Ebola: Description
Ebola (Ebola fever) is a severe viral infection that belongs to the so-called hemorrhagic fevers. These are infectious diseases associated with fever and increased bleeding tendency (including internal bleeding). The risk area is primarily equatorial Africa, where medical care is often inadequate.
The first infection with the Ebola virus was described in the 1970s in Sudan and Congo. Since then, there have been repeated Ebola epidemics. In the past, the disease could mostly be contained by strict isolation of infected persons, which prevented larger epidemics. In addition, the high mortality rate also limits its spread. Death often occurs after only a few days. To date, there are no uniform standards for the treatment of Ebola.
Because of the great danger posed by Ebola, the pathogen is being discussed as a possible warfare agent. However, so far there are no indications of such a use. An attempt by the Japanese Aum sect to use Ebola viruses for terrorist attacks in Japan failed.
A pathogen very similar to the Ebola virus is the Marburg virus, also a hemorrhagic fever. Both viruses belong to the filovirus family. They cause diseases with similar courses that cannot be clearly distinguished from each other.
Ebola is notifiable
Ebola: Symptoms
It takes 2 to 21 days (eight to nine days on average) between infection and Ebola outbreak. Symptoms include:
- headache and aching limbs
- high fever (may subside in the meantime, but the disease then often takes a more severe course later on)
- conjunctivitis
- nausea
- skin rash
In addition, kidney and liver function may be disturbed.
Already a few days after the outbreak of the disease, severe internal and external bleeding may occur, mainly originating from the mucous membranes. In addition to the eye and gastrointestinal tract, other organs may also be affected.
As Ebola progresses, various organs often fail. Brain inflammation (encephalitis) can also occur, further worsening the prognosis. Severe cases of the disease are similar to septic shock and can be fatal. The cause of death is often heart failure.
The described course of the disease is not specific for Ebola! Fever, bleeding and organ damage also occur in other severe infections. This makes it difficult for doctors to make an accurate diagnosis at first.
Ebola: Causes and risk factors
The disease is caused by the Ebola virus, of which five strains are known. So far, three of these viral strains have caused large outbreaks of disease in humans.
Infection from animal to human
For this reason, diseased animals should be quarantined as soon as possible. The carcasses of dead animals must be disposed of carefully. Raw meat from these animals should not be consumed.
Unlike many other tropical infections, transmission of the Ebola virus through mosquito bites is not known to date.
Infection from person to person
Ebola infection from person to person usually occurs only through close contact. In rare cases, the Ebola virus can also be transmitted by coughing (droplet infection).
Infected persons are contagious as long as symptoms of disease persist. Infections during the incubation period (= phase between infection and outbreak of first symptoms) have not been reported so far.
In particular, relatives and caregivers of Ebola patients are at high risk of becoming infected as well. During an outbreak in Uganda in 2000, 60 percent of the nursing staff were infected with the virus. Therefore, Ebola patients must be strictly isolated. All physical contact and sharing of items such as cutlery should be avoided.
Persons who have been in very close physical contact with the patient (e.g., life partners, children) may also be isolated. In any case, the body temperature of each contact person should be checked regularly.
Risk of infection when traveling to Ebola areas
According to experts, there is usually no increased risk of infection for travelers to areas where Ebola occurs (especially tropical rainforests in Central Africa). Only those who have close contact with infected persons are at high risk. Nevertheless, all vacationers should inform themselves about the current health situation in the destination region before starting their trip.
Ebola is notifiable
Early warning systems for Ebola are essential to prevent or contain major outbreaks. In Germany, Austria and Switzerland, even suspected cases of Ebola infection must be reported by physicians to the responsible health authority, stating the patient’s name.
Ebola: examinations and diagnosis
Especially in the early phase of the disease, it is difficult to distinguish between Ebola fever and other diseases such as yellow fever, Lassa fever, dengue fever or even malaria. In suspected cases, patients must be isolated early. Samples are taken and examined for the Ebola virus. The pathogen can be detected primarily in the blood, but also in the skin. Antibodies against the virus are usually only formed later in the course of the disease.
Only specialized laboratories of the highest security level are allowed to work with the Ebola virus and examine sample material from patients suspected of having Ebola.
Ebola: Treatment
To date, there is no specific treatment for Ebola, which is why mortality is very high. Likewise, there are no standardized treatment recommendations. Therapy with an antiviral drug can be considered, but so far – unlike with similar viral diseases – has hardly been successful.
However, recent studies with two new antibody preparations against Ebola give hope: according to current results, they can apparently cure up to 90 percent of patients if administered early. In the USA, they have already been approved as drugs against Ebola (in October and December 2020, respectively). There is no approval (yet) for Europe.
Here, an Ebola infection can so far only be treated symptomatically. Patients are given intensive medical care if possible. Sufficient fluid intake with electrolytes is particularly important. In the event of (imminent) organ failure, organ replacement procedures must be started quickly, such as dialysis for kidney failure.
In some cases, Ebola patients are also given antibiotics to combat secondary bacterial infections that can more easily affect the diseased body. Sedatives can also be important to relieve patients’ anxiety. Additionally, it is essential to control blood clotting.
Ebola: course of the disease and prognosis
The generally poor prognosis of the disease is also due to the poorly developed healthcare systems in the areas where the Ebola virus spreads. Symptoms and organ failure often require expensive and modern treatment methods, which are usually not available in such countries.
For these reasons, Ebola leads to death in 25 to 90 percent of cases. Those infected often die within days of the onset of the disease. Survivors of an Ebola infection often have to deal with long-term consequences such as psychosis and liver inflammation (hepatitis).
Ebola: Prevention
Two vaccines against Ebola have been approved so far in the EU and some other countries:
The first received its approval in 2019, which is a live vaccine that can be administered to adults as an injection into a muscle (no approval for children). In this case, one vaccine dose is sufficient. This apparently protects very effectively against infection. Even people who have already had contact with the Ebola virus, the vaccination still offers a certain protection. Those who contract Ebola despite vaccination usually experience a milder course of the disease. It is not yet known how long the effect of the live vaccine will last.
