Arenaviridae | |
---|---|
(A) Electron micrograph of Lassa virus, bar = 100nm (B) diagram and (C) genome of arenavirus | |
Virus classification | |
(unranked): | Virus |
Realm: | Riboviria |
Kingdom: | Orthornavirae |
Phylum: | Negarnaviricota |
Class: | Ellioviricetes |
Order: | Bunyavirales |
Family: | Arenaviridae |
Genera | |
An arenavirus is a bi- or trisegmented ambisense RNA virus that is a member of the family Arenaviridae. [1] [2] These viruses infect rodents and occasionally humans. A class of novel, highly divergent arenaviruses, properly known as reptarenaviruses, have also been discovered which infect snakes to produce inclusion body disease, mostly in boa constrictors. At least eight arenaviruses are known to cause human disease. The diseases derived from arenaviruses range in severity. Aseptic meningitis, a severe human disease that causes inflammation covering the brain and spinal cord, can arise from the lymphocytic choriomeningitis virus. Hemorrhagic fever syndromes, including Lassa fever, are derived from infections such as Guanarito virus, Junin virus, Lassa virus, Lujo virus, [3] Machupo virus, Sabia virus, or Whitewater Arroyo virus. [4] Because of the epidemiological association with rodents, some arenaviruses and bunyaviruses are designated as roboviruses.
Viewed in cross-section, arenaviruses contain grainy particles that are ribosomes acquired from their host cells. It is from this characteristic that they acquired the name arena , from the Latin root meaning sand . [5] The ribosomal structures are not believed to be essential for virus replication. Virus particles, or virions, are pleomorphic (variable in shape) but are often spherical, with a diameter of 60–300 nm, and are covered with surface glycoprotein spikes. [6]
The virus contains a beaded nucleocapsid with two single-stranded RNA segments. The nucleocapsid consists of a core of nucleic acid enclosed in a protein coat. Although they are categorized as negative-sense viruses, [7] arenaviruses are ambisense. While sections of their genome encode genes in the negative sense (reverse polarity), other sections encode genes in the opposite (forward/positive sense) direction. This complex gene expression structure is theorized to be a primitive regulatory system, allowing the virus to control what proteins are synthesized at what point in the life cycle. The life cycle of the arenavirus is restricted to the cell cytoplasm.[ citation needed ]
Arenaviruses have a segmented RNA genome that consists of two single-stranded ambisense RNAs. [8] As with all negative-sense RNA viruses, the genomic RNA alone is not infectious and the viral replication machinery is required to initiate infection within a host cell. [9] Genomic sense RNA packaged into the arenavirus virion is designated negative-sense RNA, and must first be copied into a positive-sense mRNA in order to produce viral protein. [10] The RNA segments are denoted Small (S), Medium (M; if present), and Large (L), [8] [11] and code for four viral proteins in a unique ambisense coding strategy. [12] [13] For mammarenaviruses and reptarenaviruses, each RNA segment codes for two viral proteins in opposite orientation such that the negative-sense RNA genome serves as the template for transcription of a single mRNA and the positive-sense copy of the RNA genome templates a second mRNA. [10] The separate coding sequences of the two viral proteins are divided by an intergenic region RNA sequence that is predicted to fold into a stable hairpin structure. [14]
The extreme termini of each RNA segment contains a 19 nucleotide highly conserved sequence that is critical for recruitment of the viral replication machinery and initiation of viral mRNA transcription and genomic replication. [15] [16] [17] [18] [19] The conserved 5' and 3' RNA termini sequences are complementary and allows each RNA segment to adopt a double-stranded RNA panhandle structure [20] that maintains the termini in close proximity and results in a circular appearance to purified arenavirus genomic templates visualized by electron microscopy. [21] [22] The double-stranded RNA panhandle structure is critical for efficient viral RNA synthesis, [18] [23] but potential interterminal double-stranded RNA interactions must be transiently relieved in order to recruit the viral polymerase. [19]
The S-segment RNA is approximately 3.5 kb, and encodes the viral nucleocapsid protein (NP) and glycoprotein (GPC). [24] The L-segment RNA is approximately 7.2 kb, and encodes the viral RNA-dependent RNA-polymerase (L) and a small RING-domain containing protein (Z). [25] [26] [27]
The Z protein forms homo oligomers and a structural component of the virions. [28] The formation of these oligomers is an essential step for particle assembly and budding. Binding between Z and the viral envelope glycoprotein complex is required for virion infectivity. Z also interacts with the L and NP proteins. Polymerase activity appears to be modulated by the association between the L and Z proteins. Interaction between the Z and NP proteins is critical for genome packaging.[ citation needed ]
