Human polyomavirus 2: Difference between revisions

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'''Human polyomavirus 2''' ('''HPyV2'''), also known as '''BK virus''', is a member of the [[Polyomaviridae]] family of viruses. It is a [[DNA virus]] that is ubiquitous in the human population, typically infecting individuals in early childhood and remaining latent in the body. The virus is named after the initials of the patient from whom it was first isolated in 1971.
{{DISPLAYTITLE:Human Polyomavirus 2}}


== History ==
== Overview ==
[[File:Human_polyomavirus_2_Wharton_plosone_2016.png|thumb|right|Electron micrograph of Human Polyomavirus 2]]
'''Human Polyomavirus 2''', also known as '''JC virus''', is a type of [[polyomavirus]] that infects humans. It is a member of the [[Polyomaviridae]] family and is known for its ability to cause [[progressive multifocal leukoencephalopathy]] (PML), a rare and often fatal demyelinating disease of the central nervous system.


Human polyomavirus 2 was first discovered in 1971 in the urine of a renal transplant patient named B.K. The virus was subsequently named after the patient's initials. Since its discovery, HPyV2 has been the subject of extensive research due to its association with severe disease in immunocompromised individuals.
== Discovery and Classification ==
Human Polyomavirus 2 was first isolated in 1971 from the brain of a patient with PML. It is classified under the genus ''[[Betapolyomavirus]]'' within the family Polyomaviridae. The virus is named "JC" after the initials of the patient from whom it was first isolated.


== Virology ==
== Structure ==
The virus is a small, non-enveloped virus with a circular double-stranded [[DNA]] genome. The capsid is icosahedral in shape and composed of 72 capsomers. The genome encodes for several proteins, including the [[T-antigen]]s, which are crucial for viral replication and transformation.


HPyV2 is a small, non-enveloped virus with a circular, double-stranded DNA genome. The virus is part of the [[Polyomaviridae]] family, which also includes the closely related [[Human polyomavirus 1|JC virus]]. The genome of HPyV2 encodes for six proteins, three of which are involved in viral replication and three of which are involved in the assembly of the viral capsid.
== Epidemiology ==
Human Polyomavirus 2 is widespread in the human population, with seroprevalence rates ranging from 50% to 80% in adults. Primary infection typically occurs in childhood and is usually asymptomatic. The virus remains latent in the kidneys and other tissues.


== Epidemiology ==
== Pathogenesis ==
In immunocompromised individuals, such as those with [[HIV/AIDS]] or those undergoing immunosuppressive therapy, the virus can reactivate and cause PML. The reactivation leads to the destruction of [[oligodendrocytes]], resulting in demyelination and neurological symptoms.


HPyV2 is ubiquitous in the human population, with seroprevalence rates of up to 90% reported in adults. The virus is typically acquired in early childhood and remains latent in the body, particularly in the urinary tract. Reactivation of the virus can occur in immunocompromised individuals, leading to severe disease.
== Clinical Manifestations ==
The primary disease associated with Human Polyomavirus 2 is progressive multifocal leukoencephalopathy. Symptoms of PML include:
* Weakness or paralysis
* Vision problems
* Cognitive impairment
* Speech difficulties


== Clinical significance ==
== Diagnosis ==
Diagnosis of Human Polyomavirus 2 infection is typically made through detection of viral DNA in the [[cerebrospinal fluid]] using [[polymerase chain reaction]] (PCR). Brain imaging, such as [[MRI]], can also support the diagnosis by revealing characteristic lesions.


In immunocompetent individuals, infection with HPyV2 is typically asymptomatic. However, in immunocompromised individuals, such as those with HIV/AIDS or those who have undergone organ transplantation, reactivation of the virus can lead to severe disease. This includes [[Polyomavirus-associated nephropathy|polyomavirus-associated nephropathy]] (PVAN), a serious condition that can lead to graft loss in kidney transplant recipients, and [[hemorrhagic cystitis]], a condition characterized by inflammation and bleeding in the bladder.
== Treatment ==
There is currently no specific antiviral treatment for Human Polyomavirus 2. Management of PML involves restoring immune function, such as through antiretroviral therapy in HIV-positive patients. Experimental treatments are being investigated, but none have been conclusively proven effective.


== Treatment and prevention ==
== Prevention ==
Preventive measures focus on maintaining immune function to prevent reactivation of the virus. This includes careful management of immunosuppressive therapies and monitoring of at-risk patients.


There is currently no specific antiviral treatment for HPyV2 infection. Management of the infection in immunocompromised individuals typically involves reducing immunosuppression, if possible. Prevention of HPyV2 infection is difficult due to the high prevalence of the virus in the population. However, regular monitoring of viral load in at-risk individuals can help to identify reactivation of the virus and guide management decisions.
== Related Pages ==
* [[Polyomavirus]]
* [[Progressive multifocal leukoencephalopathy]]
* [[Immunocompromised host]]


[[Category:Virology]]
[[Category:Polyomaviruses]]
[[Category:DNA viruses]]
[[Category:Viral diseases]]
[[Category:Polyomaviridae]]
{{Virus-stub}}

Revision as of 05:15, 16 February 2025


Overview

File:Human polyomavirus 2 Wharton plosone 2016.png
Electron micrograph of Human Polyomavirus 2

Human Polyomavirus 2, also known as JC virus, is a type of polyomavirus that infects humans. It is a member of the Polyomaviridae family and is known for its ability to cause progressive multifocal leukoencephalopathy (PML), a rare and often fatal demyelinating disease of the central nervous system.

Discovery and Classification

Human Polyomavirus 2 was first isolated in 1971 from the brain of a patient with PML. It is classified under the genus Betapolyomavirus within the family Polyomaviridae. The virus is named "JC" after the initials of the patient from whom it was first isolated.

Structure

The virus is a small, non-enveloped virus with a circular double-stranded DNA genome. The capsid is icosahedral in shape and composed of 72 capsomers. The genome encodes for several proteins, including the T-antigens, which are crucial for viral replication and transformation.

Epidemiology

Human Polyomavirus 2 is widespread in the human population, with seroprevalence rates ranging from 50% to 80% in adults. Primary infection typically occurs in childhood and is usually asymptomatic. The virus remains latent in the kidneys and other tissues.

Pathogenesis

In immunocompromised individuals, such as those with HIV/AIDS or those undergoing immunosuppressive therapy, the virus can reactivate and cause PML. The reactivation leads to the destruction of oligodendrocytes, resulting in demyelination and neurological symptoms.

Clinical Manifestations

The primary disease associated with Human Polyomavirus 2 is progressive multifocal leukoencephalopathy. Symptoms of PML include:

  • Weakness or paralysis
  • Vision problems
  • Cognitive impairment
  • Speech difficulties

Diagnosis

Diagnosis of Human Polyomavirus 2 infection is typically made through detection of viral DNA in the cerebrospinal fluid using polymerase chain reaction (PCR). Brain imaging, such as MRI, can also support the diagnosis by revealing characteristic lesions.

Treatment

There is currently no specific antiviral treatment for Human Polyomavirus 2. Management of PML involves restoring immune function, such as through antiretroviral therapy in HIV-positive patients. Experimental treatments are being investigated, but none have been conclusively proven effective.

Prevention

Preventive measures focus on maintaining immune function to prevent reactivation of the virus. This includes careful management of immunosuppressive therapies and monitoring of at-risk patients.

Related Pages