Hantavirus
83-747: Orthohantavirus is a genus of single-stranded, enveloped, negative-sense RNA viruses in the family Hantaviridae within the order Bunyavirales . Members of this genus may be called orthohantaviruses or simply hantaviruses . Orthohantaviruses typically cause chronic asymptomatic infection in rodents . Humans may become infected with hantaviruses through contact with rodent urine, saliva, or feces. Some strains cause potentially fatal diseases in humans, such as hantavirus hemorrhagic fever with renal syndrome (HFRS), or hantavirus pulmonary syndrome (HPS), also known as hantavirus cardiopulmonary syndrome (HCPS), while others have not been associated with known human disease (e.g. Prospect Hill virus ). HPS (HCPS)
166-454: A Neotominae-associated virus from northern South America. The evolution of shrew -borne hantaviruses appears to have involved natural occurrences of homologous recombination events and the reassortment of genome segments. The evolution of Tula orthohantavirus carried by the European common vole also appears to have involved homologous recombination events. Orthohantaviruses belong to
249-473: A cell to use this information, one strand of the DNA serves as a template for the synthesis of a complementary strand of RNA . The transcribed DNA strand is called the template strand, with antisense sequence, and the mRNA transcript produced from it is said to be sense sequence (the complement of antisense). The untranscribed DNA strand, complementary to the transcribed strand, is also said to have sense sequence; it has
332-736: A common origin for these viruses ~2000 years ago. The association with particular rodent families appears to have been more recent. The viruses carried by the subfamilies Arvicolinae and Murinae originated in Asia 500–700 years ago. These subsequently spread to Africa , Europe , North America and Siberia possibly carried by their hosts. The species infecting the subfamily Neotominae evolved 500–600 years ago in Central America and then spread toward North America. The species infecting Sigmodontinae evolved in Brazil 400 years ago. Their ancestors may have been
415-447: A double-stranded DNA molecule will be composed of two strands with sequences that are reverse complements of each other. To help molecular biologists specifically identify each strand individually, the two strands are usually differentiated as the "sense" strand and the "antisense" strand. An individual strand of DNA is referred to as positive-sense (also positive (+) or simply sense ) if its nucleotide sequence corresponds directly to
498-475: A few hours. Rodent droppings or urine of indeterminate age, though, should always be treated as infectious. As of 2021, no vaccines against hantaviruses have been approved by the U.S. FDA, but whole virus inactivated bivalent vaccines against Hantaan virus and Seoul virus are available in China and South Korea. In both countries, the use of the vaccine, combined with other preventive measures, has significantly reduced
581-425: A number of possible routes, including clathrin -dependent endocytosis , clathrin-independent receptor-mediated endocytosis, and micro pinocytosis . Viral particles are then transported to late endosomes . Gc-mediated membrane fusion with the endosomal membrane , triggered by low pH , releases the nucleocapsid into the cytoplasm . After the release of the nucleocapsids into cytoplasm, the complexes are targeted to
664-433: A panhandle structure, which likely plays a role in replication and encapsidation , facilitated by binding with the viral nucleocapsid (N) protein. The large segment is 6530–6550 nucleotides (nt) in length, the medium is 3613–3707 nt in length and the small is 1696–2083 nt in length. No nonstructural proteins are known, unlike the other genera in this family. At the 5′ and 3′ of each segment are short noncoding sequences:
747-725: A positive-sense RNA that acts as an mRNA. Some viruses (e.g. influenza viruses) have negative-sense genomes and so must carry an RNA polymerase inside the virion. Gene silencing can be achieved by introducing into cells a short "antisense oligonucleotide" that is complementary to an RNA target. This experiment was first done by Zamecnik and Stephenson in 1978 and continues to be a useful approach, both for laboratory experiments and potentially for clinical applications ( antisense therapy ). Several viruses, such as influenza viruses Respiratory syncytial virus (RSV) and SARS coronavirus (SARS-CoV), have been targeted using antisense oligonucleotides to inhibit their replication in host cells. If
