Ebola virus
Encyclopedia
Ebola virus causes severe disease
in human
s and in nonhuman primates in the form of viral hemorrhagic fever
. EBOV is a Select Agent
, World Health Organization
Risk Group 4 Pathogen (requiring Biosafety 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 the Australia Group
.
Zaire ebolavirus
, which is included into the genus
Ebolavirus
, family
Filoviridae
, order
Mononegavirales
. The name Ebola virus is derived from the Ebola River
(a river that was at first thought to be in close proximity to the area in Zaire
where the first recorded Ebola virus disease outbreak occurred) and the taxonomic
suffix
virus. Ebola virus is pronounced ɛ’bɒlə vɑɪrəs (IPA) or eh-bo-luh v-eye-ruhs in English phonetic notation. According to the rules for taxon naming established by the International Committee on Taxonomy of Viruses
(ICTV), the name Ebola virus is always to be capitalized
, but is never italicized
, and may be abbreviated
(with EBOV being the official abbreviation).
in 1977 by two different research teams. At the same time, a third team introduced the name Ebola virus.. In 2000, the virus name was changed to Zaire Ebola virus, and in 2005 to Zaire ebolavirus. However, most scientific articles continued to refer to Ebola virus or used the terms Ebola virus and Zaire ebolavirus in parallel. Consequently, in 2010, the name Ebola virus was reinstated. Previous abbreviations for the virus were EBOV-Z (for Ebola virus Zaire) and most recently ZEBOV (for Zaire Ebola virus or Zaire ebolavirus). In 2010, EBOV was reinstated as the abbreviation for the virus.
is an Ebola virus if it has the properties of Zaire ebolaviruses
and if its genome
diverges from that of the prototype Zaire ebolavirus, Ebola virus variant Mayinga (EBOV/May), by ≤10% at the nucleotide
level.
of EBOV show them to have the characteristic threadlike structure of a filovirus. EBOV VP30 is around 288 amino acids long. The virions are tubular in general form but variable in overall shape and may appear as the classic shepherd's crook or eyebolt, as a U or a 6, or coiled, circular, or branched; laboratory techniques, such as centrifugation
, may be the origin of some of these formations. Virions are generally 80 nm in diameter with a lipid bilayer anchoring the glycoprotein which projects 7 to 10 nm long spikes from its surface. They are of variable length, typically around 800 nm, but may be up to 1000 nm long. In the center of the virion is a structure called nucleocapsid, which is formed by the helically wound viral genomic RNA complexed with the proteins NP, VP35, VP30, and L. It has a diameter of 80 nm and contains a central channel of 20–30 nm in diameter. Virally encoded glycoprotein
(GP) spikes 10 nm long and 10 nm apart are present on the outerviral envelope
of the virion, which is derived from the host cell membrane. Between envelope and nucleocapsid, in the so-called matrix space, the viral proteins VP40 and VP24 are located.
RNA, 18,959 to 18,961 nucleotides in length. The 3′ terminus is not polyadenylated and the 5′ end is not capped. It was found that 472 nucleotides from the 3' end and 731 nucleotides from the 5' end are sufficient for replication. It 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. The genomic material by itself is not infectious, because viral proteins, among them the RNA-dependent RNA polymerase, are necessary to transcribe the viral genome into mRNAs because it is a negative sense RNA virus, as well as for replication of the viral genome. Sections of the NP and the L genes from filoviruses have been identified as endogenous in the genomes of several groups of small mammals.
Disease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...
in human
Human
Humans are the only living species in the Homo genus...
s and in nonhuman primates in the form of viral hemorrhagic fever
Viral hemorrhagic fever
The viral hemorrhagic fevers are a diverse group of animal and human illnesses that are caused by four distinct families of RNA viruses: the families Arenaviridae, Filoviridae, Bunyaviridae, and Flaviviridae. All types of VHF are characterized by fever and bleeding disorders and all can progress...
. EBOV is a Select Agent
Select agent
In United States law, Select Agents are pathogens or biological toxins which have been declared by the U.S. Department of Health and Human Services or by the U.S. Department of Agriculture to have the "potential to pose a severe threat to public health and safety"...
