Caliciviridae
Caliciviridae Infections
Calicivirus, Feline
Sapovirus
Vesivirus
Norovirus
Norwalk virus
Hemorrhagic Disease Virus, Rabbit
Vesicular exanthema of swine virus
Gastroenteritis
Molecular Sequence Data
Open Reading Frames
Amino Acid Sequence
Base Sequence
Encyclopedias as Topic
An outbreak of viral gastroenteritis associated with consumption of sandwiches: implications for the control of transmission by food handlers. (1/743)
Although food handlers are often implicated as the source of infection in outbreaks of food-borne viral gastroenteritis, little is known about the timing of infectivity in relation to illness. We investigated a gastroenteritis outbreak among employees of a manufacturing company and found an association (RR = 14.1, 95% CI = 2.0-97.3) between disease and eating sandwiches prepared by 6 food handlers, 1 of whom reported gastroenteritis which had subsided 4 days earlier. Norwalk-like viruses were detected by electron microscopy or reverse transcriptase-polymerase chain reaction (RT-PCR) in stool specimens from several company employees, the sick food handler whose specimen was obtained 10 days after resolution of illness, and an asymptomatic food handler. All RT-PCR product sequences were identical, suggesting a common source of infection. These data support observations from recent volunteer studies that current recommendations to exclude food handlers from work for 48-72 h after recovery from illness may not always prevent transmission of Norwalk-like viruses because virus can be shed up to 10 days after illness or while exhibiting no symptoms. (+info)A community outbreak of food-borne small round-structured virus gastroenteritis caused by a contaminated water supply. (2/743)
In August 1994, 30 of 135 (23%) bakery plant employees and over 100 people from South Wales and Bristol in the United Kingdom, were affected by an outbreak of gastroenteritis. Epidemiological studies of employees and three community clusters found illness in employees to be associated with drinking cold water at the bakery (relative risk 3.3, 95%, CI 1.6-7.0), and in community cases with eating custard slices (relative risk 19.8, 95%, CI 2.9-135.1) from a variety of stores supplied by one particular bakery. Small round-structured viruses (SRSV) were identified in stool specimens from 4 employees and 7 community cases. Analysis of the polymerase and capsid regions of the SRSV genome by reverse transcription-polymerase chain reaction (RT-PCR) demonstrated viruses of both genogroups (1 and 2) each with several different nucleotide sequences. The heterogeneity of the viruses identified in the outbreak suggests that dried custard mix may have been inadvertently reconstituted with contaminated water. The incident shows how secondary food contamination can cause wide-scale community gastroenteritis outbreaks, and demonstrates the ability of molecular techniques to support classical epidemiological methods in outbreak investigations. (+info)Immunization with potato plants expressing VP60 protein protects against rabbit hemorrhagic disease virus. (3/743)
The major structural protein VP60 of rabbit hemorrhagic disease virus (RHDV) has been produced in transgenic potato plants under the control of a cauliflower mosaic virus 35S promoter or a modified 35S promoter that included two copies of a strong transcriptional enhancer. Both types of promoters allowed the production of specific mRNAs and detectable levels of recombinant VP60, which were higher for the constructs carrying the modified 35S promoter. Rabbits immunized with leaf extracts from plants carrying this modified 35S promoter showed high anti-VP60 antibody titers and were fully protected against the hemorrhagic disease. (+info)Norwalk-like viral gastroenteritis in U.S. Army trainees--Texas, 1998. (4/743)
During August 27-September 1, 1998, 99 (12%) of 835 soldiers in one unit at a U.S. Army training center in El Paso, Texas, were hospitalized for acute gastroenteritis (AGE). Their symptoms included acute onset of vomiting, abdominal pain, diarrhea, and fever. Review of medical center admission records for AGE during the previous year indicated that fewer than five cases occurred each month. This report describes the outbreak investigation initiated on August 30 by a U.S. Army Epidemiologic Consultation Service (EPICON) team; the findings indicated the outbreak was caused by a Norwalk-like virus (NLV). (+info)Identification of a distinct common strain of "Norwalk-like viruses" having a global distribution. (5/743)
