Oral Viral Infections Flashcards
What size is the human herpes virus?
0.1-0.2um
What size is bacteria?
1-3um
What size are RBCs?
7-8um
What are some characteristics of viruses?
- small size
- simple chemical composition
- no intracellular organelles
- genetic information as DNA or RNA
What are the key stages of replication of the Herpes Simplex virus?
1 = binding
2 = entry
3 = release & nuclear transport
4 = nuclear entry
5 = gene expression
6 = DNA replication
7 = packaging
8 = egress
what is the first principle of laboratory diagnosis?
good history & examination
What are the principles of a lab diagnosis?
- good history & exam
- give provisional diagnosis
- diagnosis from swab
What is an example of a method of specimen retrieval?
viral swab
How is a viral swab taken?
- use flocked swab
- place in molecular sample solution (MSS)
- after immersion remove swab
How are blood samples sent for viral inspection?
- EDTA
What should be included on a virology request form?
- Pt details & clinician details (include phone number)
- clinical details & provisional diagnosis
- date of onset
- patient DOB or CHI number
- specify test you require
How does Herpex Simplex virus look under the SEM microscope?
fried egg appearance
What are some common features of the human herpes virus?
- primary infection –> latency –> secondary infection
What are the clinical features of herpes simples type 1 & 2?
- gingivo stomatitis
- herpes labialis
- keratoconjunctivitis
- herpectic whitlow
- Bell’s palsy
- genital herpes
how common is the herpes simplex virus?
around >90% of population have it
What is the reservoir for the herpes simplex virus?
saliva
What is the route of transmission of the herpes simplex virus?
direct by close person to person contact
When is herpes most commonly occuring?
childhood
How is herpes simplex treated to prevent recurrent infection in difficult cases?
ACV 200mg x 5 daily (chemoprophylaxis)
How is antiviral therapy used to treat herpes simplex infections?
- topical therapy with ACV (aciclovir cream 5%)
- IV therapy for severe & immunosuppressed
What is the incubation period for varicella (chickenpox)?
10-21 days
what are some complications associated with varicella (chickenpox) infections?
- secondary bacterial infections
- pneumonia
- congenital, perinatal/neonatal problems
What are the clinical features of the zoster (shingles) virus?
- vesicles appear in dermatome, representing cranial or spinal ganglia where the virus has been dormant
- affected area may be intensely painful with associated parathesia
What are some complications of the zoster (shingles) virus?
- post herpetic neuralgia
- secondary bacterial infections
- ophthalmic zoster
- ramsay hunt syndrome
What are the steps of infection of the vericella - zoster virus?
- primary infection = infection with varicella zoster virus
- remains latent in the sensory ganglion (trigeminal)
- reactivation of latent virus from sensory ganglion
What is the route of transmission of the varicella-zoster virus?
direct contact
- droplet or airborne spread
In which population is the varicella virus most common?
children
In which population is the zoster virus most common?
elderly & immunocompromised
How is shingles treated?
Aciclover: 800mg Oral x 5 daily for 7 days
How can zoster infection be prevented?
Vaccine - Zostavax
When is Zostavax given?
All people aged 70 + years old
What type of vaccine is Zostavax?
live attenuated virus
What disease does enterovirus infection cause?
hand, food & mouth disease
What are the symptoms of hand foot and mouth disease?
- fever
- runny nose
- sneezing & cough
- skin rash
- mouth blisters
- body & muscle aches
What is the dentally relevant non-polio enterovirus?
Coxsackie virus
How is hand, foot & mouth disease treated?
No active medical treatment
- relieve symptoms
- prevent dehydration
What are the signs & symptoms of measles 7-14 days after exposure?
- high fever
- cough
- runny nose
- conjunctivitis
How does measles present clinically?
- begins with tiny white spots inside mouth (Koplik spots)
- rash begins on face & spreads downwards
What complications can arise from measles infection?
- pneumonia
- diarrhoea
- hearing loss
- brain swelling
- death (extreme)
How does measles spread?
RNA virus spreads via airborne transmission OR direct contact with infected respiratory secretions
What is the incubation period of mumps?
12-24 days
What are the symptoms of mumps?
- headache
- fever
- swelling of parotid gland
How is mumps transmitted?
direct contact with saliva/fomites or aerosol
What type of human papilloma virus is a risk factor for development of head & neck cancer?
HPV-16
What is aciclovir?
acrylic purine nucleoside
How does aciclovir work?
- viral enzymes add a phosphate group to aciclovir
- human enzymes add 2 more phosphate groups, producing aciclovir triphosphate
- during viral DNA replication, acicloir is added to growing strand rather than GTP & this halts viral replication
What is aciclovir used for?
Treatment of:
- herpes simplex (cold sores)
- zoster (shingles) infections