, World Health Organization
World Health Organization
The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...
Risk Group 4 Pathogen (requiring Biosafety Level 4-equivalent containment), National Institutes of Health
National Institutes of Health
The National Institutes of Health are an agency of the United States Department of Health and Human Services and are the primary agency of the United States government responsible for biomedical and health-related research. Its science and engineering counterpart is the National Science Foundation...
/National Institute of Allergy and Infectious Diseases
National Institute of Allergy and Infectious Diseases
The National Institute of Allergy and Infectious Diseases is one of the 27 institutes and centers that make up the National Institutes of Health , an agency of the United States Department of Health and Human Services...
Category A Priority Pathogen, Centers for Disease Control and Prevention
Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention are a United States federal agency under the Department of Health and Human Services headquartered in Druid Hills, unincorporated DeKalb County, Georgia, in Greater Atlanta...
Category A Bioterrorism Agent
Bioterrorism
Bioterrorism is terrorism involving the intentional release or dissemination of biological agents. These agents are bacteria, viruses, or toxins, and may be in a naturally occurring or a human-modified form. For the use of this method in warfare, see biological warfare.-Definition:According to the...
, and listed as a Biological Agent for Export Control by the Australia Group
Australia Group
The Australia Group is an informal group of countries established in 1985 to help member countries to identify those of their exports which need to be controlled so as not to contribute to the spread of chemical and biological weapons .The group, initially consisting of 15 members, held its first...
.
Use of term
Ebola virus (abbreviated EBOV) was first described in 1976. Today, the virus is the single member of the speciesInternational Committee on Taxonomy of Viruses
The International Committee on Taxonomy of Viruses is a committee which authorizes and organizes the taxonomic classification of viruses. They have developed a universal taxonomic scheme for viruses and aim to describe all the viruses of living organisms. Members of the committee are considered to...
Zaire ebolavirus
Zaire ebolavirus
- Introduction and Use of Term :Zaire ebolavirus is a virological taxon included in the genus Ebolavirus, family Filoviridae, order Mononegavirales. The species has a single virus member, Ebola virus . The members of the species are called Zaire ebolaviruses...
, which is included into the genus
International Committee on Taxonomy of Viruses
The International Committee on Taxonomy of Viruses is a committee which authorizes and organizes the taxonomic classification of viruses. They have developed a universal taxonomic scheme for viruses and aim to describe all the viruses of living organisms. Members of the committee are considered to...
Ebolavirus
Ebolavirus
The genus Ebolavirus is a virological taxon included in the family Filoviridae, order Mononegavirales.This genus was introduced in 1998 as the "Ebola-like viruses". In 2002 the name was changed to Ebolavirus and in 2010 the genus was emended....
, family
International Committee on Taxonomy of Viruses
The International Committee on Taxonomy of Viruses is a committee which authorizes and organizes the taxonomic classification of viruses. They have developed a universal taxonomic scheme for viruses and aim to describe all the viruses of living organisms. Members of the committee are considered to...
Filoviridae
Filoviridae
The family Filoviridae is the taxonomic home of several related viruses that form filamentous virions. Two members of the family that are commonly known are Ebola virus and Marburg virus. Both viruses, and some of their lesser known relatives, cause severe disease in humans and nonhuman primates in...
, order
International Committee on Taxonomy of Viruses
The International Committee on Taxonomy of Viruses is a committee which authorizes and organizes the taxonomic classification of viruses. They have developed a universal taxonomic scheme for viruses and aim to describe all the viruses of living organisms. Members of the committee are considered to...
Mononegavirales
Mononegavirales
The order Mononegavirales is the taxonomic home of numerous related viruses. Members of the order that are commonly known are, for instance, Ebola virus, human respiratory syncytial virus, measles virus, mumps virus, Nipah virus, and rabies virus. All of these viruses cause significant disease in...
. The name Ebola virus is derived from the Ebola River
Ebola River
The Ebola River in northern Democratic Republic of the Congo is the headstream of the Mongala River, a tributary of the Congo River.Ebola virus and the taxonomic ranks associated with it and its relatives are named...