830-465: A sequence that corresponds directly to the RNA codon sequence. By this logic, the RNA transcript itself is sometimes described as "sense". Some regions within a double-stranded DNA molecule code for genes , which are usually instructions specifying the order in which amino acids are assembled to make proteins, as well as regulatory sequences, splicing sites, non-coding introns , and other gene products . For
913-562: A severe consequence of infection from Andes viruses. As an emerging virus, it is more lethal than that of some of the other hantaviruses having a mortality rate between 40% and 50% in South America. By far, it has been responsible for the most recorded cases of HPS in Argentina, Chile, and Uruguay combined and contributes to a large number of kidney failure cases. Although it can be carried by both humans and rodents, Andes orthohantavirus
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#1732880619751996-398: A slightly different meaning. The genome of an RNA virus can be said to be either positive-sense , also known as a "plus-strand", or negative-sense , also known as a "minus-strand". In most cases, the terms "sense" and "strand" are used interchangeably, making terms such as "positive-strand" equivalent to "positive-sense", and "plus-strand" equivalent to "plus-sense". Whether a viral genome
1079-410: A tube into the lungs to facilitate oxygen delivery. HFRS can impair kidney function. In severe cases, patients may need dialysis to remove waste products from the blood and regulate fluid balance when the kidneys are compromised. Negative-sense In molecular biology and genetics , the sense of a nucleic acid molecule, particularly of a strand of DNA or RNA , refers to the nature of
1162-442: Is 1.18 g/cm. These features are common to all members of the family Hantaviridae . The genome of hantaviruses is negative-sense, single-stranded RNA . Their genomes are composed of three segments: the small (S), medium (M), and large (L) segments. The S segment, 1–3 kilobases (kb) in length, encodes for the nucleocapsid (N) protein. The M segment, 3.2–4.9 kb in length, encodes a glycoprotein precursor polyprotein that
1245-553: Is a "rare respiratory illness associated with the inhalation of aerosolized rodent excreta (urine and feces) contaminated by hantavirus particles". Human infections of hantaviruses have almost entirely been linked to human contact with rodent excrement; however, in 2005 and 2019, human-to-human transmission of the Andes virus was reported in South America. Orthohantaviruses are named for the Greek word ortho - meaning "straight" or "true" and for
1328-427: Is a serious lung problem that can be deadly. Hantaviruses are a global health concern, capable of causing severe illness in humans. These viruses are transmitted primarily through contact with rodents, such as rats and mice. Exposure to their urine, droppings, or saliva can increase the risk of infection. While less common, bites or scratches from infected rodents can also lead to transmission. The manner of transmission
1411-644: Is also widely used. Whether the strand is sense (positive) or antisense (negative), the default query sequence in NCBI BLAST alignment is "Plus" strand. A single-stranded genome that is used in both positive-sense and negative-sense capacities is said to be ambisense . Some viruses have ambisense genomes. Bunyaviruses have three single-stranded RNA (ssRNA) fragments, some of them containing both positive-sense and negative-sense sections; arenaviruses are also ssRNA viruses with an ambisense genome, as they have three fragments that are mainly negative-sense except for part of
1494-509: Is caused chiefly by hantaviruses in Asia and Europe. Clinical presentation varies from subclinical to fatal, depending on the virus. After an incubation period of 2–4 weeks, the typical illness starts with non-specific symptoms such as high fever, chills, headache, backache, abdominal pains, nausea, and vomiting. After the initial period, bleeding under the skin begins, often paired with low blood pressure, followed by further internal bleeding throughout
1577-476: Is characterized by fluid in the pleural cavity and the histopathology of the lungs and spleen. Lethality of ANDV in hamsters is not true of all viruses causing HCPS; hamsters infected with Sin Nombre virus , for example, show no symptoms of disease. When visiting geographical locations where Andes orthohantavirus has been documented, such as South America, people should avoid areas of high rodent populations where
1660-403: Is co-translationally cleaved into the envelope glycoproteins Gn and Gc, alternatively called G1 and G2. The L segment, 6.8–12 kb in length, encodes the L protein which functions primarily as the viral RNA-dependent RNA polymerase used for transcription and replication. Within virions , the genomic RNAs of hantaviruses are thought to complex with the N protein to form helical nucleocapsids,
