The presentation covers all major aspects of the virus including oncogenicity, Structure, Pathogenesis. It also covers preventive measures and vaccines. This presentation is targeted to students at bachelors level for allied/optional microbiology paper

1. Human
papilloma
virus
Human papillomavirus is the
most common sexually
transmitted infection. Most
sexually active men and women
being exposed to the virus at
some point during their lifetime

2. Structure
• small, non-enveloped, icosahedral DNA
viruses that have a diameter of 52–55
nm.
• single double-stranded DNA molecule of
about 8000 base-pairs (bp) that is bound
to cellular histones
• a protein capsid composed of 72
pentameric capsomers.
• capsid contains two structural proteins —
late 1 and Late 2 — which are both virally
encoded.

3. Classification
• the International Committee on the Taxonomy of
Viruses (ICTV) as two separate families —
Papillomaviridae and Polyomaviridae.
• HPV is divided into High risk HPV and Low risk HPV. Low-
risk types cause warts and high-risk types can cause
lesions or cancer.

4. Pathogenesis
• HPV infection is limited to the basal cells of stratified
epithelium
• The virus cannot bind to live tissue
• it infects epithelial tissues through micro-abrasions or other
epithelial trauma that exposes segments of the basement
membrane
• HPV virion associates with receptors such as alpha integrins,
laminins, and annexin A2

5. Pathogenesis
How HPV causes Cancer?
• Early proteins (E): E6/E7 proteins inactivate two tumor suppressor
proteins, p53 (inactivated by E6) and Retinoblastoma (inactivated by
E7)
• E7 acts as the primary transforming protein. E7 competes for
retinoblastoma protein binding, freeing the transcription factor E2F to
transactivate its targets, thus pushing the cell cycle forward.
• E6 in association with host E6-associated protein, which has ubiquitin
ligase activity, acts to ubiquitinate p53, leading to its proteosomal
degradation

6. Pathogenesis
How HPV causes Cancer?

7. Symptoms
• HPV may not cause symptoms at once, but they can appear years later. Some types can
lead to warts, while others can cause cancer.
Warts
• Common symptoms of some types of HPV are warts, especially genital warts.
• Genital warts may appear as a small bump, cluster of bumps, or stem-like protrusions.
They commonly affect the vulva in women, or possibly the cervix, and the penis or
scrotum in men. They may also appear around the anus and in the groin.
• They can range in size and appearance and be large, small, flat, or cauliflower shaped,
and may be white or flesh tone.
• HPV6 and HPV11 are common causes of genital warts and laryngeal papillomatosis.

8. Symptoms
Other warts associated with HPV include common warts, plantar, and
flat warts.
• Common warts - rough, raised bumps most commonly found on
the hands, fingers, and elbows.
• Plantar warts - described as hard, grainy growths on the feet; they
most commonly appear on the heels or balls of the feet.
• Flat warts - generally affect children, adolescents, and young
adults; they appear as flat-topped, slightly raised lesions that are
darker than normal skin color and are most commonly found on
the face, neck, or areas that have been scratched.

9. Symptoms

10. Symptoms
• Anogenital warts
• Anal dysplasia (lesions) : pre cancerous condition in anal canal
• Genital cancers
• Epidermodysplasia verruciformis (Treeman syndrome, a high risk skin cancer)
• Focal epithelial hyperplasia (benign neoplamic condition in mouth)
• Mouth papillomas (benign epithelial tumor)
• Oropharyngeal cancer
• Laryngeal papillomatosis (aerodigestive benign cancer)

11. Symptoms
Cancer
• Other types of HPV can increase the risk of developing cancer. These cancers include
cancer of the cervix, vulva, vagina, penis, anus, and oropharynx, or the base of the
tongue and tonsils. It may take years or decades for cancer to develop.
• early all cervical cancer is due to HPV with two types, HPV16 and HPV18, accounting
for 70% of cases
• These cancers in common involve sexually transmitted infection of HPV to the
stratified epithelial tissue.
• Individuals infected with both HPV and HIV have an increased risk of developing
cervical or anal cancer.

