Caliciviridae: Difference between revisions

From WikiMD's Wellness Encyclopedia

CSV import
Tags: mobile edit mobile web edit
 
CSV import
 
(3 intermediate revisions by the same user not shown)
Line 1: Line 1:
'''Caliciviridae''' is a family of [[virus|viruses]] known for causing diseases in both humans and animals. This family includes several genera, such as ''[[Norovirus]]'', ''[[Sapovirus]]'', ''[[Lagovirus]]'', ''[[Vesivirus]]'', and ''[[Nebovirus]]'', each responsible for a range of infections. Caliciviridae viruses are small, non-enveloped, and possess a single-stranded RNA genome. They are characterized by their icosahedral capsid structure and a lack of a lipid envelope, making them resistant to many common disinfectants.
{{Short description|Family of viruses}}
{{Taxobox
| name = Caliciviridae
| virus_group = iv
| ordo = Picornavirales
| familia = Caliciviridae
}}


==Structure and Classification==
[[File:Calicivirus.jpg|thumb|right|Electron micrograph of a calicivirus]]
The Caliciviridae family is divided into several genera based on their genetic and antigenic properties. The most well-known member, ''Norovirus'', is notorious for causing outbreaks of gastroenteritis in humans, often in closed or semi-closed communities such as cruise ships, hospitals, and schools. ''Sapovirus'' also infects humans, leading to similar symptoms but is less commonly identified as the cause of outbreaks. ''Lagovirus'' and ''Vesivirus'' primarily affect animals, with ''Lagovirus'' being known for causing Rabbit Hemorrhagic Disease. ''Nebovirus'' is a more recently identified genus with a less clear impact on human or animal health.


==Transmission and Disease==
The '''Caliciviridae''' is a family of [[viruses]] that infect a wide range of hosts, including humans and animals. Members of this family are known for their small, non-enveloped, icosahedral structure and single-stranded [[RNA]] genome. The family includes several genera, with notable members such as the [[Norovirus]] and [[Sapovirus]], which are significant causes of gastroenteritis in humans.
Caliciviridae viruses are primarily transmitted through the fecal-oral route, either by direct contact with an infected individual or through contaminated food and water. They can also be spread through aerosolized particles from vomiting. These viruses are highly contagious, with ''Norovirus'' being able to infect individuals with as few as 10-100 viral particles. Diseases caused by Caliciviridae range from mild to severe gastroenteritis, characterized by symptoms such as vomiting, diarrhea, and abdominal pain. In animals, symptoms can vary significantly depending on the virus and host species but often include gastrointestinal and respiratory symptoms.
 
==Structure==
[[File:Fmicb-10-01280-g001.svg|thumb|left|Diagram of the calicivirus structure]]
Caliciviruses are characterized by their small, round, non-enveloped virions, typically 27-40 nm in diameter. The capsid is composed of 180 copies of a single protein, arranged in an icosahedral symmetry. The surface of the virion displays a distinctive cup-shaped depression, which is a hallmark of the family and gives the family its name (from Latin "calyx" meaning cup).
 
==Genome==
The genome of caliciviruses is a single-stranded, positive-sense RNA molecule, approximately 7.4 to 8.3 kilobases in length. It is organized into three open reading frames (ORFs). ORF1 encodes a polyprotein that is processed into non-structural proteins, including the RNA-dependent RNA polymerase. ORF2 encodes the major capsid protein, and ORF3 encodes a minor structural protein.
 
==Replication==
Calicivirus replication occurs in the cytoplasm of the host cell. The virus attaches to the host cell surface receptors and is internalized. The viral RNA is released into the cytoplasm, where it is translated into viral proteins. The RNA-dependent RNA polymerase synthesizes a complementary negative-sense RNA strand, which serves as a template for the production of new positive-sense RNA genomes. These genomes are packaged into new virions, which are then released from the host cell to infect new cells.
 
==Pathogenesis==
Caliciviruses are known to cause a range of diseases in humans and animals. In humans, noroviruses are the leading cause of viral gastroenteritis, characterized by acute onset of vomiting and diarrhea. Sapoviruses also cause gastroenteritis, primarily in children. In animals, caliciviruses can cause diseases such as feline calicivirus infection in cats and rabbit hemorrhagic disease in rabbits.
 
==Epidemiology==
Caliciviruses are highly contagious and can spread rapidly in closed environments such as cruise ships, nursing homes, and schools. Transmission occurs primarily through the fecal-oral route, either by direct contact with an infected person or by consuming contaminated food or water. The viruses are resistant to many common disinfectants, which contributes to their ability to cause outbreaks.


