Human Papillomavirus Infection

Overview

Human papillomavirus infection (HPV infection) is caused by a DNA virus from the Papillomaviridae family. It is one of the most common sexually transmitted infections globally, with most people being infected at some point in their lives. HPV can cause various conditions ranging from asymptomatic infections to warts and cancers.

Signs and Symptoms

Warts

HPV can cause noncancerous skin growths called warts. These can appear on various parts of the body, including hands, feet, and genitals. Common warts have a characteristic cauliflower-like surface and are typically slightly raised. Plantar warts, found on the soles of the feet, grow inward and can cause pain when walking. Subungual and periungual warts form under and around the fingernail, respectively, making them difficult to treat.

Genital Warts

Genital warts, medically known as condylomata acuminata, are the most easily recognised sign of genital HPV infection. They are commonly caused by HPV types 6 and 11. These warts can be sexually transmitted and often appear as small bumps or groups of bumps in the genital area.

Cancer

HPV infection is linked to several types of cancers, including cervical, vulvar, vaginal, penile, anal, and oropharyngeal cancers. Nearly all cases of cervical cancer are associated with HPV, particularly types 16 and 18, which contribute to 70% of cases. Persistent infection with high-risk HPV types can lead to cancer development due to the integration of the viral genome into the host DNA, promoting tumour growth.

Diagnosis

Cervical Testing

Cervical cancer screening is very important for early detection and includes the Papanicolaou test (Pap smear) and HPV DNA testing. The American Cancer Society recommends co-testing with both the HPV test and the Pap test every five years for women aged 30-65.

Mouth Testing

Screening for oropharyngeal cancer involves visual examination and biopsy of exfoliated cells or tissues. The National Comprehensive Cancer Network recommends testing for HPV in oropharyngeal cancer cases.

Testing in Men

Although there are limited tests available for men, studies have shown HPV presence on fingers, mouth, saliva, anus, urethra, urine, semen, blood, scrotum, and penis. Self-collection methods have been found effective for detecting HPV in men.

Prevention

Vaccines

HPV vaccines like Gardasil, Gardasil 9, and Cervarix can prevent infection by the most common types of HPV. These vaccines are most effective when administered before the onset of sexual activity, typically recommended for individuals aged 9-13. Gardasil 9, a nonavalent vaccine, provides protection against nine HPV types, preventing about 90% of cervical, vulvar, vaginal, and anal cancers.

Condoms

Condoms can reduce the risk of genital HPV infection, but they do not provide complete protection as HPV can infect areas not covered by the condom.

Disinfection

HPV is resistant to most common disinfectants, including glutaraldehyde. Effective disinfection methods include diluted sodium hypochlorite bleach, UV disinfection, strong hydrogen peroxide solutions, and chlorine dioxide wipes.

Management

There is no specific treatment for HPV infection, but the immune system clears the virus naturally in most cases within two years. Follow-up care is essential for managing HPV-related conditions, and screening has significantly reduced the incidence and mortality of cervical cancer.

Epidemiology

HPV infection is highly prevalent worldwide, with 12% of women being HPV-positive. The highest rates are among younger women, particularly in Sub-Saharan Africa and Eastern Europe. In the United States, HPV is the most common sexually transmitted infection, with most sexually active individuals acquiring it at some point in their lives.

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Self-assessment MCQs (single best answer)

HPV is a DNA virus from which family?

What types of HPV are most commonly associated with genital warts?

Which type of cancer is nearly always associated with HPV infection?

Cervical cancer screening in women aged 30-65 typically involves which of the following tests?

What is the primary recommended age group for HPV vaccination?

Which of the following is an effective method for disinfecting surfaces contaminated with HPV?

What is the primary way HPV is transmitted?

What is the natural course of HPV infection in most cases?

Which HPV types are most commonly associated with cervical cancer?

In which regions are the highest rates of HPV infection found?