12. Symptoms: Cervical Cancer
As in many cancers, there may be no signs or symptoms of
cervical cancer until it has progressed to a dangerous stage.
However, if symptoms do occur they may include:
• Abnormal vaginal bleeding
• Pain in very advanced stages
• Any bleeding from the vagina other than during menstruation.
• Abnormal vaginal discharge

13. Transmission
• HPV is transmitted through intimate skin-to-skin contact.
• having vaginal, anal, or oral sex with someone who has the virus.
• It is most commonly spread during vaginal or anal sex.
• common that nearly all men and women get it at some point in their
lives.
• can be passed even when an infected person has no signs or symptoms.
• can develop symptoms years after being infected, making it hard to
know when you first became infected.
In most cases, HPV goes away on its own and does not cause any health problems. But when
HPV does not go away, it can cause health problems like genital warts and cancer.

14. Diagnosis
The traditional methods of viral diagnosis such as electron
microscopy, cell culture, and certain immunological methods are
not suitable for HPV detection. HPV cannot be cultured in cell
cultures.
The important methods to diagnose HPV infection are:
• Colposcopy and acetic acid test
• Biopsy
• DNA test (PCR, Southern Blot Hybridization, In Situ Hybridization)
• Pap smear

15. Diagnosis
Colposcopy: a procedure that allows illuminated
stereoscopic and magnified viewing of the cervix.
PCR-based methods: HPV DNA can be amplified
selectively by a series of reactions that lead to an
exponential and reproducible increase in viral sequences
present in the biological specimen.
serological assays: ELISA or western blot analysis

16. Diagnosis
Biopsy: If the biopsy results show pre-cancer (dysplasia) or cancer,
then treatment is recommended. The dysplasia may be mild,
moderate, or severe.
PAP smear or PAP test: It is a screening test. Apart from
premalignant and malignant changes, viral infections like HPV
infection and Herpes can also be detected.
Acetic acid Test: A vinegar solution applied to HPV-infected genital
areas turns them white. This may help in identifying difficult-to-see
flat lesions.

17. Diagnosis: PAP smear test
• Early precancerous changes detected on the Pap smear
• A woman may have cervical cancer and not know it because she may
not have any symptoms.
• A Pap smear is usually part of a pelvic exam and accompanied by a
breast exam
• A sample of mucus and cells will be obtained from the cervix and
endocervix using a wooden scraper or a small cervical brush or broom.
• the sample is rinsed into a vial and sent to a lab for slide preparation
and examination.

18. Treatment
There is currently no specific treatment for HPV infection.
However warts can be treated.
• Salicylic acid. Over-the-counter treatments that contain salicylic acid work by removing
layers of a wart a little at a time.
• Imiquimod (Aldara, Zyclara). This prescription cream might enhance your immune
system's ability to fight HPV. Common side effects include redness and swelling at the
application site.
• Podofilox (Condylox). Another topical prescription, podofilox works by destroying
genital wart tissue. Podofilox may cause pain and itching where it's applied.
• Trichloroacetic acid. This chemical treatment burns off warts on the palms, soles and
genitals. It might cause local irritation.

19. Treatment
Surgical and other procedures
If medications don't work the following methods can e use to
remove warts
• Freezing with liquid nitrogen (cryotherapy)
• Burning with an electrical current (electrocautery)
• Surgical removal
• Laser surgery
"condom use may reduce the risk for genital human papillomavirus (HPV) infection"

20. Vaccination
Three vaccines are available to prevent infection by some HPV
types. All protect against initial infection with HPV types 16 and 18,
which cause most of the HPV-associated cancer cases.
Gardasil: protects against HPV types 6 and 11, which cause 90% of
genital warts. quadrivalent vaccine
Cervarix: bivalent, and is prepared from virus-like particles (VLP) of
the L1 capsid protein.
Gardasil 9: nonavalent, it has the potential to prevent about 90% of
cervical, vulvar, vaginal, and anal cancers.

21. Prevention
• Vaccination
• Avoid skin-to-skin contact by not having sex with strangers.
• Use condoms and/or dental dams every time you have
vaginal, anal, or oral sex.
• Though condoms and dental dams are not as effective
against HPV as they are against other STDs like chlamydia
and HIV, safer sex can lower your chances of getting HPV.