"Norwalk-like viruses" (NLVs) are the most common cause of outbreaks of nonbacterial gastroenteritis. During molecular surveillance of NLV strains from 152 outbreaks of gastroenteritis that occurred in the US between August 1993 and July 1997, we identified an NLV strain that predominated during the 1995-1996 season. The "95/96-US" strain caused 60 outbreaks in geographically distant locations within the US and was identified, by sequence comparisons, in an additional 7 countries on 5 continents during the same period. This is the first demonstration linking a single NLV strain globally and suggests that the circulation of these strains might involve patterns of transmission not previously considered. The diagnostic techniques are now available to establish a global network for surveillance of NLV strains that would highlight the importance of NLVs worldwide and allow molecular identification of common strains having a global distribution so as to consider interventions for their control. (+info)Neutralizing feature of commercially available feline calicivirus (FCV) vaccine immune sera against FCV field isolates. (6/743)
Four types of commercially available feline calicivirus (FCV) vaccine were compared in terms of their efficacy on the basis of the ability of the sera of specific-pathogen-free cats immunized by two injections of each type of vaccine to neutralize FCV field isolates. Each vaccine immune serum neutralized relatively well strains F4, F9, and 255, which were FCV laboratory strains. As to 36 strains of field isolates, however, vaccines A, B, C, and D immune sera did not neutralize 18-20 of the strains (50.0%-55.6%), 19-22 of the strains (52.8%-61.1%), 22-25 of the strains (61.1%-69.4%), and 8-16 of the strains (22.2%-44.4%), respectively. These results indicate that there is much difference in neutralizing antigenicity between the existing vaccine strains and the FCV strains that are prevalent in Japan, suggesting the need for improvement of FCV vaccines. (+info)Immunoglobulin M antibody test to detect genogroup II Norwalk-like virus infection. (7/743)
Sera obtained from adult volunteers inoculated with genogroup II Norwalk-like viruses (NLVs), Hawaii virus, and Snow Mountain virus and from patients involved in outbreaks of gastroenteritis were tested for genogroup II NLV Mexico virus-specific immunoglobulin M (IgM) by use of a monoclonal antibody, recombinant Mexico virus antigen (rMXV)-based IgM capture enzyme-linked immunosorbent assay (ELISA). Sera from genogroup I Norwalk virus (NV)-inoculated volunteers and from patients involved in a genogroup I NLV outbreak were also tested. In sera from those infected with genogroup I NV or NLVs in volunteer and outbreak studies, only 3 of 25 were rMXV IgM positive; in contrast, 24 of 25 were IgM positive for recombinant NV (rNV). In sera from those infected with genogroup II NLVs in volunteer and outbreak studies, 28 of 47 were rMXV IgM positive and none were IgM positive for rNV, showing the specificity of each IgM test for its respective genogroup. In an outbreak of gastroenteritis not characterized as being of viral etiology but suspected to be due to NV, 7 of 13 persons had IgM responses to rMXV, whereas none had IgM responses to rNV, thus establishing the diagnosis as genogroup II NLV infection. The rMXV-based IgM capture ELISA developed is specific for the diagnosis of genogroup II NLV infections. (+info)Prevalence of group A rotavirus, human calicivirus, astrovirus, and adenovirus type 40 and 41 infections among children with acute gastroenteritis in Dijon, France. (8/743)
Group A rotaviruses, human caliciviruses, astroviruses, and adenovirus types 40 and 41 were detected by enzyme immunoassay or reverse transcription-PCR in 61, 14, 6, and 3% of stool specimens from 414 children consulting for gastroenteritis between 1995 and 1998. These data highlight the importance of caliciviruses in infantile gastroenteritis. Among these, Norwalk-like viruses belonging to genogroup II were predominant. (+info)Caliciviridae is a family of single-stranded, positive-sense RNA viruses that primarily infect animals, including humans. In humans, Caliciviridae causes gastroenteritis, commonly known as stomach flu, and is responsible for a significant portion of foodborne illnesses worldwide. The name "Caliciviridae" comes from the Latin word "calyx," meaning "cup," which refers to the cup-shaped depressions on the surface of some members of this virus family.
There are five genera within Caliciviridae that infect humans: Norovirus, Sapovirus, Lagovirus, Vesivirus, and Nebovirus. Among these, Norovirus is the most common cause of acute gastroenteritis in humans, accounting for approximately 90% of all cases.
Caliciviruses are small, non-enveloped viruses that range from 27 to 40 nanometers in diameter. They have a simple structure, consisting of a single protein shell (capsid) that encloses the RNA genome. The capsid proteins of Caliciviridae are organized into two major domains: the shell domain and the protruding domain. The protruding domain contains binding sites for host cell receptors and is responsible for eliciting an immune response in the host.
