Viral haemorrhagic fevers (including Ebola disease)

Viral haemorrhagic fevers are a group of serious and often fatal diseases caused by several families of viruses. These include:

• Ebola disease, which is caused by several ebolaviruses, including Ebola (Zaire) virus, Sudan virus and Bundibugyo virus
• Marburg virus disease
• Lassa fever
• Crimean-Congo haemorrhagic fever.

The viruses that cause viral haemorrhagic fevers are not found in Australia. These diseases are reported in different parts of the world including Africa, the Middle East, Asia and Eastern Europe. Cases have occasionally been reported internationally in travellers who have returned from areas where the diseases occur.

The largest recorded viral haemorrhagic fever outbreak occurred in West Africa from 2014 to 2016 and was caused by Ebola (Zaire) virus, resulting in more than 28,600 cases and 11,300 deaths.

Viral haemorrhagic fevers are caused by viruses that can be carried by animals or spread by ticks. For Ebola disease and Marburg virus disease, bats are thought to be the natural animal host and may pass the virus to other animals.

Depending on the virus, people may first become infected through contact with infected animals, animal tissues or bodily fluids. Crimean-Congo haemorrhagic fever infection is also spread by tick bites.

Once a person is infected, viral haemorrhagic fever can spread from person to person. This usually occurs when blood or bodily fluids from a person who is unwell with, or has died from, a viral haemorrhagic fever come into contact with another person’s eyes, nose or mouth. A person may also become infected when infectious blood or bodily fluids come into contact with broken skin (such as a cut or sore). Potentially infectious bodily fluids include blood, vomit, faeces, urine, saliva and semen.

Spread can also occur through contact with contaminated surfaces or items used by a person with viral haemorrhagic fever, such as bedding, clothing or medical equipment.

People are not infectious until they develop symptoms.

Depending on the viral haemorrhagic fever, symptoms usually begin between 2 and 21 days after exposure to the virus. For Ebola disease, symptoms commonly begin after 8 to 10 days. Early symptoms may be difficult to distinguish from common infectious diseases in areas affected by viral haemorrhagic fever outbreaks, including malaria, dengue, typhoid fever, yellow fever and shigellosis.

Early symptoms can be flu-like and may include:

• fever
• severe headache
• tiredness or weakness
• muscle and joint aches
• sore throat.

As illness progresses, symptoms may include:

• abdominal pain
• vomiting
• diarrhoea
• rash or unexplained bruising
• bleeding, which may be internal or external
• confusion, reduced consciousness or other signs of severe illness.

Most travellers to areas affected by viral haemorrhagic fever outbreaks are at very low risk. People may be at higher risk if they have recently returned from an affected area and have had a possible exposure to the virus. These people include:

• healthcare workers, aid workers and others who cared for a person with viral haemorrhagic fever without appropriate personal protective equipment (PPE), or where PPE was damaged or used incorrectly.
• other travellers who may have been exposed through direct contact with people who were unwell, their bodily fluids, infected animals or animal tissues, or by taking part in burial or funeral practices.

A licenced vaccine is available in some countries to protect against Ebola (Zaire) virus. It has not been shown to protect against other ebolaviruses, such as Sudan virus or Bundibugyo virus. The vaccine does not provide protection against other viral haemorrhagic fevers. The vaccine is recommended only for use in outbreak settings and is not available in Australia.

The best way to prevent infection is to avoid direct contact with people or animals who may be infected, including the body of a person who has died from a viral haemorrhagic fever. In affected areas, avoid hunting, handling or eating wild animals (sometimes called ‘bushmeat’).

Viral haemorrhagic fevers are diagnosed using specialist laboratory testing, usually on a blood sample. Testing is only recommended when a person’s symptoms and travel or exposure history suggest they may be at risk. Public health officials and specialist clinicians coordinate this assessment. Testing is performed at designated laboratories with appropriate biosafety measures.

If you have symptoms

If you have symptoms and have recently travelled to an affected area, or had contact with a confirmed case of viral haemorrhagic fever, call ahead before attending a GP clinic or emergency department so precautions can be put in place before you arrive.

For Ebola disease caused by Ebola (Zaire) virus, the World Health Organization recommends 2 treatments: Ebanga^TM and Inmazeb^TM. There are currently no approved treatments for other viral haemorrhagic fevers, including Ebola disease caused by other ebolaviruses such as Sudan virus and Bundibugyo virus. These treatments are not available in Australia.

Early diagnosis and supportive care can be lifesaving. Treatment may include intravenous fluids and monitoring and management of complications. In WA, people with suspected or confirmed viral haemorrhagic fever are cared for in designated hospitals with appropriate isolation and infection control measures.