Viral infections of the orofacial tissues Flashcards
Give some key features of a virus
- They are obligate parasites
- They require host cells for replication and survival
- Most are fragile
How do viruses bind to epithelial cells
Via the protein antigens displayed in their envelope
How do viruses replicate
- New virus particles are assembled inside the host cells
2. Large number of viral particles are produced in side the cell
How do new virus particles leave the host cells
Due to large number of viral particles inside the cell host lysis occurs resulting in viral particles circulating the host
What can viruses lead to after cell death
Vesicle. pustule and crusted lesion formation eg cold sores
A local systemic inflammatory response can also be set up
How can we detect viral infections in the lab
- Swabs of fluid collection will be needed first
- Any organisms present will be cultured
- once enough particles/ organisms are grown then microscopy can be undertaken to identify them
- Can use PCR techniques to identify viral DNA or RNA
How do we identify viruses
By looking at their viral antigens
What technique do we use to identify viral DNA or RNA
PCR
What are the problems with anti viral therapy
Most drugs drugs are toxic to viruses and the host cells as viruses use host DNA to manufacture more of themselves so you will be attack host materials
Give examples of antiviral therapy
- aciclovir topical and oral
- penciclovir topically
- Valaciclovir
- Famciclovir
Is the human herpes virus (HHV) a DNA or RNA virus
DNA viruses
Describe the human herpes virus in its primary infection
May be asymptomatic which leads to latency with or without viral shedding
This can cad to reactivation but not in all patients
Describe how herpes simplex virus 1 (HSV1) presents clinically
Predominantly oral lesions - ‘primary gingivostomatitis”
Describe how herpes simplex virus 2 (HSV2) presents clinically
Predominantly genital lesions - primary genital herpes
genital herpes lesions are similar to the oral ones in appearance -
Name the human herpes virus types that are only naturally found in humans
HSV 1
HSV 2
How does HSV1 and HSV2 spread
Spread via direct contact
What happens to cells during primary HSV infection
- Direct contact with infected secretions leads to deep epithelial cells becoming infected
- Infected cells undergo lysis
- Inflammation occurs leading to oedema
- Thin walled vesicles form and these are full of virus particles
Describe the vesicles formed during primary HSV infection
They are fragile, rupture easily then crusting as healing follows
Talk through the signs and symptoms of Primary herpetic gingivostomatitis
- Pyrexia, sore throat, fractious infants
- Ulcers due to oral vesicles rapidly bursting
- Gingival inflammation which can make eating and speaking difficult
- Small children may drool, have bad breath
How can we manage Primary herpetic gingivostomatitis
- Reassurance and explanation
- Symptomatic relief including good oral hygiene
- Keep hydrated
- Take paracetamol for pyrexia
- SLS free toothpastes and mouthwashes
- Bland soft diet
- 0.15% benzine hydrochloride mouthwash or spray
HSVs are N_________
neurotropic
What do we mean by HSVs are neurotropic
Means that once infection has occurred, they forever live on in the sensory neurones
What can trigger reactivation of latent infection
- UV light exposure
- Wind
- Stress
- Steroids
- Menstruation
- Fever
- surgery
- Other illness
How can we manage cold sores
- Don’t share towels/ bedding when you have active lesion
- Topical acyclovir 5% applied every 4hours
- Topical penciclovir 1% cream applied every 2 hours
What are cold sores also called
Herpes Labialis
How do we manage recurrent intraoral herpes lesions
- Explanation
- Chlorhexidene mouthwash or spray
- DO NOT use topical antivirals inside the mouth
Give examples of viral infections
- human herpes virus
2. Varicella zoster virus
How is the Varicella zoster virus spread
By droplets from the nasopharyngeal secretions or vesicle fluid
What is primary infection with Varicella called
Chicken pox
What is chicken pox
An upper respiratory tract induction with Varicella zoster virus