VHFs Flashcards
what is viral haemorrhagic fever
Group of viral infections whose presentation is characterised
by the presence of
* Fever
* Rash and
* Bleeding
outline the epidemiology of VHFs
VHFs viruses belong to 4 viral families
-All are enveloped, ssRNA
-Zoonotic viruses
* Humans are not the natural reservoir
* Animals or arthropod vector are reservoir
-Distribution is restricted to reservoir host
* Occasional spill-over do occur outside known natural
environment
-They have a similar mechanism of pathogenesis
Have a high morbidity & mortality
how is VHF transmitted?
Humans are accidentally infected
* Vector mosquito or tick bites a human
* During care for or slaughter the animals
e.g Rift valley fever
* When a human crushes an infected tick
with a hand or fingers e.g CCHF
* Contact with bodily fluid of an infected
rodent i.e urine, faecal material or saliva
e.g Lassa, Lujo
* Person-to-person transmission e.g
Ebola, Marburg, CCHF, Lassa
* Nosocomial transmission
what is the incubation period?
3-8 days in index cases & slightly longer in secondary cases
~21days
what are the signs and symptoms associated with VHFs?
Early: Non-specific Influenza-like illness (ILI) i.e fever, headache,
fatigue, dizziness, muscle aches
* Vomiting & diarrhoea are frequent, incl abdominal pain
severe illness?
- multi system syndrome multiple organ systems are affected
- Coagulation defects, vasodilation & increased vascular
permeability leads to - Conjunctival injection with petechial haemorrhage, bleeding
under the skin, in internal organs, or from body orifices - Oedema, hypotension and shock
what are the diagnostic tests?
- routine bloods: FBC, LFT
-specific testing: serogical, molecular and virus isolation
what is the treament of VHFs?
- VHF patients are managed under strict infection prevention
and control protocols - Isolation
- PPE
- Limited to experience & trained staff
-Treatment is mostly supportive (no specific treatment is not
available)
-Ribavirin is suggested for treatment of Bunya & Arena
viruses
-Treatment with convalescent-phase plasma has been used to
treat Ebola virus patients