The glycoprotein (GP) is synthesised as a precursor molecule. [29] It is cleaved into three parts - GP1, GP2 and a stable signal peptide (SSP). These reactions are catalysed by cellular signal peptidases and the cellular enzyme Subtilisin Kexin Isozyme-1 (SKI-1)/Site-1 Protease (S1P). These processes are essential for fusion competence and incorporation of mature GP into nascent budding virion particles.[ citation needed ]
Within the family Arenaviridae, arenaviruses were formerly all placed in the genus Arenavirus, but in 2015 were divided into the genera Mammarenavirus for those with mammalian hosts and Reptarenavirus for those infecting snakes. [30] [31] Reptarenaviruses and mammarenavirus are separated by an impenetrable species barrier. Infected rodents cannot pass disease onto snakes, and IBD in captive snakes is not transmissible to humans.[ citation needed ]
A third genus, Hartmanivirus (not to be confused with genus Haartmanvirus of vibrio phages in family Demerecviridae , order Caudovirales ), has also been established, [32] including other species that infect snakes. The organisation of the genome of this genus is typical of arenaviruses but their glycoproteins resemble those of filoviruses. Species in this genus lack the matrix protein. [33]
A fourth genus, Antennavirus , has also been established [34] to accommodate two arenaviruses found in striated frogfish ( Antennarius striatus ). [35] A third antennavirus has been detected in Chinook salmon and sockeye salmon. [36]
Mammarenaviruses can be divided into two serogroups, which differ genetically and by geographical distribution: [37] When the virus is classified "Old World" this means it was found in the Eastern Hemisphere in places such as Europe, Asia, and Africa. When it is found in the Western Hemisphere, in places such as Argentina, Bolivia, Venezuela, Brazil, and the United States, it is classified "New World". Lymphocytic choriomeningitis (LCM) virus is the only mammarenavirus found worldwide because of its ubiquitous Old World host, the house mouse. Old and New World area viruses appear to have diverged ~45,000 years ago. [38] The Old World Mammarenaviruses originated ~23.1-1.88 thousand years ago, most likely in Southern Africa, while the New World Mammarenaviruses evolved in the Latin America-Caribbean region ~41.4-3.3 thousand years ago. [38]
The evolution of the Mammarenavirus genus has been studied. [38] The New World and Old World species diverged less than 45,000 years ago. The New World species evolved between 41,400 and 3,300 years ago in the Latin America-Caribbean region. The Old World species evolved between 23,100 and 1,880 years ago, most likely in southern Africa. [38]
Some arenaviruses are zoonotic pathogens and are generally associated with rodent—transmitted disease in humans. Each virus usually is associated with a particular rodent host species in which it is maintained. Arenaviruses persist in nature by infecting rodents first and then transmitted into humans. Humans can be infected through mucosal exposure to aerosols, or by direct contact of abraded skin with the infectious material, derived from infected rodents. [6] Aerosols are fine mists or sprays of rodent dried excreta, especially urine that is dropped in the environment. Most of the Arenaviruses caught by humans are within their own homes when these rodents seek shelter. The virus can be caught in factories, from food that has been contaminated, or within agricultural work areas. Humans' risk of contracting the Arenavirus infection is related to age, race, or sex within the degree of contact with the dried rodent excreta.[ citation needed ]
Virus | Disease | Host | Distribution |
---|---|---|---|
Dandenong [39] | Dandenong hemorrhagic fever | Unknown | old world ( Australian cases from Serbia ) |
Lymphocytic choriomeningitis virus | Lymphocytic choriomeningitis | House mouse (Mus musculus) | Worldwide |
Lassa virus | Lassa fever | Natal Multimammate Mouse (Mastomys natalensis) | West Africa |
Junin virus | Argentine hemorrhagic fever | Drylands Vesper Mouse (Calomys musculinus) | Argentina |
Machupo virus | Bolivian hemorrhagic fever | Large Vesper Mouse (Calomys callosus) | Bolivia |
Guanarito virus | Venezuelan hemorrhagic fever | Short-tailed Cane Mouse (Zygodontomys brevicauda) | Venezuela |
Sabiá virus | Brazilian hemorrhagic fever | Unknown | Brazil |
Tacaribe virus | Bat ( Artibeus ) | Trinidad | |
Flexal virus | Influenza-like illness | Rice rat ( Oryzomys ) | Brazil |
Whitewater Arroyo virus | Hemorrhagic fever | Woodrat ( Neotoma ) | Southwestern United States |
All of these diseases pose a great threat to public health in the regions where it is taking place. For example, when the Old World Lassa virus turns into Lassa fever, this usually results in a significant amount of mortality. Similarly the New World Junin virus causes Argentine hemorrhagic fever. This fever is a severe illness with hemorrhagic and neurological manifestations and a case fatality of fifteen to thirty percent. [6] The way this virus spreads is through increased traveling to and from endemic regions. This traveling has led to the importation of Lassa fever into non-endemic metropolitan areas all over the world.
