What is Ebola?
Ebola virus is a severe disease caused by a virus. Previously known as Ebola Haemorrhagic Fever, it has a fatality rate of almost 90%. There are five strains of the Ebola virus – Zaire, Sudan, Tai Forest, Bundibugyo and Reston – and the Zaire strain is the most deadly.
Ebola was first detected in 1976 following an outbreak in the areas now known as Sudan and the Democratic Republic of the Congo. Sporadic outbreaks of Ebola have occurred in Central and East Africa in the intervening years, killing thousands of people, with the most recent outbreak the first to occur in West Africa.
Ebola virus is a serious illness that can lead to internal and external bleeding and can potentially cause multiple organ failure. There have been no cases of the virus in Australia, but good hygiene and infection control are essential to preventing the spread of the virus in affected countries. There is currently no vaccine for ebola virus.
How is it spread?
Ebola virus is thought to be present within fruit bats, which carry the disease but do not suffer any ill effects. It is then spread to the human population when people come into close contact with the blood, secretions, organs and bodily fluids of infected animals. The “bushmeat” trade, which involves the hunting and eating of wild animals such as primates and monkeys, is thought to play a large part in the outbreaks of Ebola.
Once in the human population, the virus spreads from person to person via direct contact with the blood, secretions or bodily fluid of an infected person. Blood, sweat, urine, faeces, vomit, saliva and breast milk can all spread Ebola. Contamination can also occur by coming into contact with environments contaminated with these fluids, such as doctors and nurses treating patients in a healthcare setting. With this in mind, traditional healing and burial practices in many parts of Africa affected by Ebola are thought to play a part in the spread of the disease.
Finally, transmission through sexual contact is also possible up to seven weeks after an infected person has recovered from the virus. However, airborne transmission does not occur.
What are its symptoms?
This serious and quite often fatal virus has an incubation period of between 2 and 21 days (on average it is around 8 to 10 days). Infected people aren’t contagious until they start to display symptoms. Ebola is initially characterised by the sudden onset of fever, aching muscles and joints, weakness, headache, fatigue and a sore throat.
This is closely followed by the second stage of symptoms, which includes vomiting, diarrhoea, a rash and impaired function of the liver and kidneys. Serious internal and external bleeding can also occur, such as blood in stool. This can then progress to multiple organ failure and, in many cases, death. Somewhere between 50% and 90% of Ebola patients will die from the disease.
Can it be prevented?
There is no vaccine for Ebola virus, although at the time of writing two potential vaccines were undergoing safety testing. It’s vital to exercise extreme caution when visiting areas affected by the virus. Avoiding contact with infected fruit bats and primates is essential, as is avoiding contact with anyone infected with Ebola.
However, if acting in a medical capacity to treat patients with Ebola, good hygiene practices must be followed. Wearing gloves and personal protective equipment, washing hands thoroughly and not reusing needles are all crucial to stopping the spread of the disease. Keeping patients in isolation is also important.
The World Health Organisation (WHO) advises that appropriate outbreak containment measures must be followed whenever there is an outbreak of Ebola. This includes the prompt and safe burial of the dead, identifying people who have come into contact with the virus and monitoring their health for three weeks, separating the healthy from the sick and maintaining a clean and hygienic environment.
WHO also recommends that male Ebola survivors practice safe sex for at least 12 months after the onset of symptoms, or until their semen has twice tested negative for the virus.
How is it diagnosed?
Due to the fact that the early symptoms of Ebola can mimic other conditions including the flu, typhoid fever and malaria, diagnosis of Ebola is not straightforward.
Ebola is diagnosed by a blood test that detects the virus. Urine or throat/nose swabs can also be examined to check for the virus. WHO lists the common tests that can be used to detect the Ebola virus as:
- Antibody-capture enzyme-linked immunosorbent assay (ELISA)
- Antigen-capture detection tests
- Serum neutralisation tests
- Reverse transcriptase polymerase chain reaction (RT-PCR) assay
- Electron microscopy
- Virus isolation by cell culture
Of course, as there are serious risks associated with testing patients for Ebola, high-level biological containment procedures should be followed at all times.
Are there any treatment options?
There is no cure or vaccine for Ebola and there is currently no specific treatment for people suffering from the virus. Instead, a range of supportive care measures are provided to ensure that patients are kept as comfortable as possible, including:
- Rehydration with oral and intravenous fluids
- Medication to control blood pressure
- Treating and preventing other infections
- Providing extra oxygen if required
These measures, while simple, can be life saving.