Caliciviruses are highly contagious and can be transmitted through various routes, including fecal-oral transmission, ingestion of contaminated food or water, and direct contact with infected individuals or surfaces. They are resistant to many common disinfectants and can survive for extended periods on environmental surfaces, making them difficult to eliminate from healthcare settings and other high-touch areas.
In addition to their medical importance, Caliciviridae also has significance in veterinary medicine, as several members of this family infect animals such as cats, dogs, pigs, and rabbits, causing a range of clinical symptoms from gastroenteritis to respiratory illnesses.
Caliciviridae is a family of single-stranded, positive-sense RNA viruses that includes several important pathogens causing gastrointestinal illness in humans and animals. The most well-known human calicivirus is norovirus, which is the leading cause of acute viral gastroenteritis worldwide.
Calicivirus infections typically cause symptoms such as vomiting, diarrhea, abdominal cramps, nausea, and fever. The infection is usually self-limiting and lasts for a few days, but in some cases, it can lead to dehydration, especially in young children, older adults, and people with weakened immune systems.
Norovirus is highly contagious and can spread through close contact with an infected person, consumption of contaminated food or water, or touching contaminated surfaces and then touching the mouth. Prevention measures include frequent handwashing, proper food handling and preparation, and cleaning and disinfection of contaminated surfaces.
There is no specific treatment for calicivirus infections, and antibiotics are not effective against viral infections. Treatment is generally supportive and includes hydration to replace lost fluids and electrolytes. In severe cases, hospitalization may be necessary for intravenous fluid replacement and monitoring.
Feline calicivirus (FCV) is a single-stranded, positive-sense RNA virus that belongs to the family Caliciviridae. It is a common pathogen in cats and can cause a variety of clinical signs, including upper respiratory disease, oral ulcers, pneumonia, and limping syndrome. FCV is highly contagious and can be spread through direct contact with infected cats or contaminated objects.
FCV infection typically causes mild to moderate symptoms, such as sneezing, nasal discharge, conjunctivitis, and ulcers in the mouth. However, some strains of the virus can cause more severe disease, including virulent systemic disease (VSD), which is characterized by severe pneumonia, jaundice, and multi-organ failure. VSD is a rare but often fatal complication of FCV infection.
There are several vaccines available to protect cats against FCV infection. However, because there are many different strains of the virus, vaccination may not prevent infection altogether, but it can reduce the severity of clinical signs and the risk of complications. It is important to note that some vaccinated cats can still become infected with FCV and shed the virus, so it is still possible for them to transmit the virus to other cats.
In addition to vaccination, good hygiene practices, such as regular cleaning and disinfection of surfaces and cages, can help prevent the spread of FCV in multi-cat environments. It is also important to isolate sick cats from healthy ones to reduce the risk of transmission.
Sapovirus is a type of single-stranded RNA virus that belongs to the family Caliciviridae. It is a major cause of gastroenteritis (also known as stomach flu) in humans, particularly in young children and older adults. The infection typically results in vomiting and diarrhea, which can last for several days. Sapovirus is usually spread through the fecal-oral route, often through contaminated food or water. It is named after the city of Sapporo in Japan, where it was first identified in 1977.
Vesivirus is a genus of non-enveloped, single-stranded, positive-sense RNA viruses in the family Caliciviridae. These viruses are known to cause gastroenteritis in animals, particularly in primates and swine. They have been associated with mild to severe enteritis, vomiting, and diarrhea. However, they are not known to cause disease in humans. The name "vesivirus" is derived from the Latin word "vesica," meaning bladder or sac, which refers to the characteristic vesicle-like structures seen on the surface of infected cells.
Norovirus is a highly contagious virus that causes gastroenteritis, an inflammation of the stomach and intestines. It is often referred to as the "stomach flu" or "winter vomiting bug." Symptoms include nausea, vomiting, diarrhea, and abdominal pain. It can spread easily through contaminated food or water, contact with an infected person, or touching contaminated surfaces. Norovirus outbreaks are common in closed settings such as hospitals, nursing homes, schools, and cruise ships. The virus is hardy and can survive for weeks on surfaces, making it difficult to eliminate. It is also resistant to many disinfectants. There is no specific treatment for norovirus infection other than managing symptoms and staying hydrated. Vaccines are under development but not yet available.