1743-494: Is gaining popularity for hantavirus diagnosis. Hantavirus virions are about 80–120 nm in diameter. The lipid bilayer of the viral envelope is about 5 nm thick and is embedded with viral surface proteins to which sugar residues are attached. These glycoproteins, known as Gn and Gc, are encoded by the M segment of the viral genome. They tend to associate ( heterodimerize ) with each other and have both an interior tail and an exterior domain that extends to about 6 nm beyond
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#17328806197511826-516: Is imperative to seek healthcare immediately. Early care is more beneficial to the patient as there is no vaccine or specific treatment for HPS. In extreme cases, infected individuals may be intubated and receive oxygen therapy. Although hantavirus infections are prevalent in the United States, there currently are very few recorded cases of HPS due to infection from the Andes virus in the United States and
1909-421: Is important for labeling strands is the relative locations of the terminal 5′ phosphate group and the terminal 3′ hydroxyl group (at the ends of the strand or sequence in question), because these ends determine the direction of transcription and translation. A sequence written 5′-CGCTAT-3′ is equivalent to a sequence written 3′-TATCGC-5′ as long as the 5′ and 3′ ends are noted. If the ends are not labeled, convention
1992-401: Is important for survival. Treatment includes supportive care for breathing and prevention of shock. HCPS can be prevented by avoiding contact with rodents and their droppings. Symptoms usually start 2 to 3 weeks after a person has been exposed to the virus. Early symptoms may include: The patient can quickly become very sick. Within a few days, more serious symptoms may appear, such as: HCPS
2075-413: Is increased vascular permeability, which causes hypotension , thrombocytopenia , and leukocytosis . The pulmonary illness is the more fatal of the two, whereas the hemorrhagic fever is much more common. Treatment for both is primarily supportive as there is no specific treatment for hantavirus infections. While many hantaviruses cause either of the two diseases, some are not known to cause illness, such as
2158-616: Is most commonly found in the Oligoryzomys longicaudatus , a species of pygmy rat native to the Chile-Argentina region, and in other cases, in the Abrothrix longipilis , a long-haired grass mouse. Andes orthohantavirus is a species of Hantavirus, a group of enveloped , Negative-sense single-stranded RNA virus , belonging to the family Hantaviridae and genus orthohantavirus . All genera excluding hantavirus are air-borne viruses while
2241-455: 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,
2324-452: Is needed in order for the virus's genome to be replicated. Negative-sense (3′-to-5′) viral RNA is complementary to the viral mRNA, thus a positive-sense RNA must be produced by an RNA-dependent RNA polymerase from it prior to translation. Like DNA, negative-sense RNA has a nucleotide sequence complementary to the mRNA that it encodes; also like DNA, this RNA cannot be translated into protein directly. Instead, it must first be transcribed into
2407-470: Is no need for RNase H recognition, this can include chemistries such as 2′-O-alkyl, peptide nucleic acid (PNA), locked nucleic acid (LNA), and Morpholino oligomers. Andes orthohantavirus 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
2490-399: Is not used as the template for the mRNA; it is the DNA antisense strand that serves as the source for the protein code, because, with bases complementary to the DNA sense strand, it is used as a template for the mRNA. Since transcription results in an RNA product complementary to the DNA template strand, the mRNA is complementary to the DNA antisense strand. Hence, a base triplet 3′-TAC-5′ in
2573-399: Is of the same sense as mRNA. Some viruses (e.g. Coronaviridae ) have positive-sense genomes that can act as mRNA and be used directly to synthesize proteins without the help of a complementary RNA intermediate. Because of this, these viruses do not need to have an RNA polymerase packaged into the virion —the RNA polymerase will be one of the first proteins produced by the host cell, since it
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2656-502: Is often recommended after 72 hours of symptom onset. Early symptoms like fever, headache, muscle aches, nausea, and fatigue can be easily mistaken for influenza. A diagnosis of HPS or HFRS should be considered in individuals with a history of rodent exposure and symptoms consistent with these conditions. If you suspect hantavirus infection, seek medical attention promptly and inform your doctor of any potential rodent contact. Hantavirus diagnosis primarily depends on detecting antibodies in
