Orthobunyavirus
Bunyamwera virus
La Crosse virus
Simbu virus
Bunyaviridae
Nucleocapsid Proteins
Nucleotide sequences and phylogeny of the nucleocapsid gene of Oropouche virus. (1/100)
The nucleotide sequence of the S RNA segment of the Oropouche (ORO) virus prototype strain TRVL 9760 was determined and found to be 754 nucleotides in length. In the virion-complementary orientation, the RNA contained two overlapping open reading frames of 693 and 273 nucleotides that were predicted to encode proteins of 231 and 91 amino acids, respectively. Subsequently, the nucleotide sequences of the nucleocapsid genes of 27 additional ORO virus strains, representing a 42 year interval and a wide geographical range in South America, were determined. Phylogenetic analyses revealed that all the ORO virus strains formed a monophyletic group that comprised three distinct lineages. Lineage I contained the prototype strain from Trinidad and most of the Brazilian strains, lineage II contained six Peruvian strains isolated between 1992 and 1998, and two strains from western Brazil isolated in 1991, while lineage III comprised four strains isolated in Panama during 1989. (+info)Phylogeny of the Simbu serogroup of the genus Bunyavirus. (2/100)
The Simbu serogroup of the genus Bunyavirus, family Bunyaviridae contains 25 viruses. Previous serological studies provided important information regarding some but not all of the relationships among Simbu serogroup viruses. This report describes the nucleotide sequence determination of the nucleocapsid (N) gene of the small genomic segment of 14 Simbu serogroup viruses and partial nucleotide sequence determination of the G2 glycoprotein-coding region (encoded by the medium RNA segment) of 19 viruses. The overall phylogeny of the Simbu serogroup inferred from analyses of the N gene was similar to that inferred from analyses of the G2 protein-coding region. Both analyses revealed that the Simbu serogroup viruses have evolved into at least five major phylogenetic lineages. In general, these phylogenetic lineages were consistent with the previous serological data, but provided a more detailed understanding of the relatedness amongst many viruses. In comparison to previous phylogenetic studies on the California and Bunyamwera serogroups of the Bunyavirus genus, the Simbu serogroup displays much larger genetic variation in the N gene (up to 40% amino acid sequence divergence). (+info)An outbreak of Rift Valley fever in Northeastern Kenya, 1997-98. (3/100)
In December 1997, 170 hemorrhagic fever-associated deaths were reported in Garissa District, Kenya. Laboratory testing identified evidence of acute Rift Valley fever virus (RVFV). Of the 171 persons enrolled in a cross-sectional study, 31(18%) were anti-RVFV immunoglobulin (Ig) M positive. An age-adjusted IgM antibody prevalence of 14% was estimated for the district. We estimate approximately 27,500 infections occurred in Garissa District, making this the largest recorded outbreak of RVFV in East Africa. In multivariable analysis, contact with sheep body fluids and sheltering livestock in one s home were significantly associated with infection. Direct contact with animals, particularly contact with sheep body fluids, was the most important modifiable risk factor for RVFV infection. Public education during epizootics may reduce human illness and deaths associated with future outbreaks. (+info)Turlock-like bunyavirus associated with encephalomyelitis and myocarditis in an ostrich chick. (4/100)
In the fall of 1995, a 20-day-old female ostrich chick, 1 of a group of 20, was presented live with clinical signs of 2 days duration characterized by unsteady gait, circling to the left, and walking backward. Another bird with similar clinical signs had died and another had recovered. The bird was euthanized and examined at necropsy. Twenty-five milliliters of serous fluid was in the abdominal cavity and there was increased pericardial fluid. Histopathology of the brain revealed mild to moderate nonsuppurative encephalitis characterized by mild multifocal malacia, perivascular cuffing by lymphocytes, and gliosis. The heart had multifocal infiltrations of lymphocytes mixed with macrophages and a few plasma cells throughout the myocardium. Cytopathic effects were observed in primary chicken embryo liver cells following inoculation with a tissue homogenate prepared from the brain of the affected ostrich. Virus particles the size and morphology of the family Bunyaviridae were observed in cell culture lysate by negative-stain electron microscopy. Viral characterization demonstrated that the virus isolate is a previously unknown serotypic variant (subtype) of Turlock virus. Twelve of 65 sera collected over a 3-year period from ostriches aged from 1 month to 4 years were positive for neutralizing antibody to both the Turlock prototype strain and the new subtype of Turlock virus described in this report. (+info)Ngari virus is a Bunyamwera virus reassortant that can be associated with large outbreaks of hemorrhagic fever in Africa. (5/100)
