filovirus, leading to the identification of RESTV; RESTV was the first ebolavirus to be detected outside Africa. TAFV was identified from a case of denguelike illness that occurred in 1994 in a researcher who had conducted an autopsy on a chimpanzee that died from a hemorrhagic disease in Taï National Park, Côte d’Ivoire. BDBV was described in 2007 from an outbreak of hemorrhagic fever in Uganda’s Bundibugyo district.
Fruit bats are a suspected wild reservoir of ebolaviruses, and the spatial and temporal distribution of infected bats has been found to be coincident with Ebola outbreaks in human populations.