2739-456: Is positive-sense or negative-sense can be used as a basis for classifying viruses. Positive-sense ( 5′ -to- 3′ ) viral RNA signifies that a particular viral RNA sequence may be directly translated into viral proteins (e.g., those needed for viral replication). Therefore, in positive-sense RNA viruses, the viral RNA genome can be considered viral mRNA, and can be immediately translated by the host cell. Unlike negative-sense RNA, positive-sense RNA
2822-454: Is related to RNA interference . Cells can produce antisense RNA molecules naturally, called microRNAs , which interact with complementary mRNA molecules and inhibit their expression . The concept has also been exploited as a molecular biology technique, by artificially introducing a transgene coding for antisense RNA in order to block the expression of a gene of interest. Radioactively or fluorescently labelled antisense RNA can be used to show
2905-484: Is that geographical clustering of hantavirus sequences may have been caused by an isolation-by-distance mechanism. Upon comparison of the hantaviruses found in hosts of orders Rodentia and Eulipotyphla , it was proposed in 2011 that the hantavirus evolutionary history is a mix of both host switching and codivergence and that ancestral shrews or moles, rather than rodents, may have been the early original hosts of ancient hantaviruses. A Bayesian analysis in 2014 suggested
2988-410: 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. Andes orthohantavirus was first identified when outbreaks of this new infection spread throughout Chile and Argentina. In 1995, it was finally characterized in Argentina on the basis of specimens from a patient who had died from HPS complications,
3071-505: Is the same for both diseases caused by hantaviruses. Among the HCPS-causing hantaviruses is the Andes orthohantavirus , which is the only hantavirus confirmed to be capable of spreading from person to person, though this is rare. Detecting hantavirus infection within the first 72 hours can be challenging. Initial tests may be negative if the virus hasn't reached detectable levels. Repeat testing
3154-450: Is to assume that both sequences are written in the 5′-to-3′ direction. The "Watson strand" refers to 5′-to-3′ top strand (5′→3′), whereas the "Crick strand" refers to the 5′-to-3′ bottom strand (3′←5′). Both Watson and Crick strands can be either sense or antisense strands depending on the specific gene product made from them. For example, the notation "YEL021W", an alias of the URA3 gene used in
3237-460: The Prospect Hill orthohantavirus . The severity of the disease varies depending on the virus causing the infection. Hantaan and Dobrava virus infections usually cause severe symptoms where 5-15% of cases are fatal. In contrast, Seoul, Saaremaa, and Puumala virus infections are usually more moderate with less than 1% dying from the disease. Complete recovery can take several weeks to months. HFRS
3320-597: The Hantan River in South Korea , where the first member species ( Hantaan virus ) was identified and isolated in 1976 by Ho Wang Lee . Overall, three syndromes are caused by hantaviruses: (1) Haemorrhagic fever with renal syndrome (HFRS), mainly in Europe and Asia; (2) Nephropathia epidemica (NE), a mild form of HFRS, caused by Puumala hantavirus, and occurring in Europe; (3) Hantavirus cardiopulmonary syndrome (HCPS), in
3403-621: The National Center for Biotechnology Information (NCBI) database, denotes that this gene is in the 21st open reading frame (ORF) from the centromere of the left arm (L) of Yeast (Y) chromosome number V (E), and that the expression coding strand is the Watson strand (W). "YKL074C" denotes the 74th ORF to the left of the centromere of chromosome XI and that the coding strand is the Crick strand (C). Another confusing term referring to "Plus" and "Minus" strand
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3486-539: The RNA-induced silencing complex (RISC). The R1 plasmid hok/sok system provides yet another example of an enzyme-dependent antisense regulation process through enzymatic degradation of the resulting RNA duplex. Other antisense mechanisms are not enzyme-dependent, but involve steric blocking of their target RNA (e.g. to prevent translation or to induce alternative splicing). Steric blocking antisense mechanisms often use oligonucleotides that are heavily modified. Since there
3569-522: The endoplasmic reticulum to the Golgi complex , where glycosylation is completed. The L protein produces nascent genomes by replication via a positive-sense RNA intermediate. Hantavirus virions are believed to assemble by association of nucleocapsids with glycoproteins embedded in the membranes of the Golgi, followed by budding into the Golgi cisternae . Nascent virions are then transported in secretory vesicles to
