viral and prion pathogens

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Describe the viral life cycle (8)
1) attachment 2) entry 3) uncoating 4-6) synthesis 7) assembly 8) release
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How are viruses classified?
1) genetic material- DNAvs RNA, single vs double stranded, positive vs negative sense 2) presence or absences of an envelope
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How many types of herpres viruses are known?
9 Types
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What is a characteristic of herpes?
Latency and reactivation
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What type of virus is herpes?
Double stranded envelope DNA virus
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Name the 9 herpes viruses
1) herpes simplex 1 2) herepes simplex 2 3)varicella zoster 4) epstein barr 5) cytomegalovirus 6) human herpes virus 6A 7)human herpes virus 6B 8) human herpes virus 7 9)human herpes virus 8
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What are the common names of HSV1/2?
HSV1= cold sores HSV2= genital herepes
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How is herpes simplex 1+2 transmitted?
Direct skin, genital or eye contact with vesicle fluid from HSV lesions Latency in sensory neurones
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What are the clinical symptoms of herpes simplex 1+2?
1) ulceration to skin/ mucous membrane 2) encephalitis 3) meningitis 4) neonatal herpes
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What is the common name for varicella zoster virus?
primary infection= chicken pox reactivation= herpes zoster/ shingles
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How is varicella zoster virus transmitted?
Respiratory droplet from person with primary infection Vesicle fluid from person with primary infection or reactivation Latency established in dorsal root ganglion
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Describe chicken pox symptoms
febrile illness with widespread vesicular rash Usually uncomplicated Complications include: pneumonitis (esp. adults), encephalitis, acute cerebellar ataxia
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Describe shingles/ herpes zoster presentation
Reactivation causing unilateral vesicles in a dermatomal distribution
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What is the common name for epstein barr virus?
Glandular fever’ or ‘infectious mononucleosis’ or ‘EBV
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How is epstein barr virus transmitted?
Virus is shed in saliva and genital secretions – ‘kissing disease’
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What are the clinical syndromes caused by epstein barr virus?
1) infectious mononucleosis (primary infection) 2) reactivation from latency in B cells
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What are the clinical features of infectious mononucleosis?
sore throat, fever, lymphadenopathy, hepatosplenomegaly atypical lymphocytes on blood film (looked like monocytes – ‘mononucleosis’) 80-90% of clinical infectious mononucleosis is EBV, rest is cytomegalovirus
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What are the features of epstein barr virus reactivation?
Especially if unwell or immunosuppressed Associated with post-transplant lymphoproliferative disorders
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How is cytomegalovirus transmitted?
Saliva or genital secretions Donated blood, stem cells or organs Latency in monocytes / dendritic cells / myeloid progenitors
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What clinical syndromes with cytomegalovirus?
1)infectious mononucleosis 2)congenital CMV infection 3)immunosuppressed transplant recipient 4)patient with advanced HIV/AIDS
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Describe the clinical syndrome of congenital CMV infection
In infants born to mothers who have primary infection during pregnancy Retinitis, deafness, microcephaly, hepatosplenomegaly in the neonate
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Describe the clinical syndrome of CMV in immunosuppressed transplant recipients
Either primary infection acquired from the transplanted organ / blood product Or reactivation as a result of immunosuppression (from latency in bone marrow)
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Describe the clinical syndrome of CMV in patients with advanced HIV/AIDS
Reactivation of latent CMV, causing retinitis or colitis
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What is rhinovirus also known as?
Common cold
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How is rhinovirus transmitted?
Aerosolised respiratory secretions and droplets from nose and eyes
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What are the clinical signs and symptoms of rhinovirus?
'Common cold’ – sneezing, nasal obstruction & discharge, sore throat, cough, headache and fever
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How is influenza transmitted?
Aerosolised respiratory secretions
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What are the 3 distinct types of influenza?
Influenza A. B. C
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What are the clinical syndromes of influenza?
1)Primary influenza illness: fever, myalgia (muscle aches), then headache, cough, sore throat, nasal discharge 2)Post-influenza secondary bacterial lung infection: with S.pneumoniae, H.influenzae, S.aureus
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How is respiratory syncytial virus transmitted?
Aerosolisation of respiratory secretions
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What an important clinical syndrome with respiratory syncytial virus?
Bronchiolitis: affects children under 2 yrs Inflammation of smallest airways – bronchioles Causes cough, wheeze, hypoxia and fever