(a river that was at first thought to be in close proximity to the area in Zaire
Zaire
The Republic of Zaire was the name of the present Democratic Republic of the Congo between 27 October 1971 and 17 May 1997. The name of Zaire derives from the , itself an adaptation of the Kongo word nzere or nzadi, or "the river that swallows all rivers".-Self-proclaimed Father of the Nation:In...
where the first recorded Ebola virus disease outbreak occurred) and the taxonomic
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
suffix
Suffix
In linguistics, a suffix is an affix which is placed after the stem of a word. Common examples are case endings, which indicate the grammatical case of nouns or adjectives, and verb endings, which form the conjugation of verbs...
virus. Ebola virus is pronounced ɛ’bɒlə vɑɪrəs (IPA) or eh-bo-luh v-eye-ruhs in English phonetic notation. According to the rules for taxon naming established by the International Committee on Taxonomy of Viruses
International Committee on Taxonomy of Viruses
The International Committee on Taxonomy of Viruses is a committee which authorizes and organizes the taxonomic classification of viruses. They have developed a universal taxonomic scheme for viruses and aim to describe all the viruses of living organisms. Members of the committee are considered to...
(ICTV), the name Ebola virus is always to be capitalized
Capitalization
Capitalization is writing a word with its first letter as a majuscule and the remaining letters in minuscules . This of course only applies to those writing systems which have a case distinction...
, but is never italicized
Italic type
In typography, italic type is a cursive typeface based on a stylized form of calligraphic handwriting. Owing to the influence from calligraphy, such typefaces often slant slightly to the right. Different glyph shapes from roman type are also usually used—another influence from calligraphy...
, and may be abbreviated
Abbreviation
An abbreviation is a shortened form of a word or phrase. Usually, but not always, it consists of a letter or group of letters taken from the word or phrase...
(with EBOV being the official abbreviation).
Previous designations
Ebola virus was first introduced as a possible new "strain" of Marburg virusMarburg virus
Marburg virus disease is the name for the human disease caused by any of the two marburgviruses Marburg virus and Ravn virus...
in 1977 by two different research teams. At the same time, a third team introduced the name Ebola virus.. In 2000, the virus name was changed to Zaire Ebola virus, and in 2005 to Zaire ebolavirus. However, most scientific articles continued to refer to Ebola virus or used the terms Ebola virus and Zaire ebolavirus in parallel. Consequently, in 2010, the name Ebola virus was reinstated. Previous abbreviations for the virus were EBOV-Z (for Ebola virus Zaire) and most recently ZEBOV (for Zaire Ebola virus or Zaire ebolavirus). In 2010, EBOV was reinstated as the abbreviation for the virus.
Virus inclusion criteria
A virus of the species Zaire ebolavirusZaire ebolavirus
- Introduction and Use of Term :Zaire ebolavirus is a virological taxon included in the genus Ebolavirus, family Filoviridae, order Mononegavirales. The species has a single virus member, Ebola virus . The members of the species are called Zaire ebolaviruses...
is an Ebola virus if it has the properties of Zaire ebolaviruses
Zaire ebolavirus
- Introduction and Use of Term :Zaire ebolavirus is a virological taxon included in the genus Ebolavirus, family Filoviridae, order Mononegavirales. The species has a single virus member, Ebola virus . The members of the species are called Zaire ebolaviruses...
and if its genome
Genome
In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....
diverges from that of the prototype Zaire ebolavirus, Ebola virus variant Mayinga (EBOV/May), by ≤10% at the nucleotide
Nucleotide
Nucleotides are molecules that, when joined together, make up the structural units of RNA and DNA. In addition, nucleotides participate in cellular signaling , and are incorporated into important cofactors of enzymatic reactions...
level.
