Ebola virus disease

Ebola virus disease, or Ebola for short, is a rare but life-threatening infectious disease that is caused by the Ebola virus. To date, outbreaks of the disease have only ever occurred in sub-Saharan Africa. The virus took its name from the Congolese Ebola River, which is located near the site of the first known outbreak.

Outbreaks frequently occur in the Democratic Republic of the Congo but also in other African countries. A major outbreak occurred in West Africa between 2014 and 2016. More than 28,000 people were infected and over 11,000 people died.

The Ebola virus is closely related to the Marburg virus, which has a similar spread, is transmitted in the same way and even causes the same symptoms.

The early symptoms are non-specific and resemble those of the flu: high temperature, fatigue, aching limbs and a general sense of feeling unwell. The additional symptoms of upper abdomen pain, nausea, vomiting and diarrhea can develop after 3 to 10 days.

Further symptoms are also possible as the disease progresses. These include:

• red eyes
• headache and chest pain
• joint and muscle pain
• difficulty swallowing
• internal and external bleeding
• delirium and shortness of breath

Some patients can experience health issues even after recovering from an infection. Such cases are termed post-Ebola syndrome and manifest themselves in the form of muscle and joint pain, headaches and sight and hearing problems. The cause is not yet known.

Answers to frequently asked questions about Ebola virus disease can be found on the website of the Robert Koch Institute.

The Ebola virus is found in nature in wild animals, for example in certain species of fruit bats. When these animals are hunted, the virus comes into contact with humans. The Ebola virus is transmitted from person to person via bodily fluids.

Transmission from person to person

Transmission occurs through direct physical contact with Ebola patients or people who have died of Ebola virus disease. Direct contact with bodily fluids such as blood, saliva, sweat, urine, stool or vomit is particularly risky.

People infected with the Ebola virus are only contagious once they display symptoms. An average of 8 to 9 days pass between infection and the onset of symptoms although this period can range from 2 days to 3 weeks. The more severe the health issues become as the disease progresses, the greater the risk of contagion.

Patients are classed as no longer contagious several days after their symptoms have disappeared. However, the virus can still be transmitted by sperm during sexual intercourse for several months.

Transmission by objects

For a certain time, the virus can also be transmitted via objects that have come into contact with infectious liquids. These can include needles, surgical equipment, clothing and bed linen.

Transmission by animals

The Ebola virus can also be transmitted to humans through contact with infected animals or animal products. Specifically, this can occur during hunting or slaughter as well as when preparing and eating infected wild animals (“bushmeat”) from affected areas. This is also likely to trigger an Ebola outbreak.

Anyone who has not been vaccinated has a high risk of infection in the event of unprotected direct contact with bodily fluids and secretions from Ebola patients and people who have died of the disease. These include blood, saliva, sweat, urine, stool or vomit.

Transmission through droplet infection (e.g. by sneezing) is rare but possible.

The high risk of fatality means that the strictest safety precautions apply when dealing with patients and the deceased.

To date, Ebola outbreaks have only ever occurred in sub-Saharan Africa. They have been registered in Central Africa since 1976, including repeatedly in the Democratic Republic of the Congo, Gabon, the Republic of the Congo, present-day South Sudan and Uganda.

The outbreak from 2014 to 2016, on the other hand, particularly affected the West African countries of Guinea, Sierra Leone and Liberia. This also resulted in cases in Mali and Nigeria. During this outbreak, a number of Ebola cases were also recorded in the USA and Europe. However, the risk of a full outbreak in Europe is considered to be extremely low.

Ebola virus disease progresses in three phases:

Early fever phase

About 8 to 9 days after infection, non-specific Ebola virus disease symptoms begin, such as high temperature, headache, muscle pain and fatigue.

Gastrointestinal tract phase

A few days after the onset of the disease, the additional symptoms of nausea, vomiting, diarrhea and upper abdominal pain also appear. Some patients also experience conjunctivitis, pharyngitis, hiccups, mental confusion (delirium) or a rash.

As the disease progresses, internal bleeding may occur. This particularly affects the digestive tract, lungs and gums.

Improvement or deterioration phase

Whereas some patients next start to slowly improve, others’ health deteriorates. This is due to a general coagulation disorder, which causes a loss of fluid, bleeding and the failure of various organs. This development can be fatal. Between 30 and 90 percent of patients die from Ebola virus disease.

A vaccine has been approved in the European Union since November 2019. This is classed as safe and highly effective. Further vaccines are currently being tested in clinical studies. Preliminary results show these to be extremely effective too.

Diagnosis occurs using a blood sample or bodily fluids such as urine. In some cases, it is only possible to detect the Ebola virus from the third day after the onset of the symptoms.

No proven causal treatment for Ebola virus disease yet exists. Instead, the symptoms are treated. It is particularly important to keep the patient’s fluid, electrolyte and glucose levels stable.