Two isolates of a virus of the genus Orthobunyavirus (family Bunyaviridae) were obtained from hemorrhagic fever cases during a large disease outbreak in East Africa in 1997 and 1998. Sequence analysis of regions of the three genomic RNA segments of the virus (provisionally referred to as Garissa virus) suggested that it was a genetic reassortant virus with S and L segments derived from Bunyamwera virus but an M segment from an unidentified virus of the genus Orthobunyavirus. While high genetic diversity (52%) was revealed by analysis of virus M segment nucleotide sequences obtained from 21 members of the genus Orthobunyavirus, the Garissa and Ngari virus M segments were almost identical. Surprisingly, the Ngari virus L and S segments showed high sequence identity with those of Bunyamwera virus, showing that Garissa virus is an isolate of Ngari virus, which in turn is a Bunyamwera virus reassortant. Ngari virus should be considered when investigating hemorrhagic fever outbreaks throughout sub-Saharan Africa. (+info)Analysis of the medium (M) segment sequence of Guaroa virus and its comparison to other orthobunyaviruses. (6/100)
Guaroa virus (GROV), a segmented virus in the genus Orthobunyavirus, has been linked to the Bunyamwera serogroup (BUN) through cross-reactivity in complement fixation assays of S segment-encoded nucleocapsid protein determinants, and also to the California serogroup (CAL) through cross-reactivity in neutralization assays of M segment-encoded glycoprotein determinants. Phylogenetic analysis of the S-segment sequence supported a closer relationship to the BUN serogroup for this segment and it was hypothesized that the serological reaction may indicate genome-segment reassortment. Here, cloning and sequencing of the GROV M segment are reported. Sequence analysis indicates an organization similar to that of other orthobunyaviruses, with genes in the order GN-NSm-Gc, and mature proteins generated by protease cleavage at one, and by signalase at possibly three, sites. A potential role of motifs that are more similar to CAL than to BUN virus sequences with respect to the serological reaction is discussed. No discernable evidence for reassortment was identified. (+info)Efficient bunyavirus rescue from cloned cDNA. (7/100)
Bunyaviruses are trisegmented, negative-sense RNA viruses. Previously, we described a rescue system to recover infectious Bunyamwera virus (genus Orthobunyavirus) entirely from cloned cDNA (Bridgen, A. and Elliott, R.M. (1996) Proc. Nat. Acad. Sci. USA 93, 15400-15404) utilizing a recombinant vaccinia virus expressing bacteriophage T7 RNA polymerase to drive intracellular transcription of transfected T7 promoter-containing plasmids. Here we report efforts to improve the efficiency of the system by comparing different methods of providing T7 polymerase. We found that a BHK-derived cell line BSR-T7/5 that constitutively expresses T7 RNA polymerase supported efficient and reproducible recovery of Bunyamwera virus, routinely generating >10(7) pfu per rescue experiment. Furthermore, we show that the virus can be recovered from transfecting cells with just three plasmids that express full-length antigenome viral RNAs, greatly simplifying the procedure. We suggest that this procedure should be applicable to viruses in other genera of the family Bunyaviridae and perhaps also to arenaviruses. (+info)Competitive enzyme-linked immunosorbent assay for the detection of the antibodies specific to akabane virus. (8/100)
A competitive enzyme-linked immunosorbent assay (C-ELISA) using neutralizing monoclonal antibodies (MAbs) against Akabane virus (AKAV) was developed to detect antibodies to AKAV in cattle sera. The performance of the test using 7 different competitor MAbs was evaluated in sequential serum samples and sera from cattle infected with various bovine arboviruses. The dynamics of the antibody response expressed by percentage of inhibition (PI) in C-ELISA coincided with those of neutralizing antibody titers in sequential serum samples from 2 cattle experimentally infected with AKAV. The value of PI in C-ELISA for convalescent sera from cattle infected with arboviruses correlated with the neutralizing antibody titer to AKAV but was unaffected by the antibodies to other arboviruses. In the validation experiment of C-ELISA using 286 bovine sera previously examined for the AKAV antibody by serum neutralization (SN) test, the relative specificity of C-ELISA was more than 98%, whereas the relative sensitivities of individual MAbs ranged from 49% to 82.2%. Overall agreement between C-ELISA and the SN test varied from 72% to 90% depending on the MAb. These results suggest that the C-ELISA is acceptable as a rapid and specific method for detecting antibodies to AKAV and is a potential alternative to the SN test. (+info)Orthobunyavirus is a genus of viruses in the family Peribunyaviridae, order Bunyavirales. These are enveloped, single-stranded, negative-sense RNA viruses. The genome consists of three segments: large (L), medium (M), and small (S). The L segment encodes the RNA-dependent RNA polymerase, the M segment encodes two glycoproteins (Gn and Gc) and a nonstructural protein (NSm), and the S segment encodes the nucleocapsid protein (N) and a nonstructural protein (NSs).