Disease
EBOV is one of four ebolaviruses that causes Ebola virus disease (EVD) in humans (in the literature also often referred to as Ebola hemorrhagic fever, EHF). In the past, EBOV has caused the following EVD outbreaks:| Year | Geographic location | Human cases/deaths (case-fatality rate) |
| 1976 | Yambuku Yambuku Yambuku is a small village in Mongala District in northern Democratic Republic of the Congo and was the site of the first known outbreak of the Ebola Zaire strain of the Ebola hemorrhagic fever virus... , Zaire Zaire The Republic of Zaire was the name of the present Democratic Republic of the Congo between 27 October 1971 and 17 May 1997. The name of Zaire derives from the , itself an adaptation of the Kongo word nzere or nzadi, or "the river that swallows all rivers".-Self-proclaimed Father of the Nation:In... |
318/280 (88%) |
| 1977 | Bonduni, Zaire Zaire The Republic of Zaire was the name of the present Democratic Republic of the Congo between 27 October 1971 and 17 May 1997. The name of Zaire derives from the , itself an adaptation of the Kongo word nzere or nzadi, or "the river that swallows all rivers".-Self-proclaimed Father of the Nation:In... |
1/1 (100%) |
| 1988 | Porton Down Porton Down Porton Down is a United Kingdom government and military science park. It is situated slightly northeast of Porton near Salisbury in Wiltshire, England. To the northwest lies the MoD Boscombe Down test range facility which is operated by QinetiQ... , United Kingdom United Kingdom The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages... |
1/0 (0%) [laboratory accident] |
| 1994-1995 | Woleu-Ntem and Ogooué-Ivindo Provinces, Gabon Gabon Gabon , officially the Gabonese Republic is a state in west central Africa sharing borders with Equatorial Guinea to the northwest, Cameroon to the north, and with the Republic of the Congo curving around the east and south. The Gulf of Guinea, an arm of the Atlantic Ocean is to the west... |
52/32 (62%) |
| 1995 | Kikwit Kikwit Kikwit is the largest city of Kwilu District, lying on the Kwilu River in the southwestern part of the Democratic Republic of Congo. Kikwit is also known in the region under the nickname "The Mother". The population is approximately 294,210... , Zaire Zaire The Republic of Zaire was the name of the present Democratic Republic of the Congo between 27 October 1971 and 17 May 1997. The name of Zaire derives from the , itself an adaptation of the Kongo word nzere or nzadi, or "the river that swallows all rivers".-Self-proclaimed Father of the Nation:In... |
317/245 (77%) |
| 1996 | Mayibout 2, Gabon Gabon Gabon , officially the Gabonese Republic is a state in west central Africa sharing borders with Equatorial Guinea to the northwest, Cameroon to the north, and with the Republic of the Congo curving around the east and south. The Gulf of Guinea, an arm of the Atlantic Ocean is to the west... |
31/21 (68%) |
| 1996 | Sergiyev Posad Sergiyev Posad Sergiyev Posad is a city and the administrative center of Sergiyevo-Posadsky District of Moscow Oblast, Russia. It grew in the 15th century around one of the greatest of Russian monasteries, the Trinity Lavra established by St. Sergius of Radonezh. The town status was granted to it in 1742... , Russia Russia Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects... |
1/1 (100%) [laboratory accident] |
| 1996-1997 | Ogooué-Ivindo Province, Gabon Gabon Gabon , officially the Gabonese Republic is a state in west central Africa sharing borders with Equatorial Guinea to the northwest, Cameroon to the north, and with the Republic of the Congo curving around the east and south. The Gulf of Guinea, an arm of the Atlantic Ocean is to the west... ; Cuvette-Ouest Department, Republic of the Congo Republic of the Congo The Republic of the Congo , sometimes known locally as Congo-Brazzaville, is a state in Central Africa. It is bordered by Gabon, Cameroon, the Central African Republic, the Democratic Republic of the Congo , the Angolan exclave province of Cabinda, and the Gulf of Guinea.The region was dominated by... |
62/46 (74%) |
| 2001-2002 | Ogooué-Ivindo Province, Gabon Gabon Gabon , officially the Gabonese Republic is a state in west central Africa sharing borders with Equatorial Guinea to the northwest, Cameroon to the north, and with the Republic of the Congo curving around the east and south. The Gulf of Guinea, an arm of the Atlantic Ocean is to the west... ; Cuvette-Ouest Department, Republic of the Congo Republic of the Congo The Republic of the Congo , sometimes known locally as Congo-Brazzaville, is a state in Central Africa. It is bordered by Gabon, Cameroon, the Central African Republic, the Democratic Republic of the Congo , the Angolan exclave province of Cabinda, and the Gulf of Guinea.The region was dominated by... |