3652-409: The messenger RNA (mRNA) transcript, and can therefore be used to read the expected codon sequence that will ultimately be used during translation (protein synthesis) to build an amino acid sequence and then a protein. For example, the sequence "ATG" within a DNA sense strand corresponds to an "AUG" codon in the mRNA, which codes for the amino acid methionine . However, the DNA sense strand itself
3735-598: The plasma membrane and released by exocytosis . The pathogenesis of hantavirus infections is unclear as there is a lack of animal models to describe it (rats and mice do not seem to acquire severe disease). While the primary site of viral replication in the body is not known, in HFRS the main effect is in the blood vessels while in HPS most symptoms are associated with the lungs. In HFRS, there are increased vascular permeability and decreased blood pressure due to endothelial dysfunction and
3818-401: The 3′ end and UAGUAGUAUGC... at the 5′ end. The Hantavirus replication takes place strictly in the cytoplasm of a host cell primarily targeting endothelial cells. During early infection, Andes virus can produce a weak, innate immune response in the cell. The entry and uncoating of the virus begins when the virion attaches to cell receptors on the surface of the host cell, which then brings in
3901-413: The 5′ ends of the large and small segments of their genome. An RNA sequence that is complementary to an endogenous mRNA transcript is sometimes called " antisense RNA ". In other words, it is a non-coding strand complementary to the coding sequence of RNA; this is similar to negative-sense viral RNA. When mRNA forms a duplex with a complementary antisense RNA sequence, translation is blocked. This process
3984-562: The Americas. Hemorrhagic fever with renal syndrome (HFRS) is another hantavirus-related illness, primarily found in Europe and Asia. However, the Seoul virus , which causes HFRS, has a global distribution, including the United States. In the Western Hemisphere, including the United States, hantaviruses can cause hantavirus pulmonary syndrome (HPS) . The deer mouse is a common carrier of
4067-439: The Andes virus contains 1876 nucleotides in total, while encoding a 547 nucleotide-long N protein. Upon comparison of S and M segments to other variants, the Andes virus was found to form a lineage with viruses such as ESQ H-1/96, CH H-1/96 Bayou, and Black Creek Canal viruses. When expressed, the M segment generates the glycoprotein precursor (GPC) which can be cleaved into the envelope Gn and Gc proteins. The L protein encoded by
4150-469: The DNA antisense strand (complementary to the 5′-ATG-3′ of the DNA sense strand) is used as the template which results in a 5′-AUG-3′ base triplet in the mRNA. The DNA sense strand will have the triplet ATG, which looks similar to the mRNA triplet AUG but will not be used to make methionine because it will not be directly used to make mRNA. The DNA sense strand is called a "sense" strand not because it will be used to make protein (it won't be), but because it has
4233-410: The L segment possesses enzymatic functions that are involved within transcription and replication. In addition to these segments, the virion also contains RdRP which are all enclosed in an envelope. Unlike the other four genera in the family the hantavirion segments also contain a complementary 3'-terminal nucleotide sequence to the 5'-terminal sequence. These nucleotide sequences are AUCAUCAUCUG... at
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#17328806197514316-404: The RNA component of which circularizes due to sequence complementarity between the 5′ and 3′ terminal sequences of genomic segments. As with other Bunyavirales , each of the three segments has a consensus 3′-terminal nucleotide sequence (AUCAUCAUC), which is complementary to the 5′-terminal sequence and is distinct from those of the other four genera in the family. These sequences appear to form
4399-516: The RNA transcript. It is actually the antisense strand that is used as the template from which RNA polymerases construct the RNA transcript, but the complementary base-pairing by which nucleic acid polymerization occurs means that the sequence of the RNA transcript will look identical to the positive-sense strand, apart from the RNA transcript's use of uracil instead of thymine. Sometimes the phrases coding strand and template strand are encountered in place of sense and antisense, respectively, and in
