Infectious Agents Aetiology Flashcards
What are the main 3 viruses which are associated with malignancy of the oral cavity?
Human papilloma virus (HPV)
Epstein-barr virus (EBV) (HHV4)
Human Immunodeficiency virus (HIV)
What are the 5 types of HPV (human papilloma virus)
- alpha - associated with the skin
- beta - associated with the mouth
- gamma
- mu
- nu
What are the most common lesions that are HPV associated in the mouth?
Papilloma’s
Are papillomas malignant?
no they are benign
High risk types of HPV cause what cancers?
- cervical
- anal
- oropharyngeal
- vaginal
- vuvlar
- penile
How is HPV spread?
through direct sexual contact
describe the structure of HPV
papillomavirys particles are a single molecule of double-stranded, circular DNA, contained in a capside
What are the high risk HPV associated with head and neck cancers?
HPV 16 and HPV 18
What genes in HPV 16 are oncogenic?
E6 and E7 - target tumour suppresor genes
What are the low risk HPV types?
HPV 6 and HPV11
How are E6 and E7 (in high risk HPV) ocogenic?
E6 binds to p53 and marks it for destruction by the ubiquitin pathway
E7 binds and inactivated human tumour suppressor gene product, retinoblastoma protein (pRB)
What makes the low risk HPV different from the high risk?
They have no E6 products (which knock out p53)
and no binding of PDZ domain products
What are the 2 benign oral HPV lesion?
Papilloma
Condylomota
What are the risk factors for HPV?
- number of sexual partners
- weakened immune system
What tests do they use for HPV detection?
- P16 staining - increase of p16 when p53 and pRB are targetted
- In-sity hybridisation - looking for HPV RNA or DNA in the cells - stains dark brown
What are the 3 vaccines available for HPV
- quadrivalent gardasil (HPV 6, 11, 16, 18)
- bivalent cervarix (16 and 18)
- nonvalent gardasil (16, 18, 31, 33, 45, 52, and 58)
all 2 dose vaccines, second dose 6-12 months after the first
Who gets the HPV vaccine
from sep 19, UK girls and boys ages 11 and 12
13-26 if they havent received the vaccine already
Men who have sex with men were eligible up to 45 to get one
What did HPV studies in australia show?
HPV rate dropped with vaccination
What did HPV studies in sweden show?
risk of cervical cancer was 63% lower in HPV vaccinated women than non
What conditions can EBV cause?
- mononucleuosis (MONO)
- lymphoma
- nose and throat cancers
How is EBV transmitted?
Most commonly spread through saliva but can also be spread through other bodily fluids during sexual contact, blood transfusions and organ transplantations
What is the cure for EBV
there is no cure for EBV, but symptoms should go away after 2-4 weeks and it remains inactive
What is the vaccine for EBV?
there is no vaccination or treatment
EBV belongs to there human herpes virus family, what subtype does it belong to?
The gamma subtype