A new species of arenavirus named the Lujo virus has been linked to five patients who exhibited symptoms of viral hemorrhagic fever in South Africa. [40] The disease originated near Lusaka, Zambia and spread to Johannesburg, South Africa, after the first patient was transported to a hospital there. The results of genetic sequencing tests conducted by epidemiologists at Columbia University in New York City, USA, and at the Special Pathogens Branch of the Centers for Disease Control in Atlanta, USA, provided evidence that the causative agent of the disease is a virus from the family Arenaviridae, which ultimately resulted in the deaths of four out of the five infected in Zambia and South Africa during the outbreak which began in September 2008.[ citation needed ]
Arenavirus has also pinpointed as the cause of death of three donor organ recipients in Australia who contracted the virus after receiving kidney and a liver donations from a single infected organ donor in late 2006. All three died in the first week of 2007. [41] [42]
WHO and its Global Outbreak Alert and Response Network (GOARN) partners continue to support the Ministries of Health of the two countries in various facets of the outbreak investigation, including laboratory diagnosis, investigations, active case finding and follow-up of contacts. [43]
Very few treatment methods are available. The current lack of a licensed vaccine and limited therapeutic options for the arenavirus make it arguably among the most neglected virus groups. The only licensed drug for the treatment of human arenavirus infection is the nucleoside analogue ribavirin. [44] Ribavirin reduces morbidity and mortality in humans infected with certain arenaviruses, such as LASV and JUNV infections, if it is taken in the early stages of the disease. Ribavirin displays mixed success in treating severe arenaviral disease and is associated with significant toxicities. [45]
Effective antiviral drugs need to be produced at a low cost, taken orally, and able to withstand tropical climates due to the regions where these infections are occurring. For this reason high throughput screening (HTS) of small molecular libraries could be the answer to finding a better remedy. HTS collects libraries of small synthetic molecules that can be used to identify protein promoting "agonist" molecules or protein inhibiting "antagonist" interactions. [44] With HTS sustainable antiviral drugs can be discovered against possible new human pathogenic viruses.
Immunotherapy is another potential approach. Monoclonal antibodies against Junin virus have been tested in animal models. An immunotherapeutic agent active against all tested mammarenaviruses that use the transferrin receptor 1 as their receptor was under investigation in 2020. [46]
Flavivirus, renamed Orthoflavivirus in 2023, is a genus of positive-strand RNA viruses in the family Flaviviridae. The genus includes the West Nile virus, dengue virus, tick-borne encephalitis virus, yellow fever virus, Zika virus and several other viruses which may cause encephalitis, as well as insect-specific flaviviruses (ISFs) such as cell fusing agent virus (CFAV), Palm Creek virus (PCV), and Parramatta River virus (PaRV). While dual-host flaviviruses can infect vertebrates as well as arthropods, insect-specific flaviviruses are restricted to their competent arthropods. The means by which flaviviruses establish persistent infection in their competent vectors and cause disease in humans depends upon several virus-host interactions, including the intricate interplay between flavivirus-encoded immune antagonists and the host antiviral innate immune effector molecules.
