Viral infections in dentistry Flashcards
List the general features of a virus
- RNA or DNA; double- or single-stranded
- Enveloped or non-enveloped (nucleocapsid)
- Symmetry of capsid & its dimension
List the viruses that are normally found in the oral cavity
- Hepatitis A, B & C viruses
- HIV-1 & 2
- Others eg. influenza virus, respiratory syncytial virus, etc
List the 4 viruses that cause oral pathology
- Coxsackie A viruses
- Herpes family virus
- Human papilloma viruses (HPV)
- Others eg. Mumps virus, measles virus
Describe the characteristics of coxsackie viruses, and list the two types of coxsackie A viruses
Characteristics:
• Groups of small, non-enveloped, ss(+) RNA viruses
Two types:
• Herpangina
• Hand foot and mouth disease
Describe herpangina in terms of:
- Incubation period
- Symptoms (4)
- Clinical oral signs (appearance and place of occurrence)
Incubation period:
• 3-5 days
Symptoms: • Sore throat • Difficulty when swallowing • Mild fever • Malaise
Clinical oral signs:
• Small vesicular lesions with a white base
• Present on the posterior soft palate near the uvula & anterior fauces of the tonsils
Describe hand, foot and mouth disease in terms of:
- Incubation and which group are most affected
- Transmission route
- Symptoms (3)
- General clinical signs
- Clinical oral signs (location)
Incubation and which group are most affected:
· 3-5 days
· Mostly in children 1-5 years old
Transmission route:
· Faecal-oral or pharyngeal secretions.
Symptoms:
· Malaise
· Low grade fever
· Nausea
General clinical signs:
· Eruption of small vesicles with an erythematous base on the palms of the hands & the feet
Clinical oral signs:
· Oral lesions emerge 1-2 days later, usually confined to the anterior part of the mouth
Describe the features of herpes viruses, mention how they acquire their membrane
· Large, enveloped, linear dsDNA viruses. 8 different families.
· Acquire their lipid envelope with glycoproteins from host cells
Briefly explain the first four types of herpes family viruses in terms of where their LATENT sites are
HSV 1:
• Herpes simplex 1:
• Can be primary or secondary
• Principal latent site is the neuron
HSV 2:
• Herpes simplex 2
• Occurs primarily in the genitals
• Principal latent site is the neuron
HSV 3:
• Varicella zoster viruses
• Principal latent site is the neuron
HSV 4:
• Epstein- Barr virus
• Principal latent site are B- cells
Explain primary herpes simplex-1 infection aka herpetic gingivostomatitis by stating:
- Who is most affected
- Clinical oral signs
- Symptoms (3)
Who is most affected:
· Occurs in most people by 15 yrs old
Clinical oral signs:
· Multiple shallow ulcers scattered throughout the keratinized intraoral surfaces
· Mild-severe
· Resolve in 10 days
Symptoms: · Uncommon · Lymphadenopathy · Fever · Myalgia.
