Case Definitions

Suspected cases

Clinicians should be alert to the possibility of cases of VHF. Any previously healthy patient with sudden onset of Pyrexia of Unknown Origin (PUO) and pathognomic signs of facial oedema and haemorrhage should arise suspicion and be immediately reported to the local Consultant in Communicable Disease Control (CCDC).

In the event of a suspected deliberate release of VHF agents, a higher index of clinical suspicion should be maintained and the diagnosis considered if the symptoms outlined below present at medical services, especially if they arise in people who have been within or in close proximity to the exposed zone. Obviously the level of suspicion depends on clinical symptoms and the circumstances, but if a case is suspected, microbiological investigations are necessary to eliminate or confirm the diagnosis.

VHF syndrome can be described as an acute febrile illness characterised by malaise, prostration, generalised signs of increased vascular permeability and abnormalities of circulatory regulation. Bleeding manifestations often occur, especially in the more severely ill patients. Bleeding is a poor prognostic factor but death may not be due to a massive loss of blood volume.

Confirmed case

A case is a confirmed case if it clinically fits the criteria for VHF and is supported by laboratory investigations which include culture, PCR or specific serological testing.

Last reviewed: 11 May 2011