Virology Flashcards
Mpox - definition
Zoonotic orthopox virus with main animal reservoir being rodents
Clade II - West African - IIb the cause of outbreak MSM in 2022
Clade I - Central African
Mpox - transmission
Person to person through direct contact, respiratory secretions, low risk through touching clothing, mother to child during pregnancy
Mpox clinical symptoms
Day 1 - 5 Prodrome with fever, headache, fever
Macules to papulses to vesicles to pustules to scabs
Proctitis, pharyngitis, abscesses, pneumonia, encephalitis in severe cases (HIV CD4 <50)
Yellow fever - definition
Flavirvirus transmitted by aedes agypti mosquito endemic in South America and Africa. Howler monkey included in the life cycle (human is a dead end host)
Yellow fever clinical features
Asymptomatic
Fever, chills, headache, myalgia
Liver failure, encephalitis and DIC in severe cases
Yellow fever vaccination contraindications and considerations
Live attenuated vaccine and needs embryonated egg and cold chain
Avoid in immunocompromised
Elderly at greater risk of complications like viscerotropic disease and neurotropic disease
Hypersensitivity reactions (egg allergy as well)
Infants
1st degree relative with viscerotropic or neurotropic complications
Avoid in thymus disorder (MG, thymectomy)
Chikungunya definition and clinical syndrome
Alphavirus
Similar presentation to dengue
Vaccine available
Has been known to cause perinatal infections and encephalitis in neonates
Oropuche virus definition and clinical syndrome
Transmitted by midges
Often asymptomatic, with some reports of vertical transmission
Zika - definition
Flavivirus transmitted by aedes agypti/albopictus as well as sexual transmission and mother to child. No vaccination
Zika virus - clinical presentation
Incubation 3-12 days
Rash, fever, joint pain, conjunctivitis, headache, myalgia
Asymptomatic (80%)
Zika virus complications
- Congenital including microcephaly, developmental delay, epilepsy and eye complications (macular scarring, cataracts, glaucoma)
- Neurological GBS
Zika virus diagnostics
- PCR
- Blood and urine (urine lasts longer)
- Helpful in early infection or in detecting it in placental/umbilical cord blood - Serology
- Lots of cross-reactivity with other arboviruses
- Can be helpful to watch IgM seroconvert to IgG
HTLV1 definition
RNA retrovirus spread by cell to cell contact
HTLV1 geographical distribution
Japan, Latin America, Caribbean, Africa, Central Australia
HLTV1 transmission
Vertical, horizontal, blood contacts
HTLV1 - clinical presentation
95% asymptomatic
HTLV1 associated myelopathy (HAM) or tropical spastic paraparesis
Adult T cell lymphoma/leukaemia
Systemic complications of HTLV1
Infective dermatitis, strongyloides, autoimmune
HTLV1 - diagnostics
Serology EIA/Western blots, Provial PCR
Lassa fever - transmission, diagnosis, management
Arenaviridae virus
Associated with infected rodents but can have human to human transmission through contact with body fluids
Dx: ELISA for antigen detecttion
PCR
Mx: Ribavirin, supportive
Ebola - features, management, prevention
Filoviridae
Days 1-3 flu like illness
Days 4-7 GI and haemorrhagic symptkms
Days 7-10 severe phase with multi organ failure
Mx: supportive
Ring vaccination strategy with VSV live-attenuated vaccine
Sudan virus features, diagnosis, treatment
2-21 day incubation period
Flu-like illness –> vomiting and diarrhoea, rash and conjunctivitis
PCR + ELISA
Mx supportive and remdesivir, monoclonal antibodies have been registered in Uganda for compassionate use
Crimean-congo haemorrhagic fever summary
Tick bites or contact with infected animal tissue
Human to human transmission is rare
Symptoms usually 1-3 days after tick bite
Characterised by thrombocytopenia compared to other VHF
Yellow fever - type of virus
Flavivirus
Yellow fever - epidemiology
Africa + South America
Yellow fever - predictors of severe disease
Age >45 years
High viral load
AST >3500
Neutropenia
Hyperbilirubinaemia
Renal failure
Polio - cause
Poliovirus - entero RNA virus with 3 serotypes, serotype 1 being the most severe
Polio - transmission
Faecal-oral/pharyngeal
Polio - symptoms
Flaccid paralysis
Incubation 7-14 days
Polio vaccination strategies
IPV “killed” vaccine
OPV “live” vaccine
- Easy to administer as oral
- Greater enteric immunity
- Can transmit the vaccine between people
but
- Generally less seroconversion seen in the tropics
- Very small risk of paralysis (1 per million) which is why the killed vaccine is broadly used