124/97 (78%) |
| 2002 | Ogooué-Ivindo Province, Gabon Gabon Gabon , officially the Gabonese Republic is a state in west central Africa sharing borders with Equatorial Guinea to the northwest, Cameroon to the north, and with the Republic of the Congo curving around the east and south. The Gulf of Guinea, an arm of the Atlantic Ocean is to the west... ; Cuvette-Ouest Department, Republic of the Congo Republic of the Congo The Republic of the Congo , sometimes known locally as Congo-Brazzaville, is a state in Central Africa. It is bordered by Gabon, Cameroon, the Central African Republic, the Democratic Republic of the Congo , the Angolan exclave province of Cabinda, and the Gulf of Guinea.The region was dominated by... |
11/10 (91%) |
| 2002-2003 | Cuvette-Ouest Department, Republic of the Congo Republic of the Congo The Republic of the Congo , sometimes known locally as Congo-Brazzaville, is a state in Central Africa. It is bordered by Gabon, Cameroon, the Central African Republic, the Democratic Republic of the Congo , the Angolan exclave province of Cabinda, and the Gulf of Guinea.The region was dominated by... ; Ogooué-Ivindo Province, Gabon Gabon Gabon , officially the Gabonese Republic is a state in west central Africa sharing borders with Equatorial Guinea to the northwest, Cameroon to the north, and with the Republic of the Congo curving around the east and south. The Gulf of Guinea, an arm of the Atlantic Ocean is to the west... |
143/128 (90%) |
| 2003-2004 | Cuvette-Ouest Department, Republic of the Congo Republic of the Congo The Republic of the Congo , sometimes known locally as Congo-Brazzaville, is a state in Central Africa. It is bordered by Gabon, Cameroon, the Central African Republic, the Democratic Republic of the Congo , the Angolan exclave province of Cabinda, and the Gulf of Guinea.The region was dominated by... |
35/29 (83%) |
| 2004 | Koltsovo Koltsovo, Novosibirsk Oblast Koltsovo is an urban locality in Novosibirsky District of Novosibirsk Oblast, Russia, located from Novosibirsk. Population: Municipally, Koltsovo is incorporated as Koltsovo Urban Okrug... , Russia Russia Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects... |
1/1 (100%) [laboratory accident] |
| 2005 | Cuvette-Ouest Department, Republic of the Congo Republic of the Congo The Republic of the Congo , sometimes known locally as Congo-Brazzaville, is a state in Central Africa. It is bordered by Gabon, Cameroon, the Central African Republic, the Democratic Republic of the Congo , the Angolan exclave province of Cabinda, and the Gulf of Guinea.The region was dominated by... |
11/9 (82%) |
| 2007 | Kasai Occidental Province, Democratic Republic of the Congo Democratic Republic of the Congo The Democratic Republic of the Congo is a state located in Central Africa. It is the second largest country in Africa by area and the eleventh largest in the world... |
264/186 (71%) |
| 2008-2009 | Kasai Occidental Province, Democratic Republic of the Congo Democratic Republic of the Congo The Democratic Republic of the Congo is a state located in Central Africa. It is the second largest country in Africa by area and the eleventh largest in the world... |
32/15 (47%) |
Structure
Electron micrographsElectron microscope
An electron microscope is a type of microscope that uses a beam of electrons to illuminate the specimen and produce a magnified image. Electron microscopes have a greater resolving power than a light-powered optical microscope, because electrons have wavelengths about 100,000 times shorter than...
of EBOV show them to have the characteristic threadlike structure of a filovirus. EBOV VP30 is around 288 amino acids long. The virions are tubular in general form but variable in overall shape and may appear as the classic shepherd's crook or eyebolt, as a U or a 6, or coiled, circular, or branched; laboratory techniques, such as centrifugation
Centrifugation
Centrifugation is a process that involves the use of the centrifugal force for the sedimentation of mixtures with a centrifuge, used in industry and in laboratory settings. More-dense components of the mixture migrate away from the axis of the centrifuge, while less-dense components of the mixture...
