''Roseolovirus'' is a genus of
virus
A virus is a submicroscopic infectious agent that replicates only inside the living Cell (biology), cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are ...
es in the order ''
Herpesvirales
''Herpesvirales'' is an order of dsDNA viruses (Baltimore group I) with animal hosts, characterised by a common morphology consisting of an icosahedral capsid enclosed in a glycoprotein-containing lipid envelope. Common infections in humans cause ...
'', in the family ''
Herpesviridae
''Orthoherpesviridae'', previously named and more widely known as ''Herpesviridae'', is a large family of DNA viruses that cause infections and certain diseases in animals, including humans. The members of this family are commonly known as herp ...
'', in the subfamily ''
Betaherpesvirinae
''Betaherpesvirinae'' is a subfamily of viruses in the order '' Herpesvirales'' and in the family ''Herpesviridae''. Mammals serve as natural hosts. There are 26 species in this subfamily, divided among 5 genera. Diseases associated with this su ...
''. There are currently six species in this genus. Diseases associated with this genus include:
HHV-6: sixth disease (
roseola
Roseola, also known as sixth disease, is an infectious disease caused by certain types of human herpes viruses. Most infections occur before the age of three. Symptoms vary from absent to the classic presentation of a fever of rapid onset follo ...
infantum, exanthema subitum);
HHV-7: symptoms analog to the 'sixth disease'.
Species
The genus consists of the following six species:
* ''
Roseolovirus humanbeta7''
* ''
Roseolovirus humanbeta6a''
* ''
Roseolovirus humanbeta6b''
* ''
Roseolovirus macacinebeta9''
* ''
Roseolovirus muridbeta3''
* ''
Roseolovirus suidbeta2''
Structure
Viruses in ''Roseolovirus'' are enveloped, with icosahedral, spherical to pleomorphic, and round geometries, and T=16 symmetry. The diameter is around 150-200 nm. Genomes are linear and non-segmented, around 200kb in length.
Life cycle
Viral replication is nuclear, and is lysogenic. Entry into the host cell is achieved by attachment of the viral
glycoprotein
Glycoproteins are proteins which contain oligosaccharide (sugar) chains covalently attached to amino acid side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known a ...
s to host receptors, which mediates
endocytosis
Endocytosis is a cellular process in which Chemical substance, substances are brought into the cell. The material to be internalized is surrounded by an area of cell membrane, which then buds off inside the cell to form a Vesicle (biology and chem ...
. Replication follows the dsDNA bidirectional replication model. DNA-templated transcription, with some alternative splicing mechanism, is the method of transcription. The virus exits the host cell by nuclear egress, and budding.
Humans serve as the natural host. Transmission routes are direct contact and respiratory.
Diseases
''Human herpesvirus 6'' (HHV-6) is a set of two closely related herpes viruses known as HHV-6A and HHV-6B that infect nearly all human beings, typically before the age of two. The acquisition of HHV-6 in infancy is often symptomatic, resulting in childhood fever, diarrhea, and exanthem subitum rash (commonly known as roseola). Although rare, this initial infection can also cause
febrile seizure
A febrile seizure, also known as a fever fit or febrile convulsion, is a seizure associated with a high body temperature but without any serious underlying health issue. They most commonly occur in children between the ages of 6 months and 5 ye ...
s, encephalitis or intractable seizures.
Like the other herpesviruses (
Epstein–Barr virus
The Epstein–Barr virus (EBV), also known as human herpesvirus 4 (HHV-4), is one of the nine known Herpesviridae#Human herpesvirus types, human herpesvirus types in the Herpesviridae, herpes family, and is one of the most common viruses in ...
, ''
Human alphaherpesvirus 3
Varicella zoster virus (VZV), also known as human herpesvirus 3 (HHV-3, HHV3), is one of nine known herpes viruses that can infect humans. It causes chickenpox (varicella) commonly affecting children and young adults, and shingles (herpes zos ...
'', etc.), HHV-6 establishes lifelong latency and can become reactivated later in life. This reactivation has been associated with many clinical manifestations. Reactivation can occur in locations throughout the body, including the brain, lungs, heart, kidney and gastrointestinal tract. In some cases, HHV-6 reactivation in the brain tissue can cause cognitive dysfunction, permanent disability and death.
A growing number of studies also suggest that HHV-6 may play a role in a subset of patients with chronic neurological conditions such as
multiple sclerosis
Multiple sclerosis (MS) is an autoimmune disease resulting in damage to myelinthe insulating covers of nerve cellsin the brain and spinal cord. As a demyelinating disease, MS disrupts the nervous system's ability to Action potential, transmit ...
, mesial
temporal lobe epilepsy
In the field of neurology, temporal lobe epilepsy is an enduring brain disorder that causes unprovoked seizures from the temporal lobe. Temporal lobe epilepsy is the most common type of focal onset epilepsy among adults. Seizure symptoms and b ...
,
status epilepticus
Status epilepticus (SE), or status seizure, is a medical condition with abnormally prolonged seizures. It can have long-term consequences, manifesting as a single seizure lasting more than a defined time (time point 1), or 2 or more seizures over ...
and
chronic fatigue syndrome
Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a disabling Chronic condition, chronic illness. People with ME/CFS experience profound fatigue that does not go away with rest, as well as sleep issues and problems with memory ...
.
References
External links
Newly Found Herpes Virus Is Called Major Cause of Illness in Young ''New York Times''
HHV-6 Foundation*
Virus Pathogen Database and Analysis Resource (ViPR): ''Herpesviridae''ICTV
{{Taxonbar, from=Q3512107
Pediatrics
Betaherpesvirinae
Virus genera