| Sudan ebolavirus | |
|---|---|
Virus classification | |
| (unranked): | Virus |
| Realm: | Riboviria |
| Kingdom: | Orthornavirae |
| Phylum: | Negarnaviricota |
| Class: | Monjiviricetes |
| Order: | Mononegavirales |
| Family: | Filoviridae |
| Genus: | Ebolavirus |
| Species: | Sudan ebolavirus |
| Member virus | |
Sudan virus (SUDV) | |
ThespeciesSudan ebolavirus is avirological taxon included in thegenusEbolavirus,familyFiloviridae,orderMononegavirales. The species has a singlevirus member,Sudan virus (SUDV).[1] The members of the species are called Sudan ebolaviruses.[1] It was discovered in 1977 and causes Ebola clinically indistinguishable from theebola Zaire strain, but is less transmissible than it. Unlike with ebola Zaire there is no vaccine available.
The nameSudan ebolavirus is derived fromSudan (the country in which Sudan virus was first discovered) and thetaxonomic suffixebolavirus (which denotes an ebolavirus species).[1]
The species was introduced in 1998 asSudan Ebola virus.[2][3] In 2002, the name was changed toSudan ebolavirus.[4][5]
A virus of the genusEbolavirus is a member of the speciesSudan ebolavirus if:[1]
Sudan virus (SUDV) is one of six known viruses within the genusEbolavirus and one of four that capable of causingEbola virus disease (EVD) inhumans and otherprimates; it is the sole member of the speciesSudan ebolavirus. SUDV is aSelect agent,World Health Organization Risk Group 4 Pathogen (requiringBiosafety Level 4-equivalent containment),National Institutes of Health/National Institute of Allergy and Infectious Diseases Category A Priority Pathogen,Centers for Disease Control and Prevention Category A Bioterrorism Agent, and listed as a Biological Agent for Export Control by theAustralia Group.[citation needed]
The first known outbreak of EVD caused bySudan ebolavirus occurred in modern-daySouth Sudan between June and November 1976, infecting 284 people and killing 151, with the first identifiable case on 27 June 1976.[6][7][8]
Sudan virus (abbreviated SUDV) was first described in 1977.[9] It is the single member of the speciesSudan ebolavirus, which is included into the genusEbolavirus, familyFiloviridae, orderMononegavirales.[1] The name Sudan virus is derived fromSouth Sudan (where it was first discovered before South Sudan seceded fromSudan[10]) and thetaxonomic suffixvirus.[citation needed]
Sudan virus was first introduced as a new "strain" of Ebola virus in 1977.[9] Sudan virus was described as "Ebola haemorrhagic fever" in a 1978 WHO report describing the 1976 Sudan outbreak.[11] In 2000, it received the designation Sudan Ebola virus[12][13] and in 2002 the name was changed to Sudan ebolavirus.[4][5] Previous abbreviations for the virus were EBOV-S (for Ebola virus Sudan) and most recently SEBOV (for Sudan Ebola virus or Sudan ebolavirus). The virus received its final designation in 2010, when it was renamed Sudan virus (SUDV).[1]
A virus of the speciesSudan ebolavirus is a Sudan virus (SUDV) if it has the properties of Sudan ebolaviruses and if itsgenome diverges from that of the prototype Sudan virus, Sudan virus variant Boniface (SUDV/Bon), by ≤10% at thenucleotide level.[1]
SUDV is one of four ebolaviruses that causesEbola virus disease (EVD) in humans (in the literature also often referred to as Ebolahemorrhagic fever, EHF). EVD due to SUDV infection cannot be differentiated from EVD caused by other ebolaviruses by clinical observation alone, which is why the clinical presentation and pathology of infections by all ebolaviruses is presented together on a separate page. The strain is less transmissible thanZaire ebolavirus.[14]
In the past, SUDV has caused the following EVD outbreaks:[15][16][additional citation(s) needed]
| Year | Geographic location | Human cases/deaths (case-fatality rate) |
| 1976 | Juba,Maridi, Nzara, and Tembura,South Sudan | 284/151 (53%) |
| 1979 | Nzara,South Sudan | 34/22 (65%) |
| 2000–2001 | Gulu,Mbarara, andMasindi Districts,Uganda | 425/224 (53%) |
| 2004 | Yambio County, South Sudan | 17/7 (41%) |
| 2011 | Luweero District,Uganda | 1/1 (100%) |
| 2014 | Equateur,Congo[17] | 0/1 * two strains reported, one Sudan and one Sudan/Zaire Hybrid to 24/08/2014 (0%) |
| 2022-2023 | Central andWestern Regions,Uganda | 164/77 (47%) |
As of 2022, there are six experimental vaccines but only three have advanced to the stage where human clinical trials have begun.[18]
As thePublic Health Agency of Canada developed a candidate RVSV vaccine for Sudan ebolavirus.Merck was developing it, but as of 18 October 2022[update] had discontinued development; Merck's monopolies on rVSV techniques, acquired with funding fromGAVI, are not available to others developing rVSV vaccines.[19]
As of 2021GeoVax was developing MVA-SUDV-VLP, which is a modified vaccinia Ankara virus producing Sudan virus-like particles; early data from their research showed the GeoVax vaccine candidate to be 100% effective at preventing death from the Sudan ebolavirus in animals.[20]
Anadenovirus based vaccine previously licensed byGSK was donated to and further developed by theSabin Vaccine Institute in partnership with theVaccine Research Center at the US National Institute of Allergy and Infectious Diseases; as of October 2022, it will be offered to contacts of known SDV cases in the2022 Uganda Ebola outbreak as part of aclinical trial.[18]
The ecology of SUDV is currently unclear and no reservoir host has yet been identified. Therefore, it remains unclear how SUDV was repeatedly introduced into human populations. As of 2009,bats have been suspected to harbor the virus because infectiousMarburg virus (MARV), a distantly related filovirus, has been isolated from bats,[21] and because traces (but no infectious particles) of the more closely relatedEbola virus (EBOV) were found in bats as well.[22]
SUDV is basically uncharacterized on a molecular level. However, its genomic sequence, and with it thegenomic organization and the conservation of individualopen reading frames, is similar to that of the other four known ebolaviruses. It is therefore currently assumed that the knowledge obtained for EBOV can beextrapolated to SUDV and that all SUDVproteins behave analogous to those of EBOV.[citation needed]
In vaccine development, access to know how is important. Knowledge and expertise including but not limited to purification techniques, cell lines, materials, software codes and their transfer of this to alternative manufacturers in the event the awardee discontinues development of a promising vaccine is critically important. The recent example of Merck abandoning the development of rVSV vaccines for Marburg (rVSV-MARV) and for Sudan-Ebola (rVSV-SUDV) is a case in point. Merck continues to retain vital know-how on the rVSV platform as it developed the rVSV vaccine for Zaire-Ebola (rVSV-ZEBOV) with funding support from GAVI. While it has transferred the rights on these vaccines back to Public Health Agency of Canada, there is no mechanism to share know how on the rVSV platform with other vaccine developers who would like to also use rVSV as a vector against other pathogens.
| Ebolavirus |
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| Marburgvirus | |||||||||||||||
| Cuevavirus |
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| Dianlovirus |
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| Striavirus |
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| Thamnovirus |
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