Ebola: Difference between revisions
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==Ebola hemorrhagic fever == | ==Ebola hemorrhagic fever == | ||
===Vaccines === | ===Vaccines === | ||
Vaccines have been produced for both Ebola <ref name="Jones2005">{{cite journal |last=Jones |first=Steven |authorlink= |coauthors=''et al.'' |year=2005 |month= |title=Live attenuated recombinant vaccine protects nonhuman primates against Ebola and Marburg viruses |journal=[[Nature Medicine]] |volume=11 |issue=7 |pages=786-790 |doi=10.1038/nm1258 |url= |accessdate= |quote= }}</ref> and Marburg<ref name="Hevey1998">{{cite journal |last=Hevey |first=M |authorlink= |coauthors=''et al.'' |year=1998 |month= |title=Marburg Virus Vaccines Based upon Alphavirus Replicons Protect Guinea Pigs and Nonhuman Primates |journal=Virology |volume=251 |issue=1 |pages=28-37 |doi=10.1006/viro.1998.9367 |url= |accessdate= |quote= }}</ref> that were 99% effective in protecting a group of monkeys from the disease. These vaccines are based on either a [[recombinant]] [[Vesicular stomatitis virus]] or a recombinant [[Adenoviridae|Adenovirus]]<ref name="Sullivan2003">{{cite journal |last=Sullivan |first=Nancy |authorlink= |coauthors=''et al.'' |year=2003 |month= |title=Accelerated vaccination for Ebola virus haemorrhagic fever in non-human primates |journal=[[Nature (journal)|Nature]] |volume=424 |issue=6949 |pages=681-684 |doi=10.1038/nature01876 |url= |accessdate= |quote= }}</ref> carrying the Ebola spikeprotein on its surface. Early human vaccine efforts, like the one at [[NIAID]] in 2003, have so far not reported any successes.<ref>{{cite press release |title=NIAID Ebola Vaccine Enters Human Trial |publisher=National Institute of Allergy and Infectious Diseases |date=2003-11-18 |url=http://www3.niaid.nih.gov/news/newsreleases/2003/ebolahumantrial.htm |format= |language= |accessdate= |quote= }}</ref> The biggest problem with the vaccine is that unless the patient is given it near the onset of the virus (1-4 days after the symptoms begin) then there will be too much damage to the human body to repair, ie: ruptured arteries and capillaries, vomiting, and other symptoms which may still cause enough harm to kill or seriously traumatize the patient. | Vaccines have been produced for both Ebola <ref name="Jones2005">{{cite journal |last=Jones |first=Steven |authorlink= |coauthors=''et al.'' |year=2005 |month= |title=Live attenuated recombinant vaccine protects nonhuman primates against Ebola and Marburg viruses |journal=[[Nature Medicine]] |volume=11 |issue=7 |pages=786-790 |doi=10.1038/nm1258 |url= |accessdate= |quote= }}</ref> and Marburg<ref name="Hevey1998">{{cite journal |last=Hevey |first=M |authorlink= |coauthors=''et al.'' |year=1998 |month= |title=Marburg Virus Vaccines Based upon Alphavirus Replicons Protect Guinea Pigs and Nonhuman Primates |journal=Virology |volume=251 |issue=1 |pages=28-37 |doi=10.1006/viro.1998.9367 |url= |accessdate= |quote= }}</ref> that were 99% effective in protecting a group of monkeys from the disease. These vaccines are based on either a [[recombinant]] [[Vesicular stomatitis virus]] or a recombinant [[Adenoviridae|Adenovirus]]<ref name="Sullivan2003">{{cite journal |last=Sullivan |first=Nancy |authorlink= |coauthors=''et al.'' |year=2003 |month= |title=Accelerated vaccination for Ebola virus haemorrhagic fever in non-human primates |journal=[[Nature (journal)|Nature]] |volume=424 |issue=6949 |pages=681-684 |doi=10.1038/nature01876 |url= |accessdate= |quote= }}</ref> carrying the Ebola spikeprotein on its surface. Early human vaccine efforts, like the one at [[NIAID]] in 2003, have so far not reported any successes.<ref>{{cite press release |title=NIAID Ebola Vaccine Enters Human Trial |publisher=National Institute of Allergy and Infectious Diseases |date=2003-11-18 |url=http://www3.niaid.nih.gov/news/newsreleases/2003/ebolahumantrial.htm |format= |language= |accessdate= |quote= }}</ref> The biggest problem with the vaccine is that unless the patient is given it near the onset of the virus (1-4 days after the symptoms begin) then there will be too much damage to the human body to repair, ie: ruptured arteries and capillaries, vomiting, and other symptoms which may still cause enough harm to kill or seriously traumatize the patient. | ||
