Key points
- The World Health Organization has declared an ebola virus disease outbreak in the Democratic Republic of the Congo and Uganda a public health emergency of international concern.
- Scientists at the CSIRO's Australian Centre for Disease Preparedness are among the only researchers in Australia who have worked with Ebolaviruses.
- While the current risk to Australia is very low, there are simple precautions that travellers to impacted areas can take.
The World Health Organization (WHO) has declared an outbreak of ebola virus disease (EVD) in the Democratic Republic of the Congo (DRC) and Uganda an international health emergency, due to the high number of suspected cases.
EVD is a severe, often fatal zoonotic disease, meaning the infection is passed from animals to humans and other primates. The current outbreak has led to a growing number of suspected cases and deaths, highlighting the need for coordinated global response efforts.
Professor Glenn Marsh, a virologist at CSIRO's high-biocontainment Australian Centre for Disease Preparedness (ACDP), is one of the few Australian researchers who has worked with live ebolaviruses. He answers some of the most common questions about these viruses. 
Are there different viruses that can cause EVD outbreaks?
There are six known types of ebolaviruses: Ebola virus, Sudan virus, Bundibugyo virus, Reston virus, Taï Forest virus, and Bombali virus.
Three of these have caused large outbreaks of EVD in people: Ebola virus, Sudan virus and Bundibugyo virus.
The current outbreak in the DRC and Uganda is caused by the Bundibugyo virus, which has previously been linked only to outbreaks in 2007-2008 and 2012.
Bundibugyo virus causes a disease that is indistinguishable from Ebola or Sudan viruses, however it does have a lower mortality rate (around 30% to 40%) compared to Ebola virus (up to 90%). Unlike the more common Ebola virus, the rarer Bundibugyo virus currently has no approved vaccines or targeted treatments, posing additional challenges for outbreak response and containment.
How is ebola transmitted?
Ebola viruses are "zoonotic", meaning they initially spread from animals to humans.
Fruit bats are considered the primary natural reservoir, though non-human primates like chimpanzees and gorillas are also known to be infected with the virus.
You cannot catch Ebola through casual contact like passing someone in public. Ebola spreads between people through direct contact with the body fluids of someone who is sick or has died from the disease. This includes blood, vomit, sweat, saliva, urine, or faeces. Ebola can also spread by contact with objects like clothing, bedding or medical equipment that have been contaminated. People are most infectious once they start to feel unwell.
The virus enters the body through broken skin or through sensitive areas such as the eyes, nose, or mouth. It does not spread through the air like the flu or COVID-19.
What is the risk to Australia?
The current risk to Australia is very low, and there has never been a case recorded here.
While the virus could be imported by a traveller returning from an affected region, transmission requires close contact with body fluids of someone who is visibly unwell, which makes detection and containment much easier. Australia also has strong border screening and public health systems in place to rapidly identify and manage any suspected cases.
What ebola research has CSIRO done?
Researchers at CSIRO Australian Centre for Disease Preparedness have been studying Ebolaviruses for the past 15 years. 
In a world-first breakthrough in 2014, the team successfully proved that ferrets could be used to study how the virus causes disease as they can often mimic how the disease appears in humans. This work then allowed them to safely test potential vaccines for both the Ebola and Sudan viruses. They also used lab-grown cells that mimic human tissues to figure out why some Ebola strains are deadly to humans while others are not.
CSIRO researchers also worked to understand how these viruses spread between animals and humans. Researchers tracked how viruses jump between species, studying how the Reston virus affects pigs – work they have now expanded to include the Marburg virus.
Closer to home, their tracking even uncovered clues in our own backyard, discovering antibodies to a new type of ebolavirus in Australian bats. There is no evidence that a disease-causing ebolavirus is present in bats or any other animals in Australia.
What precautions should travellers be taking?
Travellers to outbreak areas can greatly reduce their risk by taking simple precautions . The most important is to avoid close contact with anyone who is unwell, particularly if they have symptoms like fever or vomiting. It is also important to avoid any contact with body fluids, as well as objects that may be contaminated.
Good hygiene , such as regular handwashing or using hand sanitiser, is essential. Travellers should also avoid contact with the bodies of people who have died from the suspected illness, including during funerals, and stay away from wildlife such as bats and primates. After returning home, it's important to monitor for symptoms and seek medical advice promptly if feeling unwell.
Anyone travelling to Africa should check the Smart Traveller website for local health advice, including the latest updates on Ebola outbreaks.