, may be the origin of some of these formations. Virions are generally 80 nm in diameter with a lipid bilayer anchoring the glycoprotein which projects 7 to 10 nm long spikes from its surface. They are of variable length, typically around 800 nm, but may be up to 1000 nm long. In the center of the virion is a structure called nucleocapsid, which is formed by the helically wound viral genomic RNA complexed with the proteins NP, VP35, VP30, and L. It has a diameter of 80 nm and contains a central channel of 20–30 nm in diameter. Virally encoded glycoprotein
Glycoprotein
Glycoproteins are proteins that contain oligosaccharide chains covalently attached to polypeptide side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. In proteins that have segments extending...
(GP) spikes 10 nm long and 10 nm apart are present on the outerviral envelope
Viral envelope
Many viruses have viral envelopes covering their protein capsids. The envelopes typically are derived from portions of the host cell membranes , but include some viral glycoproteins. Functionally, viral envelopes are used to help viruses enter host cells...
of the virion, which is derived from the host cell membrane. Between envelope and nucleocapsid, in the so-called matrix space, the viral proteins VP40 and VP24 are located.
Genome
Each virion contains one molecule of linear, single-stranded, negative-senseSense (molecular biology)
In molecular biology and genetics, sense is a concept used to compare the polarity of nucleic acid molecules, such as DNA or RNA, to other nucleic acid molecules...
RNA, 18,959 to 18,961 nucleotides in length. The 3′ terminus is not polyadenylated and the 5′ end is not capped. It was found that 472 nucleotides from the 3' end and 731 nucleotides from the 5' end are sufficient for replication. It 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. The genomic material by itself is not infectious, because viral proteins, among them the RNA-dependent RNA polymerase, are necessary to transcribe the viral genome into mRNAs because it is a negative sense RNA virus, as well as for replication of the viral genome. Sections of the NP and the L genes from filoviruses have been identified as endogenous in the genomes of several groups of small mammals.
Replication
Being acellular, viruses do not grow through cell division; instead, they use the machinery and metabolism of a host cell to produce multiple copies of themselves, and they assemble in the cell.- The virus attaches to host receptors through the glycoprotein (GP) surface peplomerPeplomerA peplomer is a glycoprotein spike on a viral capsid or viral envelope. These protrusions will only bind to certain receptors on the host cell: they are essential for both host specificity and viral infectivity...
and is endocytosedEndocytosisEndocytosis is a process by which cells absorb molecules by engulfing them. It is used by all cells of the body because most substances important to them are large polar molecules that cannot pass through the hydrophobic plasma or cell membrane...
into vesicles in the host cell - Viral membrane fuses with vesicleVesicle (biology)A vesicle is a bubble of liquid within another liquid, a supramolecular assembly made up of many different molecules. More technically, a vesicle is a small membrane-enclosed sack that can store or transport substances. Vesicles can form naturally because of the properties of lipid membranes , or...
membrane, nucleocapsid is released into the cytoplasmCytoplasmThe cytoplasm is a small gel-like substance residing between the cell membrane holding all the cell's internal sub-structures , except for the nucleus. All the contents of the cells of prokaryote organisms are contained within the cytoplasm... - Encapsidated, negative-sense genomic ssRNA is used as a template for the synthesis (3' – 5') of polyadenylated, monocistronic mRNAs
- Using the host cell's machinery translation of the mRNA into viral proteins occurs
- Viral proteins are processed, glycoprotein precursor (GP0) 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. Secreted glycoprotein (sGP) 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 nucleocapsids and envelope proteins associate at the host cell's plasma membrane; buddingViral sheddingViral shedding refers to the successful reproduction, expulsion, and host-cell infection caused by virus progeny. Once replication has been completed and the host cell is exhausted of all resources in making viral progeny, the viruses may begin to leave the cell by several methods.The term is used...
occurs, destroying the cell.