4482-530: The U.S. CDC, the best prevention against contracting hantavirus is to eliminate or minimize contact with rodents in the home, workplace, or campsite. As the virus can be transmitted by rodent saliva, excretions, and bites, control of rats and mice in areas frequented by humans is key for disease prevention. General prevention can be accomplished by disposing of rodent nests, sealing any cracks and holes in homes where mice or rats could enter, setting traps, or laying down poisons or using natural predators such as cats in
4565-495: The antisense oligonucleotide contains a stretch of DNA or a DNA mimic (phosphorothioate DNA, 2′F-ANA, or others) it can recruit RNase H to degrade the target RNA. This makes the mechanism of gene silencing catalytic. Double-stranded RNA can also act as a catalytic, enzyme-dependent antisense agent through the RNAi / siRNA pathway, involving target mRNA recognition through sense-antisense strand pairing followed by target mRNA degradation by
4648-526: The blood. This is typically done using immuno-fluorescent assays (IFA) or enzyme immuno assays (EIA). During the early stages of infection, antibodies may not be specific. However, certain characteristics of IgG antibodies and the pattern of fluorescence in IFA can help distinguish new infections from past ones. In recent years, rapid point-of-care tests based on immuno-chromatographic IgM assays have become available. Additionally, RT-PCR analysis of patient blood samples
4731-461: The body. Renal dysfunction leading to further health issues begins thereafter, which may cause death. A more mild form of HFRS that occurs in Europe is called "nephropathia epidemica" (NE). Trench nephritis during World War I is now thought to have been HFRS. Hantavirus cardiopulmonary syndrome (HCPS) is a potentially fatal respiratory illness caused by a virus found in the saliva, urine, and droppings of some rodents. People can become infected with
4814-440: The context of a double-stranded DNA molecule the usage of these terms is essentially equivalent. However, the coding/sense strand need not always contain a code that is used to make a protein; both protein-coding and non-coding RNAs may be transcribed. The terms "sense" and "antisense" are relative only to the particular RNA transcript in question, and not to the DNA strand as a whole. In other words, either DNA strand can serve as
4897-432: The endoplasmic reticulum–Golgi intermediate compartments (ERGIC) through microtubular -associated movement resulting in the formation of viral factories at ERGIC. These factories then facilitate transcription and subsequent translation of the viral proteins. Transcription of viral genes must be initiated by association of the L protein with the three nucleocapsid species. In addition to transcriptase and replicase functions,
4980-399: The envelope surface. Inside the envelope are the nucleocapsids. These are composed of many copies of the nucleocapsid protein N, which interact with the three segments of the viral genome to form helical structures. The virally encoded RNA polymerase is also found in the interior. By mass, the virion is greater than 50% protein, 20–30% lipid, and 2–7% carbohydrate. The density of the virions
5063-510: The family Hantaviridae and members of both the genus and the family are called hantaviruses. The genus also belongs to the subfamily Mammantavirinae , the mammalian hantaviruses, with three other genera. Orthohantaviruses specifically are mammalian hantaviruses that are transmitted among rodents. The genus contains these 38 species: Hantaviruses that were formerly classified as species in this genus and which were not reassigned as member viruses of any existing species include: According to
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#17328806197515146-418: The flu. Signs and symptoms can appear as early as 4 days and up to 6 weeks after exposure. The only way to diagnose Andes orthohantavirus as the cause for these symptoms is by testing the patient's blood for Andes orthohantavirus genetic material or for corresponding antibodies of Andes orthohantavirus . Individuals are typically only infectious while they are showing symptoms such as having one or more of
5229-544: The following: Although there are only two possible vectors of the virus, humans and rodents, there are multiple routes of infection to be aware of. These include: Hantavirus pulmonary syndrome is an acute, severe, and sometimes fatal respiratory disease caused by an infection from the Andes orthohantavirus . Four to ten days after initial symptoms begin, respiratory symptoms indicating HPS can appear. Such symptoms include muscle aches, fatigue, shortness of breath, and fever. HPS symptoms can develop quickly, therefore, it
