What are Viral haemorrhagic fevers?
Viral haemorrhagic fevers (VHFs) are a group of serious and potentially life-threatening illnesses caused by several distinct families of viruses. Examples include Ebola virus disease, Marburg virus disease, Lassa fever, and Crimean-Congo haemorrhagic fever. While locally acquired infections do not occur in Australia, these diseases are seen in different parts of the world, predominantly during outbreaks in Africa, but also sporadically in the Middle East, Asia, and Eastern Europe.
The viruses that cause viral haemorrhagic fevers (VHFs) are naturally carried by animals, with each virus having its own animal reservoir and mode of transmission. Lassa fever is spread by the multimammate rat, with people becoming infected through contact with food, household items, or surfaces contaminated by rodent urine or faeces. Person-to-person transmission can also occur through contact with bodily fluids of someone with the disease. Crimean-Congo haemorrhagic fever is usually transmitted through the bite of an infected Hyalomma tick or by contact with the blood or tissues of infected livestock during slaughter. Ebola and Marburg viruses are thought to be carried by fruit bats, with infection occurring through contact with infected wildlife, followed by person-to-person spread through direct contact with blood or other bodily fluids, or contaminated medical equipment.
The risk for travellers is generally low, but visiting areas where active outbreaks are occurring should be avoided. Understanding which specific viruses may be active in your destination is an important part of pre-travel health planning.
FAQs
In which countries are viral haemorrhagic fevers found, and does my occupation put me at greater risk?
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The major viral haemorrhagic fevers (VHFs) occur in different parts of the world. Lassa fever is mainly found in West Africa, Ebola and Marburg occur primarily in Central and East Africa, and Crimean-Congo haemorrhagic fever is found across parts of Africa, the Middle East, Eastern Europe, Central Asia, and China. As outbreaks can change over time, travellers should check the latest health advice before departure and during travel.
For most tourists, the risk of infection is very low. Higher-risk groups include healthcare workers, people working in rural or outbreak settings, those involved in animal slaughter, travellers exposed to ticks, or those with close contact with bats or other wildlife in affected areas. Anyone planning these activities should seek advice from a travel doctor before departure.
If I develop a fever after returning from a viral-haemorrhagic fever outbreak area what should I do?
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Anyone who develops a fever above 38°C within three weeks of returning from a viral haemorrhagic fever outbreak area should seek urgent medical attention. Call your doctor or the nearest hospital before attending in person, and tell them about your symptoms and recent travel. If you need an ambulance, advise the operator of your travel history before help arrives. This allows appropriate infection control measures to be put in place.
Be prepared to provide details of the countries and regions you visited, your travel dates, and any high-risk exposures, such as contact with bats or other wildlife, cave visits, tick bites, animal slaughter, attendance at funerals, or healthcare work. Promptly disclosing your travel history is one of the most important steps in ensuring the correct diagnosis and protecting healthcare workers and other patients.
Could I pass a viral haemorrhagic fever on to my family after returning to Australia?
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Some viral haemorrhagic fevers (VHFs), including Ebola, Marburg, and Lassa fever, can spread from person to person through direct contact with infected blood or other bodily fluids. In some cases, the virus can remain in certain body fluids after recovery, including semen, making sexual transmission possible for a period after illness.
If a traveller in Australia is diagnosed with a viral haemorrhagic fever, public health authorities will identify and monitor close contacts, and the patient will be isolated until they are no longer infectious. Household contacts should follow public health advice closely and seek immediate medical assessment if they develop symptoms. People recovering from a viral haemorrhagic fever are provided with medical advice regarding isolation, sexual activity, and any other precautions needed to prevent transmission.
Are viral haemorrhagic fevers notifiable in Australia, and what happens if a case is identified?
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Viral haemorrhagic fevers are classified as listed human diseases under Australia’s Biosecurity Act 2015, allowing the Australian Government to implement strict measures to prevent entry and respond rapidly to suspected cases. At the border, travellers may be screened, and anyone with symptoms consistent with a viral haemorrhagic fever may be referred for urgent medical care.
Within Australia, viral haemorrhagic fevers are urgently notifiable conditions in all states and territories. Doctors and laboratories must report suspected cases immediately, even before confirmation, so public health teams can begin contact tracing, arrange isolation, and coordinate specialist infectious disease care. This rapid-response system is designed to prevent any potential spread and ensure prompt, coordinated management of suspected or confirmed cases.
What to Know
Symptoms of Viral haemorrhagic fevers
Viral haemorrhagic fevers (VHFs) share several early symptoms, though severity varies by virus. Illness usually develops up to 9 days for Marburg virus disease, up to 13 days for Crimean-Congo haemorrhagic fever, and up to 21 days for Ebola virus disease and Lassa fever.
Early symptoms can begin gradually and may include fever, severe headache, muscle aches, and general fatigue. Other possible symptoms include chest pain, cough, abdominal pain, diarrhoea, conjunctivitis, facial swelling, and jaundice. Because these symptoms overlap with common illnesses such as malaria, typhoid, and influenza, VHF may not be suspected initially, particularly in returning travellers.
As illness progresses, some people recover whilst some develop bleeding of the nose or gums, vomiting, coughing blood, bruising and internal bleeding. Severe disease may result in multi-organ failure and death. Not all VHFs cause bleeding, and many cases, particularly Lassa fever, may be mild or even asymptomatic. Mortality varies widely, from around 1–15% in hospitalised Lassa fever cases to 50–90% in Ebola outbreaks.
People who recover from Ebola may experience long-term complications, including fatigue, joint and muscle pain, eye problems, and neurological symptoms lasting months or years.
Diagnosis and treatment of Viral haemorrhagic fevers
Diagnosis requires a high level of clinical suspicion and careful attention to travel and exposure history. Because early symptoms resemble many common infections, VHF should be considered in anyone who has been in a risk area and develops fever within the relevant incubation period.
Diagnosis is confirmed with specialised blood testing, usually PCR with or without serology, performed in high-biosafety public health laboratories.
If VHF is suspected, clinicians must notify public health authorities immediately by phone before test confirmation, so infection control measures can begin straight away. Patients require hospital assessment, and specialist infectious disease teams guide testing, isolation, and management.
Treatment depends on the type of virus, which may involve medications and intensive supportive care such as fluids, organ support and treatment of complications.
Prevention of Viral haemorrhagic fevers
Prevention focuses on avoiding exposure to animal reservoirs, vectors, and infected body fluids. Travellers to high-risk areas should avoid raw or undercooked meat, particularly from bats, primates, or monkeys, and maintain strict hand hygiene. Insect precautions such as repellent and protective clothing help reduce tick and mosquito exposure, and contact with rodents should be avoided.
Cave or mine visits in regions with Ebola or Marburg risk should be avoided during outbreaks due to potential exposure to infected bats. In areas where Crimean-Congo haemorrhagic fever occurs, those working with animals should avoid contact with blood or tissues and use appropriate protective equipment.
Anyone returning from an outbreak area who develops fever should call a doctor or hospital before attending in person, clearly stating travel history and symptoms. If emergency services are required, this information should be given before arrival. Early disclosure of travel history is critical for rapid diagnosis, isolation, and safe management.
If a VHF is diagnosed, preventing transmission includes isolation until no longer infectious, condom use after recovery until medically cleared, and following all infection-control advice, including mask use where recommended.