Revision as of 15:26, 5 April 2012
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| style="background:#Template:Taxobox colour;"|Ebola virus | ||||||||
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| style="background:#Template:Taxobox colour;" | Virus classification | ||||||||
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| Type species | ||||||||
| Zaïre Ebolavirus | ||||||||
| Species | ||||||||
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Reston Ebolavirus |
| Ebola | ||
| ICD-10 | A98.4 | |
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| ICD-9 | 065.8 | |
| DiseasesDB | 18043 | |
| MedlinePlus | 001339 | |
| MeSH | C02.782.417.415 | |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
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Ebola Microchapters |
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Diagnosis |
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Treatment |
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Postmortem Care |
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Case Studies |
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Ebola On the Web |
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American Roentgen Ray Society Images of Ebola |
Overview
Classification
Historical Perspective
Pathophysiology
Epidemiology & Demographics
Risk Factors
Causes
Differentiating Ebola
Natural history, Complications, and Prognosis
Diagnosis
History and Symptoms | Physical Examination | Laboratory tests | Case Studies
Treatment
Medical therapy | Primary prevention | Secondary prevention | Financial costs | Future therapies
Etymology
The virus is named after the Ebola River Valley in the Democratic Republic of the Congo (formerly Zaïre), near the site of the first recognized outbreak in 1976, in a mission run by Flemish nuns.[1]
Ebola hemorrhagic fever
Vaccines
Vaccines have been produced for both Ebola [2] and Marburg[3] that were 99% effective in protecting a group of monkeys from the disease. These vaccines are based on either a recombinant Vesicular stomatitis virus or a recombinant Adenovirus[4] carrying the Ebola spikeprotein on its surface. Early human vaccine efforts, like the one at NIAID in 2003, have so far not reported any successes.[5] The biggest problem with the vaccine is that unless the patient is given it near the onset of the virus (1-4 days after the symptoms begin) then there will be too much damage to the human body to repair, ie: ruptured arteries and capillaries, vomiting, and other symptoms which may still cause enough harm to kill or seriously traumatize the patient.
Viral reservoirs
Despite numerous studies, the wildlife reservoir of Ebolavirus has not been identified. Between 1976 and 1998, from 30,000 mammals, birds, reptiles, amphibians, and arthropods sampled from outbreak regions, no Ebolavirus was detected [6] apart from some genetic material found in six rodents (Mus setulosus and Praomys species) and a shrew (Sylvisorex ollula) collected from the Central African Republic in 1998.[7] Ebolavirus was detected in the carcasses of gorillas, chimpanzees and duikers during outbreaks in 2001 and 2003 (the carcasses were the source of the initial human infections) but the high mortality from infection in these species precludes them from acting as reservoirs.[6]
Plants, arthropods, and birds have also been considered as reservoirs, however bats are considered the most likely candidate[8]. Bats were known to reside in the cotton factory in which the index cases for the 1976 and 1979 outbreaks were employed and have also been implicated in Marburg infections in 1975 and 1980.[6] Of 24 plant species and 19 vertebrate species experimentally inoculated with Ebolavirus, only bats became infected.[9] The absence of clinical signs in these bats is characteristic of a reservoir species. In 2002-03, a survey of 1,030 animals from Gabon and the Republic of the Congo including 679 bats found Ebolavirus RNA in 13 fruit bats (Hyspignathus monstrosus, Epomops franquetti and Myonycteris torquata).[10] Bats are also known to be the reservoirs for a number of related viruses including Nipah virus, Hendra virus and lyssaviruses.