5312-582: The hantavirus is rodent-borne. Transmission of the hantaviruses are through aerosol exposure to rodent bodily fluids. Additionally, Hantaviruses seem to cause no detectable cytopathology in vertebrate cell cultures. The spherical virion of the Hantavirus is typically 80-120 nm long and contains the segmented single-stranded genome. The tri-segmented genome includes a S (small), M (medium), and L (large) segment that code for nucleocapsid (N), glycoproteins G1 and G2, and L protein respectively. The S segment of
5395-405: The hantavirus that leads to HPS in the U.S. In the Americas, hantaviruses can cause Hantavirus cardiopulmonary syndrome (HCPS). HCPS is a lung infection caused by viruses found in the saliva, urine, and droppings of some rodents. The illness is rare but can be deadly. Hantavirus infections in humans caused by Old World and New World hantaviruses, respectively. A common feature of the two diseases
5478-399: The home. Clean up any easy-to-get food, that might attract rodents. The duration that hantaviruses remain infectious in the environment varies based on factors such as the rodent's diet, temperature, humidity, and whether indoors or outdoors. The viruses have been demonstrated to remain active for 2–3 days at normal room temperature, while ultraviolet rays in direct sunlight kill them within
5561-798: The incidence of hantavirus infections. Apart from these vaccines, four types of vaccines have been researched: DNA vaccines targeting the M genome segment and the S genome segment, subunit vaccines that use recombinant Gn, Gc, and N proteins of the virus, virus vector vaccines that have recombinant hantavirus proteins inserted in them, and virus-like particle vaccines that contain viral proteins, but lack genetic material. Of these, only DNA vaccines have entered into clinical trials. Currently, there's no specific cure for hantavirus infection. Treatment focuses on providing supportive care, such as rest, hydration, and managing symptoms. HPS can lead to respiratory complications. Patients may require breathing assistance, including intubation. This procedure involves inserting
5644-452: The level of transcription of genes in various cell types. Some alternative antisense structural types have been experimentally applied as antisense therapy . In the United States, the Food and Drug Administration (FDA) has approved the phosphorothioate antisense oligonucleotides fomivirsen (Vitravene) and mipomersen (Kynamro) for human therapeutic use. In virology , the term "sense" has
5727-492: The long-tailed rice rat, Oligoryzomys longicaudatus , and other species of the genus Oligoryzomys , have been documented as the reservoir for ANDV. Another unique characteristic of ANDV is the availability of an animal model. ANDV causes lethal disease in the Syrian hamster ( Mesocricetus auratus ) that closely models the course of disease progression in humans, including a rapid progression from first symptoms to death, which
5810-483: The mRNA is capped by L proteins via Cap snatching . These capped RNA fragments can then be transferred to L protein, to be further trimmed in length by the endonuclease and used by the RdRp to initiate viral mRNA synthesis. Replication is terminated when the plasma membrane begins to fuse with cytoplasmic vesicles and mature virions are released. Initial signs of an Andes orthohantavirus infection can easily be mistaken for
5893-531: The most dramatic damage is seen in the kidneys, whereas in HPS, the lungs, spleen, and gall bladder are most affected. Early symptoms of HPS tend to present similarly to the flu (muscle aches, fever and fatigue) and usually appear around 2 to 3 weeks after exposure. Later stages of the disease (about 4 to 10 days after symptoms start) include difficulty breathing, shortness of breath and coughing. Findings of significant congruence between phylogenies of hantaviruses and phylogenies of their rodent reservoirs have led to
5976-616: The noncoding segment in all sequences at the 5′ end is 37–51 nt. The 3′ noncoding regions differ: L segment 38–43 nt; M segment 168–229 nt; and S segment 370–730 nt. The 3′ end of the S segment is conserved between the genera suggesting a functional role. Viral entry into host cells initiates by binding to surface cell receptors. Integrins are considered to be the main receptors for hantaviruses in vitro , but complement decay-accelerating factor (DAF) and globular heads of complement C1q receptor (gC1qR) have mediated attachment in cultured cells too. Entry may proceed through
6059-621: The rest of North America; however, there have been several cases reported in Chile and Argentina. HCPS as a result of Andes orthohantavirus infection has a case fatality rate of about 25–35% in Argentina and 37% in Chile. ANDV, lineage ANDV-Sout, is the only hantavirus for which person-to-person transmission has been described; all other human hantavirus infections are transmitted exclusively from animals to humans. Several ANDV strains are co-circulating in Argentina (e.g. Bermejo, Lechiguanas, Maciel, Oran and Pergamino). In Argentina and Chile,
