Louis, mo 63110, usa 3 3 center for microbial pathogenesis, georgia state university, atlanta ga 30303, usa 4 4 united states army medical research institute of infectious diseases, frederick, md 21702, usa 5 5 the university of. These viruses differ in their virulence for humans. Pdf ebola virus disease, management, and prevention. The virus is a member of the filoviridae family genus ebolavirus. The taxonomy of ebolaviruses has been modified several times since their. The viruses that cause evd are located mainly in subsaharan africa. Ebola, the killer virus infectious diseases of poverty.
Using timedependent parameters, we incorporate the increasing intensity of intervention efforts. A previous study by mcelroy et alin 4 ebolavirusdisease survivors demonstrated that there were activated. Primary outcome was death or discharge after transfer to ebola. Ebola virus disease evd, one of the deadliest viral diseases, was discovered in 1976 when two consecutive outbreaks of fatal hemorrhagic fever occurred in different parts of central africa. Ebov, is one of six known species within the genus ebolavirus.
Zaire ebolavirus ebov has a fatality rate of up to 90% in humans and the viral dsrna is sensed by rigi to activate innate immune responses habjan et al. Ebola classification and taxonomy ebola sudan, ebola zaire, ebola cote divoire, and ebola reston are the four known strains subtypes of ebola. Transmission dynamics and final epidemic size of ebola. Events in liberia drew widespread attention to ebola as a threat to global health security including urbanization of the disease. Additional cases in may and june heralded the countrys severe outbreak. International committee on taxonomy of viruses ictv, the name of the genus ebolavirus. Ebola virus disease is one of the most deadly ailments known to mankind. A scanning electron microscograph of ebola virus particles blue budding from an infected grivet chlorocebus aethiops linnaeus, 1758 vero e6 cell. Ana virus abbreviations, achieves of virology, vol. We propose a compartmental model for evd dynamics, including virus transmission in the community, at hospitals, and at funerals. Once the more virulent forms enter the human population, transmission occurs primarily through contact with infected body fluids and can result in major epidemics in underresourced settings. Tai forest ebolavirus, sudan ebolavirus sudv, zaire ebolavirus ebola virus, ebov, bundibugyo ebolavirus bundibugyo virus and reston ebolavirus reston virus, restv. Ebola virus disease evd is a rare and deadly disease in people and nonhuman primates.
Virus metadata resource vmr the vmr provides a list of exemplar viruses for each species recognized by the ictv and links to their genomic sequence. Four species of ebolaviruses have been identified in west or equatorial africa. Now if you look into these publications you will see that the majority of them actually addresses what is now again called ebola virus namely the entity discovered in zaire in 1976 by karl johnson. Ebola virus outbreak, updates on current therapeutic.
Ebola, also known as ebola virus disease evd, is a viral haemorrhagic fever of humans and other primates caused by ebolaviruses. As of the end of march 2016, the west africa epidemic of ebola virus disease ebola had resulted in a total of 28,646 cases, 11,323 of them fatal, reported to the world health organization. Reston virus was first described in 1990 as a new strain of ebola virus ebov. The current taxonomy has only been partially accepted by most laboratory virologists.
The continued spread is facilitated by insufficient medical facilities, poor sanitation, travel, and unsafe burial practices. In liberia, ebola virus disease was first reported from lofa county on march 30, 2014, a week after cases in guinea had been reported figure 1. An epidemic of ebola virus disease is occurring in western africa on a scale not seen before, particularly in the countries of guinea, liberia, and sierra leone. Ebola virus disease evd has mostly affected economically deprived countries as limited resources adversely affect a countrys infrastructure and administration. Guinea and liberia, the first nations affected by the outbreak, have put in place measures to contain the spread, supported by international organizations. Environmental changes caused by humans can drive the emergence of infectious diseases throughout the world daszak et al.
