Flashcards in Viral & Prion Proteins Deck (25):
What are herpes viruses?
Double stranded enveloped DNA viruses (herpes simplex 1 &2, varicella, Epstein Barr, CMV, Human Herpes 6A & B and 7 and 8.
- characterised by ability to establish latency and reactivate.
What do HSV-1 and HSV-2 cause?
HSV- 1 'cold sores' and 2 'genital herpes'.
via direct skin, genital or eye contact tw/ vesicle fluid from HSV lesions can cause..
1. ulcers (both)
2. encephalitis (HSV-1)
3. Meningitis (HSV-2)
4. Neonatal herpes - vertical transmission via mother's genital tract
What does herpes virus - Varicella Zoster Virus cause?
Primary infection - chicken pox, reactivation = herpes zoster/shingles
How does varicella virus spread?
Respiratory droplets of vesicle fluid from infected person, after primary infection latency established in dorsal root ganglion.
What is chicken pox?
febrile illness with widespread vesicular rash. Usually uncomplicated but sometimes can cause pneumonitis (esp adults), encephalitis, acute cerebellar ataxia
What are shingles/herpes zoster?
reactivation causing unialteral vesicles in a dermatomal dsitribution.
What is Epstein Barr/Glandular Fever/ Infectious Mononucleosis?
Virus spread by saliva and genital secretions. Causes - sore throat, fever, lymphadenopathy, hepatosplenomegaly.
Atypical lymphocytes in blood film - look like monocytes therefore mononucleosis.
What is cytomegalovirus?
CMV spread via saliva/gential secretions or donated organs. Causes infective mononucleosis primarily.
- Congenital infection = in mothers with virus babies can have retinitis, deafness, microcephaly.
- In immunosuppressed transplant patients
- In patients with HIV/AIDS reactivation of latent CMV can cause retinitis or colitis.
What is rhinovirus?
'common cold' - aerosolised respiratory secretions.
What is influenza?
Resp virus - can spread b/w species. A, B and C.
- Influenza A mutates regularly.
- viral surface proteins H & N have multiple variants.
What S and S in primary influenza illness?
fever, myalgia, headache, cough, nasal discharge, sore throat.
What S & S in Post-influenza secondary bacterial lung infection?
with S. pneumonia, H. influenzae, S. aureus.
What respiratory syncytial virus?
RSV occurs in winter, aerolised transmission of rest secretions.
- commonest in young children.
- can cause BRONCHIOLITIS in children under 2yrs. -> Inflammation of bronchioles cause cough, wheeze, hypoxia, fever.
When does AIDS results from HIV?
When virus load increases and T lymphocyte (CD4) cells fall. AIDS defining illnesses = TB, pneumocystis, pneumonia
How are hepatitis A and E spread and what are symptoms?
faeco-orally & nausea, myalgia, arthralgia, fevers, juandice, URQ pain
How are hepatitis B and C spread?
blood-borne. (Hep D = defective virus & can only survive with B).
What is the epidemiology of hepatitis A?
developing world (Europe), mostly children, lower socioeconomic groups
What is epidemiology of Hepatitis E?
Asia, Africa- associated with contaminated water. In developed countries w/ pigs & undercooked meat. Fulminant hepatitis in pregnant women.
How is Hep B transmitted?
vertically, sexually, parenterally. Most asymoptomatic but can become chronic and develop -> cirrhosis -> hepatocellular carcinoma.
How is Hep C transmitted?
IVDU, transfusion (sexually less common). 85% chrohic and then -> c -> hc c
What is Norwalk/norovirus?
ssRNA virus - common w/ short-lived immunity, esp. in point-source outbreaks e.g. hospitals.
- caused by ingestion/inhalation of vomit particles.
- vomiting dominant feature
What is Rotavirus?
dsRNA virus esp in childhood. Seasonal (winter).
- faced-orally spread, via contaminated food, aerosolised faeces.
- Symptoms = fever, vomiting and watery diarrhoea.
What are enteroviruses?
Polio, Coxsackie A and B, enterovirus and echovirus.
Epi = mostly in summer, most under 15Y
Spread & Path- faec-orally, don't cause GI symptoms -> LN -> viraemia
Syndromes to all = fever-rash in children, meningitis, encephalitis, severe disseminated diseases in neonate
Specific syndromes = Herpangina (mouth blisters) => Coxsackie A. Pericarditis => Coxsackie B.
What is parvovirus?
'slapped cheek syndrome'
- respiratory droplet transmission
- infects erythrocyte progenitor cells causing transient anaemia
Clinical Syndromes Associated:
1. Erythema Infectious = fever, fiery rash on cheeks.
2. Transient aplastic crisis = (affects those w/ high RBC turnover) e.g. sickle cell causes dyspnoea, confusion, cardiac failure,
3. Infection in pregnancy - fetal loss can occur, can develop hydrous fetalis - severe foetal anaemia, oedema, ascites, heart failure.