Oral Viral Infections

Question 1

What are the general characteristics of a virus?

Answer 1

 Small- much smaller than bacteria/human cells
 Simple chemical composition- proteins, phospholipids, glycoproteins, nucleic acids (changes depending on family)
 No intracellular organelles- obligate intracellular parasites
 DNA/RNA- can have either

Question 2

What are examples of DNA/RNA viruses?

Answer 2

DNA virus- human herpes

RNA virus- mumps

Question 3

What are the stages of replication of Herpes Simplex?

Answer 3

1. Binding
2. Entry into cytoplasm
3. Release and nuclear transport
4. Nuclear entry
5. Gene expression- ribosomes translate viral genes into proteins
6. DNA replication via viral DNA polymerase
7. Packaging
8. Egress via endoplasmic reticulum, golgi apparatus and plamsma membrane

Question 4

What does 1/2 triangles mean?

Answer 4

1- Diagnosis
2- Provisional diagnosis

Question 5

How is a viral sample taken?

Answer 5

Use viral swab- flocked

Place in molecular sample solution- extracts viral DNA/RNA

After immersion- remove swab

Question 6

What is used when taking a blood sample to check for viruses?

Answer 6

EDTA- purple topped
-> used in serology and molecular detection of viral DNA/RNA

Question 7

What information should be included in virology request form?

Answer 7

Pt details & clinician details (inc phone no.)

Clinical details & diagnosis

Date of onset

Patient DOB or CHI number

Specify test (do not request “viral screen”)

Question 8

What is a maculo-papular rash?

Answer 8

Red flat area on the skin covered with bumps (macules/Papules)

Question 9

Which viruses can cause a macula-papular rash?

Answer 9

Enterovirus

HHV6

HHV7

Measles

Rubella

*B19, CMV, EBV- require serology for detection using EDTA blood sample

Question 10

What is a vesicle?

Answer 10

Fluid filled blister

Question 11

Which viruses are associated with vesicular lesions?

Answer 11

HSV1

HSV2

VZV

Enterovirus

Question 12

What is an ulcer?

Answer 12

break in bodily membrane

Question 13

Which viruses are associated with causing ulcers?

Answer 13

HSV

Enterovirus

Question 14

What specimen/test is required for detecting the cause of macula-papular rashes, vesicular lesions and ulcers?

Answer 14

Specimen- mouth swab

Test- RNA/DNA detection

Question 15

What is serology used for?

Answer 15

Detect presence of antibodies against a virus?

Question 16

Which viruses can be diagnosed from presence of IgM antibodies?

Answer 16

CMV

EB

Question 17

Which viruses can be diagnosed from presence of IgG antibodies?

Answer 17

HSV/Varicella Zoster

Question 18

Was is meant by laboratory stewardship?

Answer 18

Only using lab as a resource when required
-> Most diagnoses are made via history/clinical investigation

Question 19

What is characteristic about the appearance of herpes viruses?

Answer 19

Look like a fried egg

Question 20

What are the types of herpes virus?

Answer 20

Herpes simplex type 1
Herpes simplex type 2
Varicella zoster- chicken pox/shingles
Epstein Barr
Cytomegalovirus
HHV-6
HHV-7
HHV-8 (Kaposi’s Sarcoma Associated virus)

Question 21

What are the common features of infections with HHVs?

Answer 21

Primary infection

Latency

Recurrent infection

Question 22

What conditions can HSV1/2 cause?

Answer 22

Gingivo-stomatitis
Herpes labialis- cold sores
Keratoconjuctivitis
Herpetic whitlow
Bell’s palsy
Genital herpes

Question 23

What are the steps in the pathogenesis of HSV?

Answer 23

Acute infection

Latency

Reactivation

-> Cold sores, viral shedding, cell death

Question 24

What is the reservoir for HSV?

Answer 24

Saliva

Question 25

What is the route of transmission for HSV?

Answer 25

Direct by close person to person contact

Question 26

When does atypical reactivation of HSV occur? What can be used to diagnose this?

Answer 26

In immunocompromised patients -> take viral swab and do PCR

Question 27

What is used to treat HSV infections?

Answer 27

ACV to prevent recurrent infection in difficult cases (200mg x5 daily ACV) Topical therapy with ACV (aciclovir cream 5%) IV therapy for severe & immunosuppressed

Question 28

What is the incubation period for Varicella-zoster?

Answer 28

10-21 days

Question 29

What are the potential complications of a Varicella infection?

Answer 29

Secondary bacterial infections- group A strep can colonise skin lesions Pneumonia- vesicles form on epithelial lined surface of lung Congenital, perinatal/neonatal issues

Question 30

What are the signs and symptoms of zoster infection?

Answer 30

Vesicles appear in dermatome of cranial or spinal ganglia where the virus has been dormant -> The affected area may be intensely painful with associated paraesthesia

Question 31

What are the potential complications of zoster?

Answer 31

Post herpetic neuralgia Secondary bacterial infections Ophthalmic zoster Ramsay Hunt syndrome- paralysis of facial nerve

Question 32

What are the stages in the pathogenesis of varicella zoster virus?