Two epidemics occurred almost simultaneously in zaire and sudan, killing almost 500 people. A virus of the species reston ebolavirus is a reston virus restv if it has the properties of reston ebolaviruses and if its genome diverges from that of the prototype reston virus. Ebola virus, ebola virus diseases, hemorrhagic fever, west africa ebola outbreak 1. The largest outbreak of ebola virus disease began in guinea in december 20 and was caused by the zaire ebolavirus footnote 14. B transmission electron microscograph of ebola virus particles blue found both as extracellular particles and budding particles from infected vero e6 cells. This is an open access article distributed under the terms of the creative. Ebola virus disease 202014 outbreak in west africa. Ebolavirus classification based on natural vectors ncbi. The genera ebolavirus and marburgvirus were originally classified as the species of the nowobsolete genus filovirus. Although agents that cause viral hemorrhagic fever syndrome constitute a geographically diverse group of viruses, all of those identified to date are rna viruses with a lipid envelope, all are considered zoonoses, all damage the microvasculature resulting in. While the case fatality from ebola virus disease evd has been estimated to be as high as 80% based on previous smaller outbreaks, the who reported an overall case fatality of around 65% in the west african outbreak. In 2014 and 2015, the largest ebola virus disease evd outbreak in. Ebola and marburg are the only members of the filovirus family. The 20 2015 zaire ebolavirus ebov epidemic in west africa infected more than 28 000 people, with over 50% of cases occurring within sierra leone.
Pdf ebola virus was first discovered in 1976,who reports 24 outbreaks,28,633 cases and 11,315 deaths in the recent outbreak. The 2014 2015 ebola epidemic in west africa was unprecedented. However, its high casefatality rate, potential for humantohuman transmission and propensity to be associated with hospitalbased transmission is both concerning and a fertile source for hysteria 31,32. For example, there exists reston virus variant pennsylvania restvpen, differing by less than 10% at the nucleotide level. Human activities link fruit bat presence to ebola virus. An epidemic of ebola virus disease is occurring in western africa on a scale not seen before, particularly in the. Apr 09, 2019 ebola virus, formally called zaire ebolavirus, is a rare virus that infects humans and nonhuman animals such as pigs and other primates. Ebola virus is negativesense rna virus with a nonsegmented genome similar to that of rsv and niv. Ebola virus is a hemorrhagic fever virus in the filoviridae family. One expatriate healthcare worker presented with ebola virus meningoencephalitis rtpcr of csf and plasma were positive for ebola virus 9 months after recovering from severe primary ebola virus disease in 2015.
Virus names are written in lower case except if a name compound is a proper noun e. This genus was introduced in 1998 as the ebolalike viruses. On may 9, 2015, the world health organization declared liberia free of ebola, 42 days after safe burial of the last known casepatient. The first cases were recorded in guinea in december 20. Reston virus restv is one of six known viruses within the genus ebolavirus.
Patients with the disease, which appeared first in southern sudan in june 1976, presented with influenzalike symptoms including headache, fever, and myalgias and rapidly progressed to a more severe illness characterized by diarrhea, vomiting, chest pains, and hemorrhage. History of ebola virus disease error processing ssi file. The first outbreak occurred in the democratic republic of congo formerly zaire in a village near the ebola river, which gave the virus its name. Following the successful efforts to wipe out the virus of smallpox variola virus that started in the 1950s and officially realized their goal in 19803, the world health organization who made a commitment in 1988 to eradicate poliovirus and poliomyelitis and achieve a poliofree world by 2000. Ebola, also known as ebola hemorrhagic fever or ebola viral disease, is a rare and deadly illness caused by one of the strains of ebola virus. As of 20 february 2020 the outbreak is still ongoing. Members of the family filoviridae produce variously shaped, often filamentous, enveloped virions containing linear nonsegmented, negativesense rna genomes of 1519 kb. The genus ebolavirus is a virological taxon included in the family filoviridae filamentshaped. Classification of the filoviridae family will most probably continue to develop as further information becomes available. It is also the secondbiggest ebola epidemic ever recorded, behind the west africa outbreak of 20142016. Kuhn, md, phd, phd, ms virology lead, nihniaid integrated research facility at fort detrick irffrederick, frederick.
