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Not least because of the dramatic course of the disease, Ebola is considered to be one of the most dangerous diseases worldwide, even if outbreaks are rare and the epidemics have so far been limited to a few African countries. Infections with the Ebola virus are feared primarily because no efficient treatment is known to date and because the viruses lead to the death of patients in up to 90 percent of cases. In addition, there is the dramatic clinical picture with bleeding from the mucous membranes and bleeding into the upper layers of the skin. Those affected bleed from practically all body openings.
The Ebola virus
Ebola fever is triggered by viruses from the Filoviridae family. Five different strains of the Ebola virus (Bundibugyo, Zaire, Reston, Sudan and Taï Wald Ebola virus) are known, whereby according to the Robert Koch Institute (RKI) so far "out of the five known species of Ebola virus, three species large outbreaks in humans (Zaire, Sudan, Bundibugyo) ”. In addition to humans, primates such as gorillas or chimpanzees as so-called false hosts are also potential victims of the infections.
For a long time there was uncertainty about the natural reservoir of viruses. Today, according to the World Health Organization (WHO), "fruit bats, especially the genera Hypsignathus monstrosus, Epomops franqueti and Myonycteris torquata, are considered to be possible natural hosts for the Ebola virus." This could also explain the geographical distribution of the viruses on the sub-Saharan African continent. Human infections were first detected in 1976 with two simultaneous outbreaks in Sudan and the Democratic Republic of the Congo (formerly Zaire). The virus was named after the Ebola River, which was located in the immediate vicinity of the village in the Democratic Republic of the Congo, which was significantly affected. According to the RKI, the viruses are able to "multiply in almost all cells of the host", whereby "due to the rapid virus synthesis, a virus crystal (crystalloid) emerges, which penetrates outwards from the area of the cell nucleus and individual viruses Lyse leaves the cell free. "
Symptoms of Ebola virus infection
According to the WHO, the first symptoms of the infection can be observed after an incubation period of two to 21 days. Ebola fever usually begins with flu-like symptoms such as body aches, headaches, sore throats and fever. In the further course, the fever reaches body temperatures of more than 38.5 degrees Celsius and the sufferers suffer from massive diarrhea, nausea and vomiting. In addition, there are the typical bleeding of a so-called hemorrhagic fever. "Internal bleeding, bleeding into the tissue (bruises), bloody stools and urine" and "bleeding from the skin and mucous membranes" are mentioned here by the RKI as possible consequences of the infection. According to the RKI, other Ebola symptoms include "liver and kidney dysfunction with edema, shock and circulatory breakdown, cramps and paralysis."
With the spread of the infection in the organism, the capillary blood vessels are increasingly destroyed, whereby “bleeding in particular in the gastrointestinal tract, spleen and lungs” leads to the death of the patients, reports the RKI. The head of virology at the Bernhard Nocht Institute (BNI), Professor Stephan Günther, sees things a little differently and explains: "Most patients probably die from organ failure, not from bleeding." Regardless of the acute cause of the death of the Due to the infection, experts agree that up to 90 percent of infections can be fatal among aggressive strains.
The virus can be transmitted through the blood, other bodily fluids or tissue of infected humans and animals, whereby according to the WHO in Africa, for example, "infections are documented by the handling of infected chimpanzees, gorillas, fruit bats, monkeys, antelopes and porcupines." Infection risk is generally rated as high when in direct contact with infected people. This also applies after death, when mourners at funerals come into contact with the body of the deceased, reports the WHO. In addition, “men who have recovered from the disease could transmit the virus through their sperm for up to seven weeks after recovery.” Infection via contaminated food or the contaminated surroundings of sick people is also possible. As the latter depend on intensive care during the illness and the hygienic precautions on site are often inadequate, transmission to others is not uncommon.
A reliable Ebola diagnosis can be made using various tests in the laboratory. Here the WHO calls the so-called ELISA test (ELISA: Enzyme Linked Immunosorbent Assay), the antigen detection test, the serum neutralization test, the investigation of the reverse transcriptase-polymerase chain reaction (RT-PCR), electron microscopy and virus isolation using cell culture. Since the samples of the patients represent an extreme biological risk, the tests are to be carried out according to the WHO, "under maximum biological safety conditions." Laboratory diagnostics must be carried out in a special laboratory of protection level 4, in Germany "for the microbiological diagnosis of filoviruses with the Philipps University of Marburg and the Bernhard Nocht Institute in Hamburg have two facilities available, ”explains the RKI.
In advance of the laboratory diagnostic search for the Ebola virus, according to the RKI, diseases caused by other pathogens that can trigger a viral hemorrhagic fever, such as the lassavirus, representatives of hantaviruses, the Crimean Congo virus or the dengue virus, should be excluded. Non-viral diseases such as malaria, typhoid abdominalis or rickettsioses should also be excluded in the course of differential diagnosis.
To date, there are no effective treatment options or medication for Ebola virus infection. The patients need intensive medical care and should be isolated "in a suitable treatment center for highly contagious diseases (special isolation station)", reports the RKI. Therapeutic care focuses on symptom relief. For example, infusions and circulatory stabilizing drugs are used, explains BNI expert Professor Stephan Günther. In addition, there is the possibility in Europe to stabilize the patient's condition by means of "artificial respiration, dialysis, blood replacement, that is, everything that modern intensive care medicine has to offer". In case of doubt, however, intensive care medicine cannot save the lives of patients.
After the first outbreak was registered in what was then Zaire (now the Democratic Republic of the Congo) in 1976, further epidemics followed in central African countries such as Gabon, Uganda or Sudan. The biggest epidemic to date, however, began in February 2014 in West Africa, where Ebola infections from Guinea also spread to the neighboring states of Sierra Leone and Liberia. By mid-July 2014, more than 600 people had succumbed to the consequences of Ebola and around 1,000 people were infected. An end to the wave of infections was only in sight a year and a half later. The sheer number of victims and the difficult local conditions made it difficult for relief organizations and national health authorities to curb the disease. There were also many reservations among the population about the helpers, and since Ebola had never appeared in West Africa before, there was a lack of knowledge about infection routes and the necessary hygiene precautions. The situation was only somewhat mitigated by the fact that the pathogen strain did not result in patient death in 90 percent of the cases, but only in around 60 percent of the infections. In total, around 28,000 people became infected as a result of the epidemic in Guinea, Liberia and Sierra Leone, and around 11,300 died from the consequences of the infection. (fp)
Author and source information
This text corresponds to the requirements of the medical literature, medical guidelines and current studies and has been checked by medical doctors.
Dipl. Geogr. Fabian Peters
- Matthew E. Levison: Marburg and Ebola Virus Infections, MSD Manual, (accessed October 3, 2019), MSD
- Robert Koch Institute: Ebola fever, (accessed 03.10.2019), RKI
- World Health Organization: Ebola virus disease, (accessed 03.10.2019), WHO
- Norbert Suttorp: Infectious Diseases, Thieme Verlag, 1st edition, 2003