Virology Flashcards
What are the characteristics of a virus
Simple composition
No Intra cellular organelles
What is the structure of an enveloped virus?
Phospholipid envelope with spike proteins
Protein capsid and nucleic acid genome
What is an example of a DNA virus
Human herpes group
What is an example of RNA virus
Mumps virus
What are the principles of lab diagnosis
Provisional diagnosis
Confirmation of diagnosis after tests
How is a viral swab taken?
Using a flocked swab, place in molecular sample solution (MSS). After immersion, remove swab.
How is a blood sample obtained?
Using EDTA (purple top)
Use for serology and molecular detection of viral DNA/ RNA
Example of a pathogen present in erythematous/ maculopapular lesions?
Enterovirus
Example of pathogen present in vesicular lesions?
HSV1
Example of pathogens in ulcers?
HSV, enterovirus
What is responsible for primary antibody response?
IgM
What are the 5 main human herpes viruses?
Herpes simplex
Varicella
Zoster
Epstein Barr
HHV-8
What are the clinical features for Herpes simplex 1 and 2
Gingivo stomatitis
Bell’s palsy
What is the pathology of herpes simplex 1 and 2
Primary infection
Latency
Reactivation
Cold sores
What is the lab diagnosis for herpes simplex virus 1 and 2
Most can be made based on history and clinical appearance
Vesicle/ ulcer fluid- swab and molecular sample media for PCR
What is the clinical presentation of varicella?
Chicken pox
Can lead to secondary bacterial infections - pneumonia/ problems during pregnancy
What is the clinical presentation of zoster?
Shingles
Vesicles appear in dermatome representing cranial or spinal ganglia where the virus has been dormant
May be intensely painful/ parasthesia
What is the pathology of varicella
Primary infection- chicken pox
Latency in sensory ganglia
Recurrent infection- reactivation from sensory ganglia leading to shingles (when pt is immunosuppressed)
In which case is serum lab tests used for varicella- zoster?
Used for diagnosis of zoster for chicken pox exposure in HCWs
What is the prevention for shingles?
Zoster vaccine for over 70 yrs
What microorganism is responsible for hand for and mouth disease? And what are the clinical presentations?
Enterovirus infection
Symptoms = fever, runny nose, sneezing, cough
Skin rash, mouth blisters, body and muscles ache
What is the prevention and management of hand foot and mouth disease?
No medical treatment
Relief of symptoms and prevent dehydration
What is measles?
RNA virus, spread by direct contact with saliva/ aerosol
Highly infectious
Kopliks spots- white spots occur in oral epithelium (looks like salt grains)
What is the lab diagnosis for measles?
Oral swab for RNA detection
What is papilloma virus?
HPV 16 risk factor for head and neck squamous cell carcinoma
What is monkey pox?
Enveloped DNA virus
Transmitted through close contact with person/ animal
Self limited disease
Rash developing into blisters on skin/ face/ genitals
What is the lab diagnosis for monkey pox?
PCR for viral DNA from swabs
What is aciclovir?
Anti viral drug
Used to treat Intra oral and peri oral viral infections - herpes simplex (esp reactivation- cold sores) and zoster (shingles)
What type of drug is aciclovir?
An acyclic purine nucleoside
What is the action of acyclovir?
Tricks replicating herpes virus into incorporating defective molecule into growing DNA chain, inhibiting DNA polymerisation (synthesis)
In which type of cells is acyclovir active in?
Infected cells
Why is acyclovir not effective against viruses in latency period?
Acyclovir targets active replication (which these viruses are not doing)