Orthobunyaviruses are primarily transmitted by arthropods, such as mosquitoes, ticks, and midges, and can cause disease in humans and animals. The diseases caused by orthobunyaviruses range from mild febrile illness to severe hemorrhagic fever and encephalitis. Some of the notable orthobunyaviruses include California encephalitis virus, La Crosse encephalitis virus, Oropouche virus, and Crimean-Congo hemorrhagic fever virus.
Bunyaviridae is a family of viruses that includes several genera capable of causing human disease. These viruses are primarily transmitted to humans through the bite of infected arthropods, such as mosquitoes and ticks, or through contact with infected rodents or their excreta.
Some of the diseases caused by Bunyaviridae infections include:
1. Hantavirus Pulmonary Syndrome (HPS): This is a severe, sometimes fatal, respiratory disease caused by hantaviruses. It is transmitted to humans through contact with infected rodents or their urine and droppings.
2. Crimean-Congo Hemorrhagic Fever (CCHF): This is a serious and often fatal viral hemorrhagic fever caused by the CCHF virus. It is primarily transmitted to humans through the bite of infected ticks, but can also be spread through contact with the blood or tissue of infected animals.
3. Rift Valley Fever (RVF): This is a viral disease that primarily affects animals, but can also infect humans. It is transmitted to humans through contact with the blood or tissue of infected animals, or through the bite of infected mosquitoes.
4. La Crosse Encephalitis: This is a viral disease transmitted to humans through the bite of infected mosquitoes. It primarily affects children and can cause inflammation of the brain (encephalitis).
5. Toscana Virus Infection: This is a viral disease transmitted to humans through the bite of infected sandflies. It can cause symptoms such as fever, headache, and meningitis.
Prevention measures include avoiding contact with rodents and their excreta, using insect repellent and wearing protective clothing to prevent mosquito and tick bites, and seeking prompt medical attention if symptoms of a Bunyaviridae infection develop.
Bunyamwera virus is an enveloped, single-stranded RNA virus that belongs to the family Peribunyaviridae and genus Orthobunyavirus. It was first isolated in 1943 from mosquitoes in the Bunyamwera district of Uganda. The viral genome consists of three segments: large (L), medium (M), and small (S).
The virus is primarily transmitted to vertebrates, including humans, through the bite of infected mosquitoes. It can cause a mild febrile illness in humans, characterized by fever, headache, muscle pain, and rash. However, Bunyamwera virus infection is usually asymptomatic or causes only mild symptoms in humans.
Bunyamwera virus has a wide host range, including mammals, birds, and mosquitoes, and is found in many parts of the world, particularly in tropical and subtropical regions. It is an important pathogen in veterinary medicine, causing disease in livestock such as cattle, sheep, and goats.
Research on Bunyamwera virus has contributed significantly to our understanding of the biology and ecology of bunyaviruses, which are a major cause of human and animal diseases worldwide.
La Crosse virus (LACV) is an orthobunyavirus that belongs to the California serogroup and is the most common cause of pediatric arboviral encephalitis in the United States. It is named after La Crosse, Wisconsin, where it was first identified in 1963.
LACV is primarily transmitted through the bite of infected eastern treehole mosquitoes (Aedes triseriatus), which serve as the primary vector and amplifying host for the virus. The virus can also be found in other mosquito species, such as Aedes albopictus and Aedes japonicus.
The transmission cycle of LACV involves mosquitoes feeding on infected small mammals, particularly chipmunks and squirrels, which serve as the natural reservoirs for the virus. The virus then replicates in the salivary glands of the mosquito, making it possible to transmit the virus through their bite.
LACV infection can cause a range of symptoms, from mild flu-like illness to severe neurological complications such as encephalitis (inflammation of the brain) and meningitis (inflammation of the membranes surrounding the brain and spinal cord). Most cases occur in children under the age of 16, with peak transmission during summer months.
Preventive measures for LACV include using insect repellent, wearing protective clothing, eliminating standing water around homes to reduce mosquito breeding sites, and staying indoors during peak mosquito activity hours (dawn and dusk). There is currently no specific antiviral treatment available for LACV infection, and management typically involves supportive care to address symptoms.