Weaponization
Because Ebola is lethal and since no approved vaccine or treatment is available, Ebola is classified as a Biosafety Level 4 agent, as well as a Category A bioterrorism agent[11] and a select agent by the CDC.
Ebola shows potential as a biological weapon because of its lethality but due to its relatively short incubation period it may be more difficult to spread since it may kill its victim before it has a chance to be transmitted, meaning that it would be hard to spread amongst small populations. However, if an outbreak occurred in a city the effects would likely be devastating.
As a terrorist weapon, Ebola has been considered by members of Japan's Aum Shinrikyo cult, whose leader, Shoko Asahara led about 40 members to Zaire in 1992 under the guise of offering medical aid to Ebola victims in what was presumably an attempt to acquire a sample of the virus.[12]
Recent outbreaks
As of August 30, 2007, 103 people (100 adults and three children) were infected by a suspected hemorrhagic fever outbreak in the village of Mweka, Democratic Republic of the Congo (DRC). The outbreak started after the funerals of two village chiefs, and 217 people in four villages fell ill. The World Health Organization sent a team to take blood samples for analysis and confirmed that many of the cases are the result of the Ebola virus [13]. The Congo's last major Ebola epidemic killed 245 people in 1995 in Kikwit, about 200 miles from the source of the Aug. 2007 outbreak.[14]
On November 30, 2007, the Uganda Ministry of Health confirmed an outbreak of Ebola in the Bundibugyo District. After confirmation of samples tested by the United States National Reference Laboratories and the Centers for Disease Control, the World Health Organization confirmed the presence of a new species of the Ebola virus.[15] The epidemic came to an official end on February 20, 2008. 149 cases of this new strain were reported and 37 of those led to deaths.
Life Cycle
- Virus attaches to host receptors through the GP (glycoprotein) surface peplomer and is endocytosed into vesicles in the host cell.
- Fusion of virus membrane with the vesicle membrane occurs; nucleocapsid is released into the cytoplasm.
- The encapsidated, negative-sense genomic ssRNA is used as a template for the synthesis ( 3' - 5') of polyadenylated, monocistronic mRNAs.
- Translation of the mRNA into viral proteins occurs using the host cell's machinery.
- Post-translational processing of viral proteins occurs. GP0 (glycoprotein precursor) is cleaved to GP1 and GP2, which are heavily glycosylated. These two molecules assemble, first into heterodimers, and then into trimers to give the surface peplomers. SGP (secreted glycoprotein) precursor is cleaved to SGP and delta peptide, both of which are released from the cell.
- As viral protein levels rise, a switch occurs from translation to replication. Using the negative-sense genomic RNA as a template, a complementary +ssRNA is synthesized; this is then used as a template for the synthesis of new genomic (-)ssRNA, which is rapidly encapsidated.
- The newly-formed nucleocapsides and envelope proteins associate at the host cell's plasma membrane; budding occurs, and the virions are released.
Cultural impact
Ebola and Marburg have served as a rich source of ideas and plotlines for many forms of entertainment. The infatuation with the virus is likely due to the high mortality rate of its victims, its mysterious nature, and its tendency to cause gruesome bleeding from bodily orifices.
In the movie Outbreak, the virus looks the same as the Ebola virus.OR In fact, the entire movie's made up virus "Motaba" is based very closely on Ebola.OR The symptoms and area of infection had relevance.
The Rage Virus from the movies 28 Days Later and 28 Weeks Later is a modified version of the Ebola virus.
