E12: Human Papilloma Virus- Cancer Causing and Condom Resistant

The human papilloma virus is a virus that is transmitted between humans by skin-to-skin contact not limited to kissing and sexual intercourse. HPV is a Baltimore Class I virus. The genome is double stranded circular DNA surrounded by an icosahedral capsid. The virus infects basal epithelial cells (dividing cells) through microtears in the epidermis. The virus interacts with a receptor, and likely a co-receptor and enters the cell through endocytosis. As the viral capsid disassembles in the endosome, the viral DNA is transferred to the nucleus via an interaction with L2 making the host cells be infected.

There are many types of HPV of which over 200 different types are known to cause different health problems in humans. This post focuses on the types of HPV that can be spread through sex behaviour.

MODE OF TRANSMISSION

One can get infected with HPV if their mouth or genitals touch the genitals of someone who is infected. This mainly happens through oral, vaginal, or anal sex. But HPV can also be spread through close genital-to-genital contact, even without having penetrative sex. Having multiple sex partners confers a higher chance of getting an HPV infection.

SYMPTOMS

Most people with HPV do not know that they have the infection. So it is easy to spread to partners without realizing it.

Very often, the infection will clear on its own. In most people, their immune system attacks the virus and clears the HPV infection, typically within 2 years. But in some people, the infection doesn’t go away. If this happens, it can lead to health problems.

People with a long-lasting HPV infection have a higher chance of getting other health problems.

RELATION BETWEEN HPV AND CANCERS

The HPV types that are known to cause cancer are referred to as high risk HPV while those that have never been identified as causing cancer are called low risk HPV. For example:

• Cervical, Vaginal, Penile Cancer– A high risk HPV infection in the genitals can cause cancer of the cervix (cervical cancer), vagina (vaginal cancer), or penis (penile cancer). Other types of low risk HPV can cause genital warts.
• Anal Cancer– A high risk HPV infection around the anus can cause cancer of the anus (anal cancer). Other types of low risk HPV can cause warts.
• Mouth, Throat Cancer– A high risk HPV infection in the mouth and throat can cause cancer of the mouth and throat. Other types of low risk HPV can cause warts.

TREATMENT AND PREVENTION

Once you have HPV, it is not possible to get rid of it with medicines.

The best way to protect against HPV is to get the HPV vaccine. The vaccine only works if it is given before a person gets infected with HPV.

NOTE: Condoms do not protect against HPV. That’s because the virus can live on skin that is not covered by a condom. But condoms are still an important way to protect yourself against other sexually transmit-ted diseases.

BASELINE

• With particular focus on cervix cancer, which is the leading cause of all cancer related deaths in Kenya and the second most common cancer in Kenya, HPV testing is important as more than 99% of cervical cancers are caused by HPV
• The current WHO cervix cancer screening guidelines and Ministry of Health Kenya National Cancer Screening Guidelines both recommend HPV testing as the primary (preferred) screening method for cervix cancer in all eligible women of age 30 years and above.
• The cervix cancer screening HPV test is a PCR based test performed in the laboratory.
• The sample can be collected by your doctor in a procedure that is similar to normal pap smear collection
• Sexually active women younger than 30 years should undergo cervical cancer screening through regular Pap tests (sometimes called “Pap smears”) starting at age 21.