Principles of Infection II Flashcards
What is the cell structure of the herpes simplex virus?
- virus has an envelope
- 120 to 300 nm
- nucleocapsid inside evenloped structure
- tegument between nucleocapsid + envelope
- virus has DNA
What is the name of the family of DNA viruses responsible for herpes infections?
Herpesviridae
How is herpes simplex virus type 1 transmitted?
Contact transmittion - from person to person, by sharing objects or even oral sex.
How is herpes simplex virus type 2 transmitted?
Transmitted by skin contact - usually sexually transmitted
What does more sexual partners suggest?
More likely to have antibodies to HSV2, but having a single sexual partner doesn’t mean you will not be infected.
When infected, do you ever clear the virus - what happens?
No, you have periods of latency - virus replication stops and then reactivation - release of latent virus.
What is the common figure for reccurences of the herpes virus?
1-5 per annum, some never have them, some have them frequently
Which virus causes chickenpox?
Varicella Zoster virus
Which virus causes glandular fever and how is it transmitted?
Epstein Barr virus - transmitted via saliva (kissing disease!)
What is the cellular structure of adenovirus, it’s transmission and impact?
- no envelope - dna virus
- transmitted via contact
- has different ‘serotypes’ -> causes eye/resp/GI infection
What is the cellular structure of papillomavirus, it’s transmission and impact?
- no envelope - DNA genome
- horizontal (human to human) - sex involved
- causes warts + cervical cancer
What is the structure of HIV?
- enveloped
- RNA virus
What is the structure of rotavirus and its cause?
- non enveloped
- small
- causes diarrhoea
Which viruses are transmitted horizontally (human to human)?
- measles
- mumps
- adenovirus
- influenza
- ebola
What are some early symptoms of ebola infection?
- take 2-21 days to show
- fever
- headache
- diarrhoea
- vomiting, stomach/muscle pain
- unexplained bleeding + bruising
What is the structure of ebola virus?
- RNA virus
- enveloped
What is the pathophysiology of ebola (how it enters/impacts) and how is it transmitted?
- enters through mucuous membranes, breaks in skin, parenterally
- infects many cell types
- migrates from initial site to lymph nodes -> liver, spleen, adrenal
- tissue necrosis + organ failure
- inflammation
- transmitted by direct contact with body fluids + contaminated objects (person to person)
How is rubella transmitted?
vertical (mother to foetus) mainly
Which diseases can be transmitted by insect bites and animal bites?
Insect bites: haemorrhagic fevers, yellow fever
animal bites: rabies
What are some clinical factors of diagnosing infection?
- patient symptoms
- duration of symptoms
- have there been contacts with sources of infection
- what is circulating in the population
- location
- lifestyle
- other risk factors
What antibodies are looked for in an immunoassay?
IgM - recent infection
IgG - past infection
Describe the method of culturing virus in cells
Human viruses need human cells to grow - takes 2-3 days, use light microscopy for cytopathic effect.
What is a quicker alternative with culturing virus in cells?
Look for viral proteins in cell cultures:
- use immunofluorescence labelling method
- use antibody directed against viral proteins
- label antibody with immunofluorescence tag
- you can see viral proteins
Describe the method of looking for RNA/DNA in the blood and how it can be amplified
- difficult to detect RNA/DNA as not enough in sample
- use PCR to amplify nucleic acid
- run it on a gel and see amplified product as a band