In the book Outbreak, by Robin Cook, the Ebola virus is used in name as a possible weapon, with criminal intent. This book is different from the movie Outbreak of the same name
Biological warfare using airborne modifications of the Ebola virus was a main theme in Tom Clancy's novels Executive Orders and Rainbow Six.
In Resident Evil, the T-Virus is a modified version of the Progenitor Virus, created by inserting it with Ebola genes.[16]
Tomb Raider: The Cradle of Life features a biological weapon[17] consisting of a greatly accelerated form of Ebola, capable of causing death within minutes.
Much of the representation of the Ebola virus in fiction and the media is considered exaggerated or myth.[citation needed] One pervasive myth follows that the virus kills so fast that it has little time to spread. Victims die very soon after contact with the virus. In reality, the incubation time is usually about a week. The average time from onset of early symptoms to death varies in the range 3-21 days, with a mean of 10.1. Although this would prevent the transmission of the virus to many people, it is still enough time for some people to catch the disease.
Another myth states that the virus causes patients to melt, liquefy, or bleed profusely. In depictions of this type, victims of Ebola suffer from squirting blood, liquefying flesh, zombie-like faces and dramatic projectile bloody vomiting, at times, from even recently deceased. In actual fact, only a fraction of Ebola victims have severe bleeding, and most accounts of the course of the disease describe patients as dull and lethargic. Approximately 10% of patients suffer some bleeding, but this is often internal or subtle, such as bleeding from the gums. Ebola symptoms are usually limited to extreme exhaustion, vomiting, diarrhea, abdominal pain, a high fever, headaches and other body pains.
The following is an excerpt from an interview with Philippe Calain, M.D. Chief Epidemiologist, CDC Special Pathogens Branch, Kikwit 1996:
| “ | At the end of the disease the patient does not look, from the outside, as horrible as you can read in some books. They are not melting. They are not full of blood. They're in shock, muscular shock. They are not unconscious, but you would say 'obtunded', dull, quiet, very tired. Very few were hemorrhaging. Hemorrhage is not the main symptom. Less than half of the patients had some kind of hemorrhage. But the ones that had bled, died. | ” |
See also
- Dr. Ngoy Mushola
- Needle remover
- Sharps waste
- Bolivian haemorrhagic fever
- Crimean Congo hemorrhagic fever (CCHF)
- Marburg haemorrhagic fever, the first known disease caused by a filovirus
- Dr. Matthew Lukwiya (1957-Dec 5, 2000), A Ugandan doctor at the forefront of the 2000 outbreak.
- Dr. Jonah Kule, (-Dec 4, 2007)
- VHFs
- Epidemiology
- Bushmeat
References
- ↑ Bardi, Jason Socrates (2002). "Death Called a River". Scribbs Research Institute. 2 (1). Retrieved 2006-12-08.
- ↑ Jones, Steven (2005). "Live attenuated recombinant vaccine protects nonhuman primates against Ebola and Marburg viruses". Nature Medicine. 11 (7): 786–790. doi:10.1038/nm1258. Unknown parameter
|coauthors=ignored (help) - ↑ Hevey, M (1998). "Marburg Virus Vaccines Based upon Alphavirus Replicons Protect Guinea Pigs and Nonhuman Primates". Virology. 251 (1): 28–37. doi:10.1006/viro.1998.9367. Unknown parameter
|coauthors=ignored (help) - ↑ Sullivan, Nancy (2003). "Accelerated vaccination for Ebola virus haemorrhagic fever in non-human primates". Nature. 424 (6949): 681–684. doi:10.1038/nature01876. Unknown parameter
|coauthors=ignored (help) - ↑ "NIAID Ebola Vaccine Enters Human Trial" (Press release). National Institute of Allergy and Infectious Diseases. 2003-11-18.
