Papillomavirus and Polyomavirus

What family do papillomaviruses belong to?

Papillomaviridae.

What type of genome do papillomaviruses have?

Circular double-stranded DNA.

When were papillomaviruses first recognized as causing cancer?

In 1935, they were discovered to cause cancer in rabbit test subjects.

How many genera are papillomaviruses divided into?

39 genera.

What is the typical structure of a papillomavirus virion?

Non-enveloped, spherical, 55 nm in diameter, with icosahedral symmetry.

How does papillomavirus enter the host cell?

Through microtrauma to interact with an unknown secondary receptor of a basal keratinocyte.

What happens to the papillomavirus genome during replication?

It enters the nucleus to begin production of 10-200 episomal copies of viral genomic DNA.

What are koilocytes?

Resulting cells that are enlarged with smudgy blue-grey cytoplasm and shrunken nuclei surrounded by a clear halo.

What are the E proteins of papillomavirus associated with?

Influencing cell growth and division; E6 degrades p53, E7 degenerates retinoblastoma, and E5 alters growth through interaction with PDGF beta-receptor.

How can the host’s immune response act against papillomavirus?

Antibodies can prevent subsequent infections, as seen with HPV vaccines.

What is one method to diagnose papillomavirus infections?

Cytopathologic features and immunohistochemistry.

What technology can be used for molecular diagnosis of papillomavirus?

PCR amplification and in situ hybridization.

What are some diseases associated with papillomavirus in cattle?

Fibropapilloma and squamous papilloma.

Which polyomavirus is known to cause serious diseases in immunocompromised individuals?

JC polyomavirus and BK polyomavirus.

What is a common characteristic of polyomavirus infections in the general population?

Most polyomavirus infections don’t cause any symptoms and can persist without causing problems.

What is the role of the ALTO gene in polyomaviruses?

It allows for the overprinting of DNA segments to express a second protein.

Which polyomavirus is linked to Merkel cell carcinoma in humans?

Merkel cell polyomavirus.

What are major disease symptoms caused by the Goose Hemorrhagic Polyomavirus in young geese?

Hemorrhagic nephritis and depletion of lymphocytes.

What virus as a model was discovered to transform cultured cells and lead to the understanding of cancer?

Murine polyomavirus (MPyV) and Simian virus 40 (SV40).

What are the two genera of mammalian polyomaviruses currently proposed?

Orthopolyomaviridae and Wukipolyomaviridae.

What are the common methods by which laboratory animals can be affected by polyomaviruses?

Infection and subsequent tumor formation in immunodeficient conditions.

What types of animals have been discovered to carry polyomaviruses?

Monkeys, mice, rats, hamsters, rabbits, and bats.

What is the main vector for transmitting papillomaviruses?

Human skin and mucosal contact during activities like sexual intercourse.

What is the significance of the E7 protein in papillomavirus?

It promotes cellular division by degrading the retinoblastoma protein.

What are the common strains of HPV known to cause cervical cancer?

HPV types 16 and 18.

How can HPV infections be prevented?

Through vaccination, safe sex practices, and regular screenings.

What type of cells do papillomaviruses typically infect?

Keratinocytes in the basal layer of the epithelium.

What is the role of the L1 protein in papillomavirus?

It is a major capsid protein essential for the formation of the viral capsid.

What laboratory technique can differentiate high-risk HPV types?

HPV typing assays through PCR.

Which HPV vaccines are currently available?

Gardasil and Cervarix.

How long can papillomaviruses persist in the body without causing symptoms?

They can persist for months to years before causing lesions or symptoms.

What type of environment do papillomaviruses thrive in on the skin?

A moist environment with microtrauma to the skin barriers.

What is HPV?

HPV stands for human papillomavirus, a group of more than 200 related viruses.

How is HPV transmitted?

HPV is transmitted through skin-to-skin contact, primarily during sexual intercourse.

What are the symptoms of HPV?

Many HPV infections are asymptomatic; however, some can cause warts or lead to cancers.

What cancers are most commonly associated with HPV?

Cervical cancer is the most well-known, but HPV is also linked to anal, oropharyngeal, and other genital cancers.

Can HPV be treated?

There is no cure for HPV, but the health problems it causes can be treated.

What are low-risk HPV types?

Low-risk HPV types, like 6 and 11, can cause genital warts but are unlikely to cause cancer.

What are high-risk HPV types?

High-risk HPV types, like 16 and 18, are associated with various cancers, including cervical cancer.

What is the Pap smear?

A Pap smear is a screening test for cervical cancer that detects abnormal cells in the cervix.

What is the HPV vaccine?

The HPV vaccine protects against the most common high-risk and low-risk HPV types.

What age group is recommended to receive the HPV vaccine?

The vaccine is recommended for preteens aged 11 to 12 years, but can be given up to age 26.

What is Gardasil?

Gardasil is a type of HPV vaccine that protects against HPV types 16, 18, 6, and 11.

What is Cervarix?

Cervarix is an HPV vaccine that primarily protects against HPV types 16 and 18.

How effective are HPV vaccines?

HPV vaccines have been shown to be highly effective in preventing infections and related diseases.

What is the usual course of HPV infection?

Most HPV infections clear on their own within two years; some persist and may cause problems.

How does smoking affect HPV?

Smoking can weaken the immune system and increases the risk of cervical cancer in HPV-positive women.

What role does the immune system play in HPV infection?

A strong immune response can help clear HPV infections, whereas a weakened system may lead to persistence.

What complications can arise from untreated HPV infections?

Untreated infections can lead to genital warts or various cancers, particularly in women.

Can men get HPV-related cancers?

Yes, men can develop HPV-related cancers, including penile and oropharyngeal cancers.

What is the significance of HPV typing?

HPV typing identifies the specific type of HPV and helps assess cancer risk.

How often should women get Pap smears?

Women aged 21-29 should have Pap smears every three years; after 30, they may switch to co-testing every five years.