Per the Centers for Disease Control and Prevention (CDC), Norovirus is a highly contagious virus that often causes vomiting and diarrhea. It is a common cause of gastroenteritis, which is an inflammation of the stomach and intestines. This infection is often referred to as the "stomach flu," although it is not related to the influenza virus.
Norovirus spreads easily from person to person, through contaminated food or water, or by touching contaminated surfaces. Symptoms usually develop 12 to 48 hours after exposure and include nausea, vomiting, diarrhea, stomach pain, fever, and headache.
The Norwalk virus is named after Norwalk, Ohio, where an outbreak of the illness occurred in 1968. It was first identified during an investigation into an outbreak of gastroenteritis among school children. The virus was later renamed norovirus in 2002 to reflect its broader range of hosts and clinical manifestations.
It's important to note that while Norwalk virus is a common cause of viral gastroenteritis, there are many other viruses, bacteria, and parasites that can also cause similar symptoms. If you suspect you have norovirus or any other foodborne illness, it's important to seek medical attention and avoid preparing food for others until your symptoms have resolved.
Hemorrhagic disease virus (RDV) in rabbits refers to a highly virulent calicivirus that causes a severe and often fatal disease in rabbits. The disease is characterized by acute onset of fever, loss of appetite, lethargy, and various hemorrhagic symptoms such as bleeding from the nose, mouth, and rectum. In severe cases, it can lead to internal organs' necrosis and death within 12-36 hours after the onset of clinical signs.
There are two main strains of RDV: the European brown hare syndrome virus (EBHSV) and the rabbit hemorrhagic disease virus (RHDV). Both viruses are highly contagious and can be transmitted through direct contact with infected rabbits, their feces or urine, or contaminated objects. The virus can also be spread through insects such as flies and mosquitoes.
Preventive measures include vaccination, strict biosecurity protocols, and limiting exposure to wild rabbits and insects. There is no specific treatment for RDV infection, and antibiotics are generally not effective against the virus. Supportive care, such as fluid therapy and symptomatic treatment, may be provided to help alleviate clinical signs and improve the rabbit's chances of survival.
Vesicular exanthema of swine (VES) is a viral disease that affects pigs, characterized by the formation of blisters or vesicles on the skin and mucous membranes. The causative agent of VES is a member of the Caliciviridae family, specifically the vesicular exanthema of swine virus (VESV).
The disease is highly contagious and can spread rapidly in pig populations through direct contact with infected animals or contaminated fomites. The incubation period for VES is typically 2-6 days, after which affected pigs may develop fever, lethargy, loss of appetite, and lameness. Within a few days, small fluid-filled vesicles appear on the snout, lips, ears, and coronary bands of the hooves. These vesicles can rupture, leading to the formation of raw, painful erosions that may become secondarily infected with bacteria.
While VES is not a direct threat to human health, it can cause significant economic losses in the swine industry due to decreased growth rates, reduced feed conversion, and increased mortality in affected animals. Additionally, the clinical signs of VES are similar to those of other vesicular diseases, such as foot-and-mouth disease (FMD), which can lead to costly trade restrictions and quarantines.
Historically, VES was a significant problem in the United States swine industry, but extensive vaccination programs and eradication efforts have largely eliminated the disease from domestic pig populations. However, VESV continues to circulate in wild pig populations and remains a potential threat to the swine industry.
Gastroenteritis is not a medical condition itself, but rather a symptom-based description of inflammation in the gastrointestinal tract, primarily involving the stomach and intestines. It's often referred to as "stomach flu," although it's not caused by influenza virus.
Medically, gastroenteritis is defined as an inflammation of the mucous membrane of the stomach and intestines, usually resulting in symptoms such as diarrhea, abdominal cramps, nausea, vomiting, fever, and dehydration. This condition can be caused by various factors, including viral (like rotavirus or norovirus), bacterial (such as Salmonella, Shigella, or Escherichia coli), or parasitic infections, food poisoning, allergies, or the use of certain medications.
Gastroenteritis is generally self-limiting and resolves within a few days with proper hydration and rest. However, severe cases may require medical attention to prevent complications like dehydration, which can be particularly dangerous for young children, older adults, and individuals with weakened immune systems.
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.
Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.
