HPV virus 

HPV (Human Papillomavirus) is a double – stranded circular DNA virus belonging to the genus Papillomavirus of the family Papillomaviridae. The following is a detailed introduction to the HPV virus:

I. Virus Structure

• The HPV virus is composed of a protein capsid and the viral genomic DNA at the core. The protein capsid mainly serves to protect the viral genome, enabling it to survive in the environment outside the host and playing an important role when entering host cells.

II. Virus Typing

• There are multiple subtypes of HPV. Currently, more than 200 HPV genotypes are known. According to their association with cancer development, they can be divided into high – risk and low – risk types.
  • High – risk HPV: It includes types such as HPV16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68. Long – term persistent infections with these types are closely related to the occurrence of various cancers, such as cervical cancer, anal cancer, penile cancer, vulvar cancer, and vaginal cancer. For example, HPV16 and 18 are the main types leading to cervical cancer, and about 70% of cervical cancer cases are related to infections with these two types.
  • Low – risk HPV: For example, types such as HPV6 and 11 mainly cause benign lesions like genital warts (condyloma acuminata). Although they generally do not develop into cancers, they can bring physical discomfort and psychological pressure to patients and are contagious.

III. Transmission Routes

• Sexual Transmission: This is the most important transmission route of HPV. During sexual intercourse, skin – to – mucosa contact enables the virus to spread from an infected person to a sexual partner. Even if condoms are used, HPV can infect areas not covered by condoms, such as the scrotum and labia, and transmission may still occur.
• Mother – to – child Transmission: Pregnant women infected with HPV may transmit the virus to newborns during childbirth. Newborns may be infected with HPV when passing through the birth canal, resulting in diseases such as laryngeal papillomatosis.
• Close – contact Transmission: HPV can also be transmitted through direct skin – to – skin contact. For example, when family members share personal items such as towels and clothes, if one of them is infected with HPV, others are at risk of infection.

IV. Symptoms of Infection

• Genital Warts: Low – risk HPV infections usually lead to the appearance of genital warts. In men, they are more common in areas such as the penis, scrotum, and perianal region. In women, they are more common in areas such as the labia majora and minora, vaginal orifice, urethral orifice, cervix, and perianal region. Genital warts appear as single or multiple papillary, cauliflower – like, or cockscomb – like growths, which are soft in texture, sharp at the top, and moist on the surface. Patients may feel itching, pain, or a foreign – body sensation.
• Cervical Lesions and Cervical Cancer: Persistent infections with high – risk HPV may lead to cervical intraepithelial neoplasia (CIN), a precancerous lesion. As the disease progresses, it may further develop into cervical cancer. Early – stage cervical cancer may have no obvious symptoms. As the disease progresses, symptoms such as irregular vaginal bleeding, increased and foul – smelling vaginal discharge, and post – coital bleeding may occur.

V. Prevention and Treatment

• Prevention:
  • Vaccination: HPV vaccines are an effective means of preventing HPV infections. Currently, there are bivalent, quadrivalent, and nonavalent vaccines, which target different types of HPV respectively. For example, the bivalent vaccine mainly targets HPV16 and 18 and can prevent about 70% of cervical cancers. The quadrivalent vaccine, based on the bivalent vaccine, adds prevention of HPV6 and 11 and can prevent genital warts simultaneously. The nonavalent vaccine can prevent infections with more types of HPV.
  • Safe Sexual Behavior: Although using condoms correctly cannot completely prevent HPV transmission, it can reduce the risk of infection. At the same time, reducing the number of sexual partners also helps prevent HPV infections.
  • Personal Hygiene: Maintaining good personal hygiene habits and avoiding sharing personal items such as towels, bath towels, and underwear with others can reduce the chances of HPV transmission.
• Treatment:
  • Treatment of Genital Warts: For genital warts, methods such as drug treatment (e.g., topical drugs like podophyllotoxin and imiquimod), physical treatment (e.g., cryotherapy, laser therapy, electrocautery therapy, etc.), or surgical resection can be used.
  • Treatment of Cervical Lesions and Cervical Cancer: For cervical intraepithelial neoplasia, observation, physical treatment (e.g., cryotherapy, laser, microwave, etc.), or surgical treatment (e.g., cervical conization) can be adopted according to the degree of the lesion. For cervical cancer, treatment methods include surgery, radiotherapy, chemotherapy, etc. The specific treatment plan needs to be determined comprehensively based on factors such as the patient’s condition, age, and fertility requirements.