Answer 32

Primary Infection: Infection with varicella zoster virus Latency: Sensory ganglion (Trigeminal) Recurrent Infection: Reactivation of latent virus from sensory ganglion (associated with immunosuppression due to age/tx)

Question 33

What is the route of transmission for Varicella-Zoster?

Answer 33

Direct contact, droplet or airborne spread

Question 34

In what groups is occurrence of Varicella and Zoster most common in?

Answer 34

V- Children Z- Immunosuppressed/older

Question 35

What can be used to test for Varicella-Zoster in atypical cases?

Answer 35

Swab of vesicular/ulcer fluid in MSM -> PCR Serum IgG test (not used for diagnosis of zoster) – usually used for chickenpox exposure in HCW’s

Question 36

How is varicella infection prevented?

Answer 36

Chicken pox vaccine (not routine)- only given to patients who are vulnerable to chickenpox/complications

Question 37

How is shingles (zoster) treated?

Answer 37

Aciclovir: 800mg Oral x5 daily for 7 days -> Refer all patients with herpes zoster to a specialist or their general medical practitioner.

Question 38

What is used to prevent zoster infection?

Answer 38

Zostavax- Live attenuated virus -> Schedule: All people aged 70 + years

Question 39

What are the symptoms of an enterovirus infection? (hand, foot and mouth diseases)

Answer 39

Fever, runny nose, sneezing, cough, skin rash, mouth blisters, and body/muscle aches

Question 40

What are examples of enteroviruses?

Answer 40

Coxsackie- dentally relevant Polio

Question 41

How does enterovirus infection spread?

Answer 41

Nose and throat secretions Fluid from blisters or scabs Faeces

Question 42

When are enteroviruses at their most infective?

Answer 42

First week

Question 43

Which populations tend to suffer from enterovirus infections?

Answer 43

Common in under 5s- nursery/school outbreaks -> can happen to anyone

Question 44

What can be used to diagnose enterovirus infection?

Answer 44

Oral swab for detection of enterovirus RNA -> not usually required

Question 45

How is hand, foot and mouth disease prevented/treated?

Answer 45

P= Hand washing Tx= Relieve symptoms and treat dehydration

Question 46

What are the signs and symptoms of measles?

Answer 46

7-14 days after infection- high fever, runny nose, conjunctivitis, Cough 2-3 days later- Appearance of Koplik spots in the mouth (breakdown of epithelium) 3-5 days later- rash appears on face and spreads downwards

Question 47

What are the potential complications of measles?

Answer 47

Pneumonia Brain swelling Hearing loss Diarrhoea Death -> MMR vaccine reduces risk

Question 48

How is Measles transmitted?

Answer 48

RNA virus is spread through airborne transmission or direct contact with infected respiratory secretions

Question 49

What is mumps?

Answer 49

Epidemic parotitis

Question 50

How long is the incubation period for mumps?

Answer 50

12-24 days -> asymptomatic carriage possible

Question 51

What are the symptoms of mumps?

Answer 51

headache fever swelling of the parotid glands (uni or bilateral)

Question 52

What other conditions can develop as a result of mumps infection?

Answer 52

deafness, encephalitis, pancreatitis, neuritis, arthritis, mastitis, nephritis, thyroiditis, ovaries (oophoritis), swelling of the testes (orchitis) and pericarditis.

Question 53

What type of virus is mumps?

Answer 53

Paramyxovirus family - RNA

Question 54

How is mumps spread?

Answer 54

Transmission is by direct contact with saliva/fomites or aerosol

Question 55

How is mumps diagnosed?

Answer 55

Oral fluid IgM antibody tests or PCR

Question 56

How are measles and mumps prevented?

Answer 56

MMR vaccine- routine childhood immunisation

Question 57

What is HPV16 a risk factor for?

Answer 57

Head and neck squamous cell carcinoma

Question 58

What is aciclovir?

Answer 58

Acyclic purine nucleoside -> commonly used for intra-oral and perioral viral infection

Question 59

How does aciclovir work?

Answer 59

 Tricks replicating herpes virus into incorporating DOG molecule (defective) into growing DNA chain, blocking further synthesis of viral DNA  Inhibits DNA polymerase (preferential termination- only viral not host DNA)

Question 60

What is aciclovir's target viral molecule?

Answer 60

Viral enzyme- thymidine kinase -> Higher affinity for acyclovir (only active in infected cells) -> Mutations in this viral can cause resistance as it avoids action of drug

Question 61

What stage of infection does aciclovir work on?

Answer 61

Active replication stage -> latency phase is not affected

Question 62

What is aciclovir used to treat in a dental setting?

Answer 62

Various intra-oral/peri-oral viral infections -> Herpes simplex (cold sores) and Zoster (shingles) infections

Question 63

How can aciclovir be administered?

Answer 63

Topically Systemically -> orally or intravenously

Question 64

What is the pro-drug for aciclovir and peniciclovir?

Answer 64

A- valacyclovir P- Famciclovir