Explain primary herpes simplex-1 infection aka herpetic gingivostomatitis by stating:
- Its histological features
Histological features:
· Epithelium shows ballooning degeneration (swelling of without vacuolization, enlarged or condensed nuclei)
· Multinucleated epithelial giant cells
For RECURRENT HSV-1 infections, explain:
- Where the virus survives in its latent form
- What causes recurrent HSV-1 infection
- Clinical presentations (4)
- Associated complications (3)
Where the virus survives in its latent form:
· Sensory nerve ganglion
What causes recurrent HSV-1 infection:
· Occurs when the virus doesn’t completely clear
· The virus survives in sensory nerve ganglion in a latent form
· Virus re-emerges from infected nerve to infect overlying epithelium
Clinical presentations: · Herpes labialis (cold sores) · Intraoral ulcers · Herpetic whitlow · Ocular herpes
Associated complications:
· Neonatal herpes
· Meningitis
· Ocular herpes
For HSV-1 infections, list:
- Triggering factors
Triggering factors · Sunlight · UV · Wind · Fever · Injury · Surgery · Menstruation · Stress
Explain HSV-2 infections in terms of where they occur, and their oral significance
- Occur primarily in the genital regions, but oral infections are becoming more common
- Associated with increased risk of cervical cancer and oral cancers if present in the mouth
Explain varicella zoster (chicken pox) in terms of:
- Where the virus survives in its latent form
- Incubation
- How the virus works
- Reactivation
Where the virus survives in its latent form:
· Spinal ganglion
Incubation:
· 2-3 wks incubation
How the virus works:
· Virus replicates in regional lymph nodes of throat, then liver and spleen
· Then it spreads to skin & mucous membranes
Reactivation:
· Known as herpes zoster (shingles)
· The lesions follow a unilateral distribution
Explain varicella zoster (chicken pox) in terms of:
- General clinical signs, including presentation in older patients
- Clinical oral signs
General clinical signs, including presentation in older patients:
· Pain, paraesthesia, & dysesthesia
· Prodromal: pain on both skin & mucous membrane few days before vesicle eruption
· In older patients, the pain may persist for a month or more as post-herpetic neuralgia (due to nerve damage)
Clinical oral signs:
· Vesicles rupture early
· Seen as small ulcers resembling aphthous ulceration
Explain the Epstein- Barr Virus (EBV) in terms of:
- Where the virus survives in its latent form
- Incubation
- How the virus works/ why detection is hard
Where the virus survives in its latent form:
· B lymphocytes (CD21) & epithelial cells
Incubation:
• 4-6 weeks
Why detection is hard:
• EBV remains latent in B cells and periodically, the virus can reactivate asymptomatically to emerge in the saliva, hence, impossible to detect and stop transmission
• Higher prevalence in periodontal & periapical lesions.
Explain the Epstein- Barr Virus (EBV) in terms of:
- General clinical signs in children and adults
- The diseases it may cause (4)
General clinical signs:
• In children: primary is very mild or subclinical
• In adults: symptoms of infectious mononucleosis (fever, sore throat, and swollen lymph glands that resolves in 1-2 mths)
The diseases it may cause: • Infectious mononucleosis • Burkitt’s lymphoma (B cell lymphoma) • Oral hairy leukoplakia • Nasopharyngeal carcinoma esp. in East Asians & Africans
Discuss the human papilloma virus (HPV) in terms of:
- Virus characteristics
- Where the virus survives in its latent form
- The three types seen clinically
- Their association with pathology
- Their effect on the oral cavity
Virus characteristics:
· Mid-sized, non-enveloped, dsDNA viruses
· Over 100 types, ranging from natural viral skin flora to those causing warts to genital cancers
Where the virus survives in its latent form:
· Basal epithelial cell DNA
The three types seen clinically:
· Verruca vulgaris/ common skin warts
· Papilloma
· Condyloma acuminatum/ genital warts: some are associated with cervical cancer (vaccine available)
Their association with pathology:
· Majority of oral cancers (SCC) are HPV-positive
Their effect on the oral cavity:
· HPV-13 & 32 seems to be restricted to oral cavity to cause focal epithelial hyperplasia (Heck’s disease) but not too dangerous
Explain mumps and measles viruses by stating:
- Virus characteristics
- Incubation
- Clinical signs and symptoms of mumps (4)
Virus characteristics:
· Large, spherical, enveloped, ss(-)RNA viruses
· Can be fatal in immunosuppressed patients
· Rare due to MMR vaccine.
Incubation
· 2-3 weeks
Clinical signs and symptoms of mumps · Swelling of the salivary glands (esp. parotids) · Orchitis · Pancreatitis · Skin rash may occur
Explain mumps and measles viruses by stating:
- Clinical signs and symptoms of measles (4)
Clinical signs and symptoms of measles · 4-day fever · Cough · Coryza (head cold) · Conjunctivitis