6142-474: The roles of the strand and its complement in specifying a sequence of amino acids . Depending on the context, sense may have slightly different meanings. For example, the negative-sense strand of DNA is equivalent to the template strand, whereas the positive-sense strand is the non-template strand whose nucleotide sequence is equivalent to the sequence of the mRNA transcript. Because of the complementary nature of base-pairing between nucleic acid polymers,
6225-451: The same sense sequence as the mRNA transcript (though T bases in DNA are substituted with U bases in RNA). The names assigned to each strand actually depend on which direction you are writing the sequence that contains the information for proteins (the "sense" information), not on which strand is depicted as "on the top" or "on the bottom" (which is arbitrary). The only biological information that
6308-439: The same time. Furthermore, as of 2007 hantaviruses have been found in multiple species of non-rodent shrews and moles. Taking into account the inconsistencies in the theory of coevolution, it was proposed in 2009 that the patterns seen in hantaviruses in relation to their reservoirs could be attributed to preferential host switching directed by geographical proximity and adaptation to specific host types. Another proposal from 2010
6391-480: The sense or antisense strand. Most organisms with sufficiently large genomes make use of both strands, with each strand functioning as the template strand for different RNA transcripts in different places along the same DNA molecule. In some cases, RNA transcripts can be transcribed in both directions (i.e. on either strand) from a common promoter region, or be transcribed from within introns on either strand (see "ambisense" below). The DNA sense strand looks like
6474-409: The sequence of an RNA transcript which is translated or translatable into a sequence of amino acids (provided that any thymine bases in the DNA sequence are replaced with uracil bases in the RNA sequence). The other strand of the double-stranded DNA molecule is referred to as negative-sense (also negative (−) or antisense ), and is reverse complementary to both the positive-sense strand and
6557-522: The theory that rodents, although infected by the virus, are not harmed by it because of long-standing hantavirus–rodent host coevolution , although findings in 2008 led to new hypotheses regarding hantavirus evolution. Various hantaviruses have been found to infect multiple rodent species, and cases of cross-species transmission ( host switching ) have been recorded. Additionally, rates of substitution based on nucleotide sequence data reveal that hantavirus clades and rodent subfamilies may not have diverged at
6640-417: The viral L protein is also thought to have an endonuclease activity that cleaves cellular messenger RNAs (mRNAs) for the production of capped primers used to initiate transcription of viral mRNAs. As a result of this cap snatching , the mRNAs of hantaviruses are capped and contain nontemplated 5′-terminal extensions. The G1 (or Gn) and G2 (Gc) glycoproteins form hetero-oligomers and are then transported from
6723-418: The virus by breathing contaminated dust, touching an infected rodent or rodent urine or droppings, or being bitten by an infected rodent. Fever, fatigue, and muscle aches develop about 2 to 3 weeks after being exposed to the virus. A few days later, coughing and shortness of breath become severe as fluid builds up in the lungs (pulmonary edema). HCPS is diagnosed with laboratory tests. Early treatment for HCPS
6806-495: The virus is more likely to be found and transmitted quickly and easily from rodent to the next. Properly disinfecting living spaces and areas where rodents may have been present will kill the virus before it is able to be contracted. To prevent transmission from contact with infected humans, individuals, infected or not, should hand-wash frequently, abstain from kissing or sexual activity with one another, and avoid sharing spaces of close confinement for long periods of time. There
6889-538: The virus via endocytosis. By a process called pH-dependent fusion between the virion and the endosomal membrane, nucleocapsids enter the cytoplasm. The virus genome contains its own RNA-dependent RNA polymerase (RdRp) which directs both transcription and replication of the viral genome. Once the nucleocapsids are released, RdRp initiates transcription by binding to the encapsidated segments. While M segment mRNAs are translated by membrane-bound ribosomes, L and S segment mRNAs are translated by free ribosomes. Once transcribed,
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