Phylogeny is the evolutionary history and relationship among biological entities, such as species or genes, based on their shared characteristics. In other words, it refers to the branching pattern of evolution that shows how various organisms have descended from a common ancestor over time. Phylogenetic analysis involves constructing a tree-like diagram called a phylogenetic tree, which depicts the inferred evolutionary relationships among organisms or genes based on molecular sequence data or other types of characters. This information is crucial for understanding the diversity and distribution of life on Earth, as well as for studying the emergence and spread of diseases.
A capsid is the protein shell that encloses and protects the genetic material of a virus. It is composed of multiple copies of one or more proteins that are arranged in a specific structure, which can vary in shape and symmetry depending on the type of virus. The capsid plays a crucial role in the viral life cycle, including protecting the viral genome from host cell defenses, mediating attachment to and entry into host cells, and assisting with the assembly of new virus particles during replication.
An open reading frame (ORF) is a continuous stretch of DNA or RNA sequence that has the potential to be translated into a protein. It begins with a start codon (usually "ATG" in DNA, which corresponds to "AUG" in RNA) and ends with a stop codon ("TAA", "TAG", or "TGA" in DNA; "UAA", "UAG", or "UGA" in RNA). The sequence between these two points is called a coding sequence (CDS), which, when transcribed into mRNA and translated into amino acids, forms a polypeptide chain.
In eukaryotic cells, ORFs can be located in either protein-coding genes or non-coding regions of the genome. In prokaryotic cells, multiple ORFs may be present on a single strand of DNA, often organized into operons that are transcribed together as a single mRNA molecule.
It's important to note that not all ORFs necessarily represent functional proteins; some may be pseudogenes or result from errors in genome annotation. Therefore, additional experimental evidence is typically required to confirm the expression and functionality of a given ORF.
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.
An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.
Viral proteins are the proteins that are encoded by the viral genome and are essential for the viral life cycle. These proteins can be structural or non-structural and play various roles in the virus's replication, infection, and assembly process. Structural proteins make up the physical structure of the virus, including the capsid (the protein shell that surrounds the viral genome) and any envelope proteins (that may be present on enveloped viruses). Non-structural proteins are involved in the replication of the viral genome and modulation of the host cell environment to favor viral replication. Overall, a thorough understanding of viral proteins is crucial for developing antiviral therapies and vaccines.
A base sequence in the context of molecular biology refers to the specific order of nucleotides in a DNA or RNA molecule. In DNA, these nucleotides are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) takes the place of thymine. The base sequence contains genetic information that is transcribed into RNA and ultimately translated into proteins. It is the exact order of these bases that determines the genetic code and thus the function of the DNA or RNA molecule.
A cell line is a culture of cells that are grown in a laboratory for use in research. These cells are usually taken from a single cell or group of cells, and they are able to divide and grow continuously in the lab. Cell lines can come from many different sources, including animals, plants, and humans. They are often used in scientific research to study cellular processes, disease mechanisms, and to test new drugs or treatments. Some common types of human cell lines include HeLa cells (which come from a cancer patient named Henrietta Lacks), HEK293 cells (which come from embryonic kidney cells), and HUVEC cells (which come from umbilical vein endothelial cells). It is important to note that cell lines are not the same as primary cells, which are cells that are taken directly from a living organism and have not been grown in the lab.
An encyclopedia is a comprehensive reference work containing articles on various topics, usually arranged in alphabetical order. In the context of medicine, a medical encyclopedia is a collection of articles that provide information about a wide range of medical topics, including diseases and conditions, treatments, tests, procedures, and anatomy and physiology. Medical encyclopedias may be published in print or electronic formats and are often used as a starting point for researching medical topics. They can provide reliable and accurate information on medical subjects, making them useful resources for healthcare professionals, students, and patients alike. Some well-known examples of medical encyclopedias include the Merck Manual and the Stedman's Medical Dictionary.
Organic chemistry processes refer to the chemical reactions, pathways, and mechanisms that involve organic compounds. These are primarily made up of carbon atoms bonded to hydrogen atoms, often along with other elements such as oxygen, nitrogen, sulfur, halogens, phosphorus, and silicon. Organic chemistry processes can include various types of reactions, such as substitution, addition, elimination, and rearrangement reactions, which may occur under mild conditions and can be influenced by factors like temperature, pressure, catalysts, and solvents.
These processes are essential in understanding the behavior and transformation of natural and synthetic organic compounds, including pharmaceuticals, agrochemicals, polymers, dyes, and materials with unique properties. They form the basis for various industrial applications and scientific research in fields such as medicinal chemistry, biochemistry, materials science, and environmental studies.