Oral Viral Infections Flashcards
What are the characteristics of a virus
- small size
- simple chemical composition
- no intracellular organelles
Describe the structures present in a typical enveloped virus
- phospholipid envelope
- nucleic acid genome
- protein capsid
- spike projections
How is genetic information stored in viruses
as DNA or RNA
Describe the stages of herpes virus replication
- binding
- entry
- release and nuclear transport
- nuclear entry
- gene expression
- DNA replication
- packaging
- egress
What type of virus is herpes simplex
DNA
How can viruses be diagnosed
viral swab
blood sample (EDTA)
What type of swab should be used for a viral swab
flocked
What should the flocked swab be placed in
molecular sample solution
What is required to complete a virology request form
- patient details
- clinician details
- clinical details and prov diagnosis
- date of onset
- patient DOB/chi
- specify test
What is required to complete a virology request form
- patient details
- clinician details
- clinical details and prov diagnosis
- date of onset
- patient DOB/chi
- specify test
What are the common pathogens that cause a maculopapular rash
- enterovirus
- HHV6
- HHV7
- measles
- rubella
What are the common pathogens that cause a vesicular rash
- HSV1
- HSV2
- VZV
- enterovirus
When using a mouth swab, how is viral nucleic acid detected
nucleic acid amplification
How do blood tests diagnose
nucleic acid amplification
or antibody levels
Which antibody response do we look for for HSV
IgG
What are the 3 stages of human herpes virus
- primary infection
- latency
- recurrent infeciton
What are the clinical features of type 1 and 2 HSV
gingivostomatitis
herpes labialis
keratoconjunctivitis
herpetic whitlow
bells palsy
genital herpes
What can treatment for HSV be split into
- chemoprophylaxis
- antiviral therapy
What is chemoprophylaxis dosage (prevention of disease)
ACV to prevent recurrent infection in difficult cases
200mg x 5 daily ACV
What is the antiviral therapy tx
- topical therapy with ACV
- 5%
- IV therapy for severe and immunosuppressed
What is the incubation period of varicella (chicken pox)
10-21 days
What are the complications of varicella (chicken pox)
secondary bacterial infections (group a strep)
pneumonia
congenital, perinatal/neonetal
What are the clinical features of zoster (shingles)
- vesicles appear in dermatome, representing cranial or spinal ganglia where the virus has been dormant
- the affected area may be intensely painful with associated paraesthesia
What are the complications of shingles
- post herpetic neuralgia
- secondary bacterial infections
- opthalmic zoster
- ramsay hunt syndrome
Describe the pathogenesis of varicella zoster
- primary infection = infection with VZ virus
- latency = sensory ganglion (trigeminal)
- recurrent infection = reactivation of latent virus from sensory ganglion
What is the route of transmission of VZ
- durect contact, droplet or airborne spread
What is the lab diagnosis for VZ if wanted
- PCR
- not serum unless for HCW
Why is VZ relevant to dentistry
can mimic severe toothache
antiviral therapy is 800mg oral x 5 days for 7 days
What are the different herpes viruses
herpes simplex
varicella zoster
epstein barr
cytomegalovirus
HHV 8
HHV 6 & 7
What is enterovirus infection the cause of
hand foot and mouth disease
What are the symptoms of hand food and mouth disease
fever
runny nose
sneezing
cough
skin rash, mouth blisters and body ache
** macular rash
What is the dentally relevant enterovirus
coxsackie – causes HFM
What lab test can be used for HFM disease if uncertain diagnosis
oral swab for detection of enterovirus RNA
What is the pathogenesis of measles
a rna virus spread through airbone transmission or direct contact with infected resp secretions
What is the lab diagnosis of measles made from
mouth swab
PCR
What virus causes mumps
paramyxovirus
RNA
What is the incubation period of mumps
12-24 days
What are the symptoms of mumps
- headache and fever
- swelling of parotid glands
What is aciclovir
an acyclic purine nucleoside
How does aciclovir work
inhibits dna polymerase
it tricks the herpes virus into incorporating the defective molecules into the DNA chain and so it blocks further synthesis
the aciclovir is missing an OH group
Describe in detail the mechanism of aciclovir
- viral enzyomes add to phosphate group to acyclovir
- human enzymes add two more phosphate groups, producing acyclovir triphosphate
- during replication, acyclovir is added to the growing strand rather than GTP and this halts furhter elongation of the DNA molecule and stops viral replication
What is aciclovir used for in dentistry
managing HSV (cold sores) and zoster (shingles)
resistance can occur via mutation in viral thymidine kinase