Mouse mammary tumor virus (MMTV) is a milk-transmitted retrovirus like the HTL viruses, HI viruses, and BLV. It belongs to the genus Betaretrovirus. MMTV was formerly known as Bittner virus, and previously the "milk factor", referring to the extra-chromosomal vertical transmission of murine breast cancer by adoptive nursing, demonstrated in 1936, by John Joseph Bittner while working at the Jackson Laboratory in Bar Harbor, Maine. Bittner established the theory that a cancerous agent, or "milk factor", could be transmitted by cancerous mothers to young mice from a virus in their mother's milk. The majority of mammary tumors in mice are caused by mouse mammary tumor virus.
Bunyavirales is an order of segmented negative-strand RNA viruses with mainly tripartite genomes. Member viruses infect arthropods, plants, protozoans, and vertebrates. It is the only order in the class Ellioviricetes. The name Bunyavirales derives from Bunyamwera, where the original type species Bunyamwera orthobunyavirus was first discovered. Ellioviricetes is named in honor of late virologist Richard M. Elliott for his early work on bunyaviruses.
Lassa mammarenavirus (LASV) is an arenavirus that causes Lassa hemorrhagic fever, a type of viral hemorrhagic fever (VHF), in humans and other primates. Lassa mammarenavirus is an emerging virus and a select agent, requiring Biosafety Level 4-equivalent containment. It is endemic in West African countries, especially Sierra Leone, the Republic of Guinea, Nigeria, and Liberia, where the annual incidence of infection is between 300,000 and 500,000 cases, resulting in 5,000 deaths per year.
Viral hemorrhagic fevers (VHFs) are a diverse group of animal and human illnesses. VHFs may be caused by five distinct families of RNA viruses: the families Filoviridae, Flaviviridae, Rhabdoviridae, and several member families of the Bunyavirales order such as Arenaviridae, and Hantaviridae. All types of VHF are characterized by fever and bleeding disorders and all can progress to high fever, shock and death in many cases. Some of the VHF agents cause relatively mild illnesses, such as the Scandinavian nephropathia epidemica, while others, such as Ebola virus, can cause severe, life-threatening disease.
Lymphocytic choriomeningitis (LCM) is a rodent-borne viral infectious disease that presents as aseptic meningitis, encephalitis or meningoencephalitis. Its causative agent is lymphocytic choriomeningitis mammarenavirus (LCMV), a member of the family Arenaviridae. The name was coined by Charles Armstrong in 1934.
Venezuelan hemorrhagic fever (VHF) is a zoonotic human illness first identified in 1989. The disease is most prevalent in several rural areas of central Venezuela and is caused by Guanarito mammarenavirus (GTOV) which belongs to the Arenaviridae family. The short-tailed cane mouse is the main host for GTOV which is spread mostly by inhalation of aerosolized droplets of saliva, respiratory secretions, urine, or blood from infected rodents. Person-to-person spread is possible, but uncommon.
Pestivirus is a genus of viruses, in the family Flaviviridae. Viruses in the genus Pestivirus infect mammals, including members of the family Bovidae and the family Suidae. There are 11 species in this genus. Diseases associated with this genus include: hemorrhagic syndromes, abortion, and fatal mucosal disease.
Murine coronavirus (M-CoV) is a virus in the genus Betacoronavirus that infects mice. Belonging to the subgenus Embecovirus, murine coronavirus strains are enterotropic or polytropic. Enterotropic strains include mouse hepatitis virus (MHV) strains D, Y, RI, and DVIM, whereas polytropic strains, such as JHM and A59, primarily cause hepatitis, enteritis, and encephalitis. Murine coronavirus is an important pathogen in the laboratory mouse and the laboratory rat. It is the most studied coronavirus in animals other than humans, and has been used as an animal disease model for many virological and clinical studies.
Seoul orthohantavirus (SEOV) is a member of the genus Orthohantavirus of rodent-borne viruses, and is one of the four hantaviruses that are known to cause Hantavirus hemorrhagic fever with renal syndrome (HFRS). It is an Old World hantavirus; a negative sense, single-stranded, tri-segmented RNA virus.
Andes orthohantavirus (ANDV), a species of Orthohantavirus, is a major causative agent of hantavirus cardiopulmonary syndrome (HCPS) and hantavirus pulmonary syndrome (HPS) in South America. It is named for the Andes mountains of Chile and Argentina, where it was first discovered. Originating in the reservoir of rodents, Andes orthohantavirus is easily transmitted to humans who come into contact with infected rodents or their fecal droppings. However, infected rodents do not appear ill, so there is no readily apparent indicator to determine whether the rodent is infected or not. Additionally, Andes orthohantavirus, specifically, is the only hantavirus that can be spread by human to human contact via bodily fluids or long-term contact from one infected individual to a healthy person.