- ↑ 6.0 6.1 6.2 Pourrut, Xavier (2005). "The natural history of Ebola virus in Africa". Microbes and Infection. 7 (7–8): 1005–1014. doi:10.1016/j.micinf.2005.04.006. Unknown parameter
|coauthors=ignored (help) - ↑ Morvan, Jaques (1999). "Identification of Ebola virus sequences present as RNA or DNA in organs of terrestrial small mammals of the Central African Republic". Microbes and Infection. 1 (14): 1193–1201. doi:10.1016/S1286-4579(99)00242-7. Unknown parameter
|coauthors=ignored (help) - ↑ "Fruit bats may carry Ebola virus". BBC News. 2005-12-11. Retrieved 2008-02-25.
- ↑ Swanepoel, R (1996). "Experimental inoculation of plants and animals with Ebola virus". Emerging Infectious Diseases. 2: 321–325. Unknown parameter
|coauthors=ignored (help) - ↑ Leroy, Eric (2005). "Fruit bats as reservoirs of Ebola virus". Nature. 438: 575–576. doi:10.1038/438575a. Unknown parameter
|coauthors=ignored (help) - ↑ Hoenen, Thomas (2006). "Ebola virus: unravelling pathogenesis to combat a deadly disease". Trends in Molecular Medicine. 12 (5): 206–215. doi:10.1016/j.molmed.2006.03.006. Unknown parameter
|coauthors=ignored (help) - ↑ Template:Cite paper
- ↑ "Ebola Outbreak Confirmed in Congo". NewScientist.com. 2007-09-11. Retrieved 2008-02-25.
- ↑ "Mystery DR Congo fever kills 100". BBC News. 2007-08-31. Retrieved 2008-02-25.
- ↑ "Uganda: Deadly Ebola Outbreak Confirmed - UN". UN News Service. 2007-11-30. Retrieved 2008-02-25.
- ↑ "Capcom.co.jp "Wesker's Report II"". Retrieved 2008-04-12.
- ↑ "Jesusfreakhideout.com "Lara Croft Tomb Raider: The Cradle of Life" Movie Review". Retrieved 2008-03-11.
External links
Overviews
- Database entry on genus Ebolavirus - ICTVdB
- Ebola Virus Haemorrhagic Fever - Proceedings of an International Colloquium on Ebola Virus Infection and Other Haemorrhagic Fevers held in Antwerp, Belgium, 6-8 December, 1977
- Questions and Answers about Ebola Hemorrhagic Fever - Center for Disease Control (CDC), retrieved 10 July 2006
- WHO Factsheet - retrieved 10 July 2006
- Vaccine Research Center (VRC) - Information concerning Ebola vaccine research studies
Outbreaks
- Ebola outbreak in Congo - CBC News, 12 September 2007. Retrieved 2007-09-13.
- Ebola 'kills over 5,000 gorillas' - BBC News, 8 December 2006. Retrieved 2006-12-08.
- History of Ebola Outbreaks - Centers for Disease Control Special Pathogens Branch, retrieved 2006-07-10.
- Infection Control for Viral Hemorrhagic Fevers in the African Health Care Setting - Center for Disease Control and Prevention, Atlanta, December 1998.
- Filovirus Global Symposium - Filomeeting 2008
Life Cycle
- Biomarker Database - information on Ebola
Infectivity
- U.S. Army Medical Research Institute of Infectious Diseases: Gene-Specific Ebola Therapies Protect Nonhuman Primates from Lethal Disease
- Lethal experimental infection of rhesus monkeys with Ebola-Zaire (Mayinga) virus by the oral and conjunctival route of exposure PubMed, February 1996, Jaax et al.
- Lethal experimental infections of rhesus monkeys by aerosolized Ebola and marburg virus PubMed, August 1995
- Marburg and Ebola viruses as aerosol threats PubMed, 2004, USAMRIID
- Other viral bioweapons: Ebola and Marburg hemorrhag fever PubMed, 2004
- Transmission of Ebola virus (Zaire strain) to uninfected control monkeys in a biocontainment laboratory PubMed, December 1993
- What is the probability of a dangerous strain of Ebola mutating and becoming airborne? Brett Russel, retrieved 2006-07-10.