VHFs

Question 1

what is viral haemorrhagic fever

Answer 1

Group of viral infections whose presentation is characterised
by the presence of
* Fever
* Rash and
* Bleeding

Question 2

outline the epidemiology of VHFs

Answer 2

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

Question 3

how is VHF transmitted?

Answer 3

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

Question 4

what is the incubation period?

Answer 4

3-8 days in index cases & slightly longer in secondary cases
~21days

Question 5

what are the signs and symptoms associated with VHFs?

Answer 5

Early: Non-specific Influenza-like illness (ILI) i.e fever, headache,
fatigue, dizziness, muscle aches
* Vomiting & diarrhoea are frequent, incl abdominal pain

Question 6

severe illness?

Answer 6

• 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

Question 7

what are the diagnostic tests?

Answer 7

• routine bloods: FBC, LFT
  -specific testing: serogical, molecular and virus isolation

Question 8

what is the treament of VHFs?

Answer 8

• 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