Mammarenavirus juninense, better known as the Junin virus or Junín virus (JUNV), is an arenavirus in the Mammarenavirus genus that causes Argentine hemorrhagic fever (AHF). The virus took its original name from the city of Junín, around which the first cases of infection were reported, in 1958.
Rice hoja blanca tenuivirus (RHBV), Spanish for "white leaf rice virus", is a plant virus in the family Phenuiviridae. RHBV causes Hoja blanca disease (HBD), which affects the leaves of the rice plant Oryza sativa, stunting the growth of the plant or killing it altogether. RHBV is carried by an insect vector, Tagosodes orizicolus, a type of planthopper. The virus is found in South America, Mexico, throughout Central America, the Caribbean region, and the southern United States. In South America, the disease is endemic to Colombia, Venezuela, Ecuador, Peru, Suriname, French Guiana and Guyana.
Lujo is a bisegmented RNA virus—a member of the family Arenaviridae—and a known cause of viral hemorrhagic fever (VHF) in humans. Its name was suggested by the Special Pathogens Unit of the National Institute for Communicable Diseases of the National Health Laboratory Service (NICD-NHLS) by using the first two letters of the names of the cities involved in the 2008 outbreak of the disease, Lusaka (Zambia) and Johannesburg. It is the second pathogenic Arenavirus to be described from the African continent—the first being Lassa virus—and since 2012 has been classed as a "Select Agent" under U.S. law.
Picornain 3C is a protease found in picornaviruses, which cleaves peptide bonds of non-terminal sequences. Picornain 3C’s endopeptidase activity is primarily responsible for the catalytic process of selectively cleaving Gln-Gly bonds in the polyprotein of poliovirus and with substitution of Glu for Gln, and Ser or Thr for Gly in other picornaviruses. Picornain 3C are cysteine proteases related by amino acid sequence to trypsin-like serine proteases. Picornain 3C is encoded by enteroviruses, rhinoviruses, aphtoviruses and cardioviruses. These genera of picoviruses cause a wide range of infections in humans and mammals.
Oyewale Tomori is a Nigerian professor of virology, educational administrator, and former vice chancellor of Redeemer's University. In 2024, he became the chair of West Africa National Academy of Scientists.
West Nile virus (WNV) is a single-stranded RNA virus that causes West Nile fever. It is a member of the family Flaviviridae, from the genus Flavivirus, which also contains the Zika virus, dengue virus, and yellow fever virus. The virus is primarily transmitted by mosquitoes, mostly species of Culex. The primary hosts of WNV are birds, so that the virus remains within a "bird–mosquito–bird" transmission cycle. The virus is genetically related to the Japanese encephalitis family of viruses. Humans and horses both exhibit disease symptoms from the virus, and symptoms rarely occur in other animals.
Mammarenavirus is a genus of viruses in the family Arenaviridae. The name is a portmanteau of mammal and the former name Arenavirus, and differentiates it from the reptile-associated Reptarenavirus. Arenavirus comes from the Latin arena (sand) for the sandy appearance of the virions.
Negative-strand RNA viruses are a group of related viruses that have negative-sense, single-stranded genomes made of ribonucleic acid (RNA). They have genomes that act as complementary strands from which messenger RNA (mRNA) is synthesized by the viral enzyme RNA-dependent RNA polymerase (RdRp). During replication of the viral genome, RdRp synthesizes a positive-sense antigenome that it uses as a template to create genomic negative-sense RNA. Negative-strand RNA viruses also share a number of other characteristics: most contain a viral envelope that surrounds the capsid, which encases the viral genome, −ssRNA virus genomes are usually linear, and it is common for their genome to be segmented.
Mopeia mammarenavirus (MOPV) is a species of virus in the genus Mammarenavirus. It was initially isolated from the Mastomys natalensis mouse in the East African country of Mozambique in 1977. It is of the "Old World" Arenavirus lineage and is closely related to Lassa mammarenavirus, sharing 75% of its amino acid sequence.
{{cite book}}
: |journal=
ignored (help){{cite book}}
: |journal=
ignored (help)