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How is HIV transmitted?
Virus is present in blood, genital secretions, breast milk Transmitted vertically, sexually, needlestick
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What is the clinical course of HIV?
HIV targets helper T lymphocytes (CD4), 2-6 weeks after transmission, patients may develop an acute seroconversion illness Fever, sore throat, lymphadenopathy Asymptomatic chronic infection follows: steady state latest 1-15 years- AIDS increased load
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How is hepatitis spread?
Hep A+ E= faeco-oral Hep B+C+D= blood borne (vertical, sexual, parenteral)
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What is the epidemiology of hep A?
Infection of childhood, >90% children
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What is the epidemiology of hep E?
Peak incidence is young adults 15-35 years--> food such as uncooked meat
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What are the clinical features of hep A +E?
Nausea, myalgia, arthralgia and fevers then jaundice and right upper quadrant pain – self limiting
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Describe the clinical coarse of hepB
acute clinical hepatitis - asymptomatic of acute infection Hepatitis B is then cleared, or persists and becomes chronic Risk of chronicity is inversely related to age at infection
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Describe the course of hepB
acute clinical hepatitis--> chronic hepatitis--> cirrhosis--> hepatocellular carcinoma
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What type of virus is norovirus (norwalk)?
ssRNA virus
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What type f virus is rotavirus?
dsRNA virus (childhood virus)
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How is norovirus transmitted?
Ingestion / inhalation of aerosolised vomit particles
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How is rotavirus transmitted?
Faeco-oral, via contaminated food / water, and aerosolised faeces/vomit
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What are clinical differences between norovirus and rotavirus?
norovirus= vomiting dominant features rotavirus= fever, vomiting, watery diarrhoea
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List some serotypes of enteroviruses
Serotypes include poliovirus, Coxsackie A and B, enterovirus and echoviruses
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How is enteroviruses transmitted?
Enteric route: faeco-oral, contaminated food/water. Replicate in gut, but do NOT cause GI symptoms*** From gut → lymph nodes → blood (viraemia)
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What are the clinical features of enteroviruses?
Fever-rash syndromes in children, incl. hand foot and mouth ‘Common cold’ Meningitis (>50% viral meningitis cases are enteroviruses)*** Encephalitis Can cause severe disseminated disease in neonate
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What are 2 specific clinical syndromes of enteroviruses?
1)Herpangina – associated with Coxsackie A 2)Pericarditis – associated with Coxsackie B
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How is mumps transmitted?
Virus is shed in saliva and respiratory secretions Droplet transmission from respiratory route
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What clinical features/ syndromes do you see with mumps?
1) acute parotitis (unilateral/bilateral) 2) orchitis 3) meningitis
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How is measles transmitted?
Droplet transmission from respiratory route Highly infectious – environment still infectious after 2 hours***
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List important clinical syndromes of measles
1) primary measles-Fever,coryza,cough,conjunctivitis,Koplik’s spots on inside of cheek Then maculopapular rash 2)Acute post infectious measles encephalitis (7-10 days after acute infection) 3)Subacute sclerosing pan-encephalitis SSPE-7-10year after
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How is rubella transmitted?
Droplet transmission from respiratory route
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Describe the clinical syndrome in rubella
2)Primary postnatal rubella Mild illness, fever and maculopapular rash Arthralgia / arthritis occurs in 30% adults 1)Congenital rubella Classic triad: Bilateral cataracts, sensorineural deafness, microcephaly
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What is parvovirus B19 also known as?
‘Slapped cheek syndrome’ or ‘Fifth disease’
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How is parvovirus B19 transmitted?
Droplet transmission from respiratory route Infects and destroys erythrocyte progenitor cells – causing transient anaemia
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What are the clinical syndromes of parvovirus B19?
1)erythema infectiosum 2)transient aplastic crisis 3) infection in pregnancy
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What are the properties of human prion disease?
pathologic manifestations confined largely to CNS produce spongiform change in brain tissue on histology long incubation times (up to 30 yrs) progressive and fatal
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Card 2

Front

How are viruses classified?

Back

1) genetic material- DNAvs RNA, single vs double stranded, positive vs negative sense 2) presence or absences of an envelope

Card 3

Front

How many types of herpres viruses are known?

Back

Preview of the front of card 3

Card 4

Front

What is a characteristic of herpes?

Back

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Card 5

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What type of virus is herpes?

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