Prabhakar1,4 1department of microbiology and immunology, university of illinois college of medicine, chicago, il, usa 2department of medicine, university of illinois college of medicine, chicago, il, usa 3department of emergency medicine, university of illinois. Ebola virus disease in children, sierra leone, 20142015. On 1 august 2018, the democratic republic of the congo ministry of health declared an outbreak when 4 individuals tested positive for the ebola virus. The ebola virus epidemic burst in west africa in late 20, started in guinea, reached in a few months an alarming diffusion, actually involving several countries liberia, sierra leone, nigeria, senegal, and mali. The genus ebolavirus contains five species with the taxonomic. Prince leopold institute of tropical medicine, antwerp, belgium. Ebola virus infection complications bmj best practice. Reston virus causes ebola virus disease in nonhuman primates. In zaire, an outbreak at a local hospital, possibly due to contaminated hypodermic needles, exhibited an 88% mortality rate for those infected.
The known species within the genus ebolavirus are bundibugyo, sudan. Thirtyfour outbreaks have been reported in africa since it was first. Hundreds of health workers died, decimating the alreadystruggling healthcare systems of liberia, guinea and sierra leone. This discussion leads us to the important difference between a virus and a species a virus species is defined as a polythetic class of viruses that constitutes a replicating lineage and occupies a particular ecological niche. The 2014 2015 ebola virus disease outbreak and primary healthcare delivery in. Ebola virus disease evd is a lifethreatening viral disease with a fatality rate ranging from around 30% to 90%. Ebola virus, formally called zaire ebolavirus, is a rare virus that infects humans and nonhuman animals such as pigs and other primates. Every page goes through several hundred of perfecting techniques. Review ebola virus outbreak, updates on current therapeutic strategies hatem a. Zaire ebolavirus with type virus ebola virus ebov, bundibugyo ebolavirus with type virus bundibugyo virus bdbv, reston ebolavirus with type virus reston virus restv. In march 1998, the vertebrate virus subcommittee proposed in the international committee on taxonomy of viruses ictv to change the genus filovirus to the family filoviridae with two specific genera. Introduction ebola virus disease evd is one of the deadliest haemorrhagic fevers affecting humans and nonhuman primates. 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. See clinical manifestations and diagnosis of ebola virus disease and.
Of these, only four ebola, sudan, tai forest, and bundibugyo viruses are known to cause disease in people. The western african ebola virus epidemic 202016 was the most widespread outbreak of ebola virus disease evd in historycausing major loss of life and socioeconomic disruption in the region, mainly in guinea, liberia and sierra leone. According to the ictv rules of nomenclature, virus species names are italicized with the first letter of the name capitalized zaire ebolavirus. The ebola virus ebov strains were first identified in africa in 1976. Center for disease control, atlanta, georgia 30333, usa.
Temporal and spatial analysis of the 20142015 ebola virus outbreak in west africa. Ebolaviruses belong to the filoviridae family and ebolavirus genus in the baltimore v classification system. Several patients diagnosed with ebola virus disease in africa have been evacuated to the united states for. The 2014 ebola virus disease evd outbreak in west africa was the largest and longest ever reported since the first identification of this disease. The severe epidemic of ebola virus disease in liberia started in march 2014. The first evd outbreak was reported in the 1970s in zaire now the democratic. For the viruses of the family of filoviridae, both genus label classification and. J global infect dis serial online 2014 cited 2015 mar 1. It is one among several viruses within the genus ebolavirus. Five distinct species of ebola virus have been isolated from various epidemics, mainly in african countries, with the exception of the reston virus that originated in the philippines. Probing into the factors that led to the widespread outbreak, setting forth plans to counter evd cases in developing countries, and devising definitive measures to limit the spread of the disease are essential steps that must be.
