Human papilloma Viruse(HPV)

Human papilloma Viruse(HPV)
Presentation By:Nathalia Cruz

What is a Virus?
* Exceptionally simple living microbes.
* Contain a single type of nucleic acid (DNA or RNA) and a protein coat.
* Obligatory intracellular parasites.
* Range from 20 to 14.000 nm in length.
* It’s classification is based on type of nucleic acid, strategy for replication, and morphology

HUMAN PAPILLOMA VIRUS

* HPV is the virus that causes warts.
* More than 100 different kinds, 30-some of this cause genital HPV.
* Spread by sexual contact or from mother to baby.
* Genital warts appear 6 weeks to 8 months after contact with an HPV infected person.
* The most common sexually transmitted disease worldwide.
* Certain types of HPV are linked with cervical cancer.
* Divided into 2 subcategories: Genital Warts and Cervical Dysplasia.
* Most people do not know they have it.
* There are high risk and low risk types of it.

HISTORY

* The papillomaviruses are part of the PAPOVAVIRIDAE family of DNA tumor viruses.
* First discovered in the early 40’s.
* Gained notoriety in the early 80’s when it was discovered that some types of HPV caused cervical cancer.

MORPHOLOGY

* Papilloma virus genome is circular covalently closed double stranded DNA of about 8 kbp.
* All PV genes are coded in one of the 2 DNA strands utilizing the alternative splicing for the individual expression of each gene.
* Papillomavirus expression is characterized by a large array of mRNAs cells coding for different genes.
* 55 nm in diameter.

APPEARANCE
MECHANISM OF INFECTION
* All PV exhibit extreme specificity for infection on epithelial cells.
* The papillomavirus epitheliotrophy resides in the interaction of specific transmission factors with the viral regulatory region LCR.
* The infection normally results in hyperproliferation of the host cell and may lead to transformation and immortalization.

GENITAL WARTS

* Sometimes called condylomata acuminata.
* Are soft, moist or flesh colored, and appear in the genital area within weeks or months after infection.
* Sometimes appear in clusters and are either raised or flat, small or large.
* Women: appear in the vulva, cervix, vagina and anus.
* Men: Can appear on the scrotum or penis.

LIFE CYCLE (HPV-16)

* Starts with the infection of the host cell.
* The virus DNA is released within the nucleus
* Numerous cellular transcription factors interact with the non-coding viral regulatory region (LCR), starting transcription of the two hpv-16 transforming early genes (E6 and E7).
* The transforming proteins interact with the cellular antioncogenic regulator p53 disrupting the cell cycle.

LIFE CYCLE
HPV TYPES
HPV GENOMIC ORGANIZATION
HOW HPV CAUSES CANCER
* HPV DNA integrates into the host genome.
* The proteins E6 and E7 are produced from the resultant DNA.
* E6 binds and degrades p53 (a tumor suppressor gene).
* If the DNA is altered, the cell keeps replicating. The mutation rate of the cell increases.
* E7 binds and degrades retinoblastoma (another tumor suppressor gene).
* Retinoblastoma normally keeps the cell from growing too fast or responding to growth stimulators. This inhibitory factor is now lost.
* without these two mechanisms to slow down cell growth and prevent mutation. . .
* Malignant Transformation Occurs.


HPV TREATMENT

* Genital warts can be treated by a doctor and by different methods.
* Podofilox gel: A patient-applied treatment for external genital warts.
* Imiquimod cream: A patient-applied treatment.
* Chemical treatments (including trichloracetic acid and podophyllin), which must be applied by a trained health care provider to destroy warts.
* Cryotherapy: Uses liquid nitrogen to freeze off the warts.
* Laser therapy: Uses a laser beam or intense lights to destroy the warts.
* Electrosurgery: Uses and electric current to burn off the warts.
* Surgery: Can cut away the wart in one office visit .
* Interferon: an antiviral drug, which can be injected directly into warts.

CURE

* There is currently no cure for human papillomavirus.
* Once an individual is infected, he or she carries the virus for life even if genital warts are removed.
* The development of a vaccine against HPV is under way, but is still not available.
* If left untreated, some genital warts may regress on their own.


SOURCES

* http://cinvestav.mx/genetica/MyFiles/Papillomavirus/PAPepi.html
* http://www.life.umd.edu/classroom/bsci424/BSCI223WebSiteFiles/LectureList.htm#LectureList
* WWW.STDSERVICES.ON.NET/STD/WARTS
* http://www.ashastd.org/stdfaqs/hpv.html
* http://www.niaid.nih.gov/factsheets/stdhpv.htm

Human papilloma Viruse.ppt