==Prevention and Control==
==Prevention and Control==
Due to their high infectivity and resistance to disinfectants, controlling Caliciviridae outbreaks can be challenging. Prevention strategies focus on maintaining strict hygiene practices, including frequent handwashing with soap and water, especially after using the bathroom and before handling food. In outbreak settings, thorough cleaning and disinfection of contaminated surfaces are crucial. For ''Norovirus'', chlorine bleach-based disinfectants are recommended due to the virus's resistance to alcohol-based sanitizers. Vaccines are currently under development for some Caliciviridae viruses, but none are available as of now.
Preventing calicivirus infections involves good hygiene practices, such as regular handwashing, especially after using the bathroom and before eating. In outbreak settings, thorough cleaning and disinfection of contaminated surfaces are crucial. Vaccines are available for some animal caliciviruses, such as the feline calicivirus, but there are currently no vaccines for human caliciviruses.
 
==Related pages==
* [[Norovirus]]
* [[Sapovirus]]
* [[Feline calicivirus]]
* [[Rabbit hemorrhagic disease virus]]


==Research and Future Directions==
[[File:Fmicb-10-01280-g002.jpg|thumb|right|Calicivirus particles under electron microscopy]]
Research on Caliciviridae is focused on understanding the molecular biology of these viruses, their pathogenesis, and immune responses in hosts. This knowledge is crucial for developing effective vaccines and antiviral therapies. Recent advances in molecular techniques, such as reverse genetics systems for ''Norovirus'', have opened new avenues for research and potential control strategies for these pathogens.


[[Category:Virology]]
[[Category:Caliciviridae]]
[[Category:Infectious diseases]]
[[Category:RNA viruses]]
{{Virus-stub}}
[[Category:Virus families]]

Latest revision as of 14:14, 21 February 2025

Family of viruses



File:Calicivirus.jpg
Electron micrograph of a calicivirus

The Caliciviridae is a family of viruses that infect a wide range of hosts, including humans and animals. Members of this family are known for their small, non-enveloped, icosahedral structure and single-stranded RNA genome. The family includes several genera, with notable members such as the Norovirus and Sapovirus, which are significant causes of gastroenteritis in humans.

Structure[edit]

Error creating thumbnail:
Diagram of the calicivirus structure

Caliciviruses are characterized by their small, round, non-enveloped virions, typically 27-40 nm in diameter. The capsid is composed of 180 copies of a single protein, arranged in an icosahedral symmetry. The surface of the virion displays a distinctive cup-shaped depression, which is a hallmark of the family and gives the family its name (from Latin "calyx" meaning cup).

Genome[edit]

The genome of caliciviruses is a single-stranded, positive-sense RNA molecule, approximately 7.4 to 8.3 kilobases in length. It is organized into three open reading frames (ORFs). ORF1 encodes a polyprotein that is processed into non-structural proteins, including the RNA-dependent RNA polymerase. ORF2 encodes the major capsid protein, and ORF3 encodes a minor structural protein.

Replication[edit]

Calicivirus replication occurs in the cytoplasm of the host cell. The virus attaches to the host cell surface receptors and is internalized. The viral RNA is released into the cytoplasm, where it is translated into viral proteins. The RNA-dependent RNA polymerase synthesizes a complementary negative-sense RNA strand, which serves as a template for the production of new positive-sense RNA genomes. These genomes are packaged into new virions, which are then released from the host cell to infect new cells.

Pathogenesis[edit]

Caliciviruses are known to cause a range of diseases in humans and animals. In humans, noroviruses are the leading cause of viral gastroenteritis, characterized by acute onset of vomiting and diarrhea. Sapoviruses also cause gastroenteritis, primarily in children. In animals, caliciviruses can cause diseases such as feline calicivirus infection in cats and rabbit hemorrhagic disease in rabbits.

Epidemiology[edit]

Caliciviruses are highly contagious and can spread rapidly in closed environments such as cruise ships, nursing homes, and schools. Transmission occurs primarily through the fecal-oral route, either by direct contact with an infected person or by consuming contaminated food or water. The viruses are resistant to many common disinfectants, which contributes to their ability to cause outbreaks.

Prevention and Control[edit]

Preventing calicivirus infections involves good hygiene practices, such as regular handwashing, especially after using the bathroom and before eating. In outbreak settings, thorough cleaning and disinfection of contaminated surfaces are crucial. Vaccines are available for some animal caliciviruses, such as the feline calicivirus, but there are currently no vaccines for human caliciviruses.

Related pages[edit]

File:Fmicb-10-01280-g002.jpg
Calicivirus particles under electron microscopy