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Four of the six known ebolaviruses, including EBOV, cause a severe and often fatal hemorrhagic fever in humans and other mammals, known as Ebola virus disease (EVD).
Ebola virus has caused the majority of human deaths from EVD, and was the cause of the 2013-2016 epidemic in western Africa, which resulted in at least 28,646 suspected cases and 11,323 confirmed deaths.
Ebola virus and its genus were both originally named for Zaire (now the Democratic Republic of the Congo), the country where it was first described, and was at first suspected to be a new strain of the closely related Marburg virus.
The virus was renamed Ebola virus in 2010 to avoid confusion. Ebola virus is the single member of the species Zaire ebolavirus, which is assigned to the genus Ebolavirus, family Filoviridae, order Mononegavirales. The members of the species are called Zaire ebolaviruses.
The natural reservoir of Ebola virus is believed to be bats, particularly fruit bats, and it is primarily transmitted between humans and from animals to humans through body fluids.
The EBOV genome is a single-stranded RNA, approximately 19,000 nucleotides long. It encodes seven structural proteins: nucleoprotein (NP), polymerase cofactor (VP35), (VP40), GP, transcription activator (VP30), VP24, and RNA-dependent RNA polymerase (L).
Because of its high fatality rate (up to 83 to 90 percent), EBOV is also listed as a select agent, World Health Organization Risk Group 4 Pathogen (requiring Biosafety Level 4-equivalent containment), a US National Institutes of Health/National Institute of Allergy and Infectious Diseases Category A Priority Pathogen, US CDC Centers for Disease Control and Prevention Category A Bioterrorism Agent, and a Biological Agent for Export Control by the Australia Group.
More information: CDC
EBOV carries a negative-sense RNA genome in virions that are cylindrical/tubular, and contain viral envelope, matrix, and nucleocapsid components.
Each virion contains one molecule of linear, single-stranded, negative-sense RNA, 18,959 to 18,961 nucleotides in length. The 3′ terminus is not polyadenylated and the 5′ end is not capped. This viral genome codes for seven structural proteins and one non-structural protein. The gene order is 3′–leader–NP–VP35–VP40–GP/sGP–VP30–VP24–L–trailer–5′; with the leader and trailer being non-transcribed regions, which carry important signals to control transcription, replication, and packaging of the viral genomes into new virions. Sections of the NP, VP35 and the L genes from filoviruses have been identified as endogenous in the genomes of several groups of small mammals.
Ebola virus is a zoonotic pathogen. Intermediary hosts have been reported to be various species of fruit bats... throughout central and sub-Saharan Africa. Evidence of infection in bats has been detected through molecular and serologic means. However, ebolaviruses have not been isolated in bats.
End hosts are humans and great apes, infected through bat contact or through other end hosts. Pigs in the Philippines have been reported to be infected with Reston virus, so other interim or amplifying hosts may exist.
Ebola virus outbreaks tend to occur when temperatures are lower and humidity is higher than usual for Africa. Even after a person recovers from the acute phase of the disease, Ebola virus survives for months in certain organs such as the eyes and testes.
Zaire ebolavirus is one of the four ebolaviruses known to cause disease in humans. It has the highest case-fatality rate of these ebolaviruses, averaging 83 percent since the first outbreaks in 1976, although a fatality rate of up to 90 percent was recorded in one outbreak in the Republic of the Congo between December 2002 and April 2003. There have also been more outbreaks of Zaire ebolavirus than of any other ebolavirus.
More information: WHO
that is being attacked by billions of bacteria
whose numbers double every forty years.
Either the host dies, or the virus dies, or both die.
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