Simbu virus, also known as SIMBU or SV, is an arbovirus (arthropod-borne virus) from the family *Phenuiviridae*, genus *Seadornavirus*. It is primarily maintained in a transmission cycle between mosquitoes and ruminant animals such as cattle, sheep, and goats. The virus can cause asymptomatic or mild illness in humans, with symptoms like fever, headache, muscle pain, and rash. However, severe disease or long-term complications are rare.
Simbu virus is geographically widespread across Africa, Asia, Australia, and the Pacific islands. It is transmitted to humans through the bite of infected mosquitoes, mainly from the genus *Culex*. The virus has been isolated from various mosquito species, indicating its broad host range.
Research on Simbu virus is essential for understanding its ecology, transmission dynamics, and potential impacts on human health. It also provides insights into the evolution and emergence of related viruses in the family *Phenuiviridae*.
Bunyaviridae is a family of enveloped, single-stranded RNA viruses that includes more than 350 different species. These viruses are named after the type species, Bunyamwera virus, which was first isolated in 1943 from mosquitoes in Uganda.
The genome of Bunyaviridae viruses is divided into three segments: large (L), medium (M), and small (S). The L segment encodes the RNA-dependent RNA polymerase, which is responsible for replication and transcription of the viral genome. The M segment encodes two glycoproteins that form the viral envelope and are involved in attachment and fusion to host cells. The S segment encodes the nucleocapsid protein, which packages the viral RNA, and a non-structural protein that is involved in modulation of the host immune response.
Bunyaviridae viruses are transmitted to humans and animals through arthropod vectors such as mosquitoes, ticks, and sandflies. Some members of this family can cause severe disease in humans, including Hantavirus pulmonary syndrome, Crimean-Congo hemorrhagic fever, and Rift Valley fever.
Prevention and control measures for Bunyaviridae viruses include avoiding contact with vectors, using insect repellent and wearing protective clothing, and implementing vector control programs. There are no specific antiviral treatments available for most Bunyaviridae infections, although ribavirin has been shown to be effective against some members of the family. Vaccines are available for a few Bunyaviridae viruses, such as Hantavirus and Crimean-Congo hemorrhagic fever virus, but they are not widely used due to limitations in production and distribution.
Nucleocapsid proteins are structural proteins that are associated with the viral genome in many viruses. They play a crucial role in the formation and stability of the viral particle, also known as the virion. In particular, nucleocapsid proteins bind to the viral RNA or DNA genome and help to protect it from degradation by host cell enzymes. They also participate in the assembly and disassembly of the virion during the viral replication cycle.
In some viruses, such as coronaviruses, the nucleocapsid protein is also involved in regulating the transcription and replication of the viral genome. The nucleocapsid protein of SARS-CoV-2, for example, has been shown to interact with host cell proteins that are involved in the regulation of gene expression, which may contribute to the virus's ability to manipulate the host cell environment and evade the immune response.
Overall, nucleocapsid proteins are important components of many viruses and are often targeted by antiviral therapies due to their essential role in the viral replication cycle.
A viral RNA (ribonucleic acid) is the genetic material found in certain types of viruses, as opposed to viruses that contain DNA (deoxyribonucleic acid). These viruses are known as RNA viruses. The RNA can be single-stranded or double-stranded and can exist as several different forms, such as positive-sense, negative-sense, or ambisense RNA. Upon infecting a host cell, the viral RNA uses the host's cellular machinery to translate the genetic information into proteins, leading to the production of new virus particles and the continuation of the viral life cycle. Examples of human diseases caused by RNA viruses include influenza, COVID-19 (SARS-CoV-2), hepatitis C, and polio.
A viral genome is the genetic material (DNA or RNA) that is present in a virus. It contains all the genetic information that a virus needs to replicate itself and infect its host. The size and complexity of viral genomes can vary greatly, ranging from a few thousand bases to hundreds of thousands of bases. Some viruses have linear genomes, while others have circular genomes. The genome of a virus also contains the information necessary for the virus to hijack the host cell's machinery and use it to produce new copies of the virus. Understanding the genetic makeup of viruses is important for developing vaccines and antiviral treatments.
Cricetinae is a subfamily of rodents that includes hamsters, gerbils, and relatives. These small mammals are characterized by having short limbs, compact bodies, and cheek pouches for storing food. They are native to various parts of the world, particularly in Europe, Asia, and Africa. Some species are popular pets due to their small size, easy care, and friendly nature. In a medical context, understanding the biology and behavior of Cricetinae species can be important for individuals who keep them as pets or for researchers studying their physiology.