International committee on taxonomy of viruses ictv. Zaire ebolavirus, more commonly known as ebola virus i. These viruses cause a disease characterised by systemic viral replication, immune suppression. This outbreak was marked by gastrointestinal clinical presentation, although the most common symptoms for ebola virus disease are fever with anorexia, asthenia, and maculopapular rash 5 to 7 days after disease onset. Rtpcr of csf and plasma were positive for ebola virus 9 months after recovering from severe primary ebola virus disease in 2015. The positive strain of the virus was the zaire strain of ebola virus. The taxonomy of the family filoviridae marburgviruses and ebolaviruses has changed several times since the discovery of its members, resulting in a plethora of species and virus names and abbreviations. Ebola virus disease evd, or simply ebola, is a viral haemorrhagic fever of humans and other primates caused by ebolaviruses. Transmission dynamics and final epidemic size of ebola virus.
This viral agent is regarded as a prototype pathogen. Since these original cases, there have been approximately 20 other outbreaks occurring through to. Burial ceremonies play a significant role in the transmission filoviruses are transmitted by direct contact with blood, bodily secretions or tissues of infected animals or humans viral titers often approach 107 pfuml the ld 50 for rodents and nonhuman primates is thought to be 110 pfu 1. The ultrastructural events involved in marburg and ebola virus morphogenesis and the associated changes in host cells have been examined in human liver tissue, in guinea pig organs, in monkey organs so far only marburg virus, and in cell cultures 3,4,6,7,8,9. Ebola virus has caused the majority of human deaths from evd, and was the cause of the. Ebolaviruses are pathogenic agents associated with a severe, potentially fatal, systemic disease in man and great apes. Mar 03, 2020 ebola virus is one of at least 30 known viruses capable of causing viral hemorrhagic fever syndrome. Ebola virus disease ebola hemorrhagic fever first appeared in 1976 with two concurrent outbreaks of acute viral hemorrhagic fever involving 284 cases 151 deaths 53% centred in nzara, sudan, and 318 cases 280 deaths 88% in yambuku near the ebola river, democratic republic of congo. Pdf the west african ebola virus disease epidemic 2014. Signs and symptoms typically start between two days and three weeks after contracting the virus with a fever, sore throat, muscular pain, and headaches. Vomiting, diarrhoea and rash usually follow, along with decreased function of the liver and kidneys. The taxonomy of ebolaviruses has been modified several times. People can get evd through direct contact with an infected animal bat or nonhuman primate or. Drc ebola outbreaks on 1 august 2018, democratic republic of congo drc declared an outbreak of ebola in the countrys northeast.
On 11 june 2019, the who confirmed that a fiveyearold boy in uganda died after being diagnosed with ebola. In mid1976 an outbreak of hemorrhagic fever was reported in southern sudan and northern zaire. Little is known about potentially modifiable factors in ebola virus disease in children. Ebola virus disease is rare and represents a miniscule fraction of the major infectious diseases burden in africa. Of interest, this is in contrast to the known diversity for ebov species, with a nucleotide difference between sequences of only 2. We undertook a retrospective cohort study of children 2015 to identify factors affecting outcome.
People can get evd through direct contact with an infected animal bat or nonhuman primate or a sick or dead person infected with ebola virus. Basically about ebola viruses the ebola viruses ebov are enveloped, non segmented, negativesense, singlestranded rna viruses, with size of genome approximately 19 kbp 2. With the number of cases passing 3,000, it is now by far the countrys largestever ebola outbreak. This list of ebola outbreaks records the known occurrences of ebola virus disease, a highly infectious and acutely lethal viral disease that has afflicted humans and animals primarily in equatorial africa. You will quickly see that ebola virus has been used in 95% or more of all the publications. Epidemiology and pathogenesis of ebola virus disease uptodate. The virus encodes for a nucleoprotein, a glycoprotein, 7 polypeptides, a.
Full genome sequencing was performed comparing the initial virus detected in the blood at presentation to the virus detected in the csf at 10 months, revealing no. An epidemic of ebola virus disease is occurring in western africa on a scale not seen. The pathogens responsible for the disease are the five ebolaviruses recognized by the international committee on taxonomy of viruses. New filovirus disease classification and nomenclature. There are currently 5 species in the ebolavirus genus. Proposal for a revised taxonomy of the family filoviridae. In the case of the ebola virus disease evd, a zoonosis caused by ebolavirus spp.