Ebola virus disease (EVD)

introduction

the Ebola viruses are part of the family Filoviridae which also includes Marburg virus.
the likely natural host are fruit bats of the Pteropodidae family.
first emerged in the Democratic Republic of Congo and the Sudan in 1976.
it mainly occurs in rainforest areas of central Africa including Sudan, Congo, Uganda, Ivory Coast, Sierra Leone, Liberia, Guinea.
EVD is a severe, highly infectious disease of humans and primates which is fatal in ~90% of cases
outbreaks are usually contained within a few months, but social stigma and fear means many infected individuals do not seek medical help, if it is available, thereby spreading infection

Ebola outbreaks as at July 31, 2014, courtesy of Bloomberg

a suspected case of EVD is a case with clinical evidence AND epidemiological evidence

a history of fever ≥38°C in the last 24 hours OR subjective history of fever in the last 24 hours
WITH OR WITHOUT:
- additional symptoms such as severe headache, muscle pain, vomiting, diarrhoea, abdominal pain, unexplained haemorrhage.

within 21 days prior to onset of symptoms there was:
- residence in or travel to an area where EVD transmission is active OR
- one or more high risk exposures (see below) OR
- one or more low risk exposures (see below)

percutaneous or mucous membrane exposure to blood or body fluid of an EVD patient
direct skin contact with or exposure to blood or body fluids of an EVD patient without appropriate PPE
processing blood or body fluids of a confirmed EVD patient without appropriate PPE or standard biosafety precautions
direct contact with a dead body without appropriate PPE in a country where EVD transmission is active

household contact with a confirmed case of EVD;
persons who had direct contact with bats or primates in States with active EVD transmission;
other close contact with a confirmed case of EVD in health care facilities or community settings.
- close contact is defined as:
  - being within the same room of a patient with active vomiting or diarrhoea or coughing or the patient having an aerosol generating procedure, while not wearing appropriate personal protective equipment (i.e. as per standard, contact and droplet precautions);
  - having direct brief contact (e.g. shaking hands) with an EVD patient while not wearing appropriate personal protective equipment.

being in the near vicinity of a case with possible contact with a shared surface without appropriate PPE.

spread is via contact with secretions, blood or bodily fluids of infected wild animals, persons or corpses
includes contact with heavily contaminated fomites, sexual transmission, needles, and handling of raw or undercooked infected meat
burial ceremenonies are a known high risk activity for transmission
no documented cases of aerosol transmission

quarantine processes
standard contact and droplet precautions using gowns, gloves, face shields and masks
avoid high risk activities including sexual intercourse during infective period and eating wild animals
avoid aerosol-generating procedures unless adequate airborne precautions including negative pressure room, P2 masks, gowns, gloves are used.
in Victoria, suspected cases requiring ambulance transfer must have PRIOR notification to the Communicable Disease Prevention and Control Section of Department of Health on 1300 651 160 and ambulance personnel and receiving facilities must be made aware of the possible diagnosis

infected individuals are an infectious risk from onset of symptoms until at least 7 weeks after clinical recovery

viral haemorrhagic fever
incubation period with current strain is 4-6 days (but may be up 21 days)
sudden onset fever, muscle & joint aches
usually progresses rapidly to vomiting, diarrhoea, and sometimes haemorrhage from eyes, ears, mouth, and rectum with purpura and death

viral PCR or serology on blood samples - these require significant precautions see documentation ¹⁾
- in Victoria, must notify VIDRL first on (03) 8344 5689

¹⁾