Ebola is a serious, very often fatal infectious disease. The causative agent is the Ebola virus. Eponym for the virus is the river Ebola in the Democratic Republic of the Congo. Near the river, the viruses caused the first known large Ebola outbreak in 1976. Like Lassa, Ebola is one of the haemorrhagic fever diseases. Characteristic of these diseases are heavy bleeding and fever.
Since 1976, reports of Ebola outbreaks have been repeated. There were epidemics mainly in the Democratic Republic of Congo (formerly Zaire), the Republic of Congo, in today's South Sudan, Gabon and Uganda. The Ebola epidemic, which broke out in Guinea, West Africa in March 2014, caused quite a stir. From there, the Ebola virus spread to neighboring countries. Ebola cases have also been reported from the US, England and Spain, where holidaymakers and crisis workers carried the virus. Meanwhile, the biggest ever Ebola epidemic is over. The WHO declared Sierra Leone as being free of euthanasia in March 2016, Guinea and Liberia followed in June 2016. By then, at least 28,600 people had contracted Ebola, more than 11,000 died.
Ebola usually runs in four phases.
- Phase (influenza-like syndrome): After an incubation period (period from the onset of an illness to the first symptoms) of 2 to 21 days - usually 8 to 10 days - there are flu-like symptoms with headache, aching muscles and limbs as well as fatigue and weakness,
- Phase (acute phase or gastrointestinal phase): From day 3 to 10 after onset of the disease, chills and fever that are neither antimalarial nor antibiotic sensitive are typical. There are also nausea, vomiting and diarrhea; sometimes upper abdominal and lower abdominal pain, loss of appetite, edema, pronounced physical weakness, dizziness, dysphagia, hiccups, reddened oral mucosa and conjunctivitis. 25 to 50 percent of those infected develop a rash.
- Phase (pseudo-remission): On days 7 to 10 (12) sufferers suddenly feel better, are increasingly resilient, have an appetite and can eat. Many believe that they have overcome the infection. In rare cases it is like that. But usually follows the fourth and most violent phase.
- Phase (hemorrhagic phase): The hemorrhagic phase of Ebola usually begins on day 10. It is characterized by hemorrhages in the skin, mucous membrane, conjunctiva, tissues and organs. Injection sites also bleed more. Over time, the organs fail, the circulation collapses, a shock symptom sets in, respiration stops and the heart stops beating. Occasionally there are also cramps, disorders of consciousness, confusion, hearing loss and a distorted or delusional perception of the outside world (delirium). In Phase 4, Ebola sufferers, even in intensive care, are all too often beyond salvation.
Ebola viruses are among the most aggressive species of their kind. Like the highly dangerous Marburg virus, the Ebola virus belongs to the group of filoviruses. Therefore, the symptoms of both infectious diseases are similar. In the case of the Ebola virus, scientists distinguish five different forms:
- Zaire-Ebola virus (EBOV)
- Sudan Ebola virus (SUDV)
- Reston Ebola virus (RESTV)
- Taï Forest Ebola Virus or former Ivory Coast Ebola Virus (TAFV)
- Bundibugyo-Ebola virus (BDBV).
Transmission of viruses
Ebola viruses reach the human organism in different ways. They are transmitted by infected people through blood, excretions and Körpersekrete. In addition, sick animals such as fruit bats, bats or monkeys and their meat (during hunting, dissection, preparation or consumption) as well as contaminated items such as mattresses, syringes and other medical cutlery can transmit the Ebola virus.
The symptoms of Ebola do not allow a clear diagnosis. Many haemorrhagic fevers are similar in their symptoms. Clear results only bring laboratory tests. Thus, Ebola viruses can be detected in blood, urine or saliva. In addition, antibody detection is possible. However, antibodies do not form until later in the disease process.
Ebola samples may only be analyzed in specialized laboratories with the highest level of security (Level IV). In Germany, the direct or indirect pathogen detection must be reported according to the Infection Protection Act (IfSG). This applies to suspected Ebola, the disease and death by Ebola.
So far, there is no effective treatment for Ebola. Even at the slightest suspicion of Ebola, those affected must be isolated and treated in special intensive care departments for highly infectious diseases. However, there is no mature standardized treatment concept even for special wards. The Ebola therapy focuses rather on individually to combat the symptoms. As a priority, antipyretic measures and analgesics are used.In addition, the water and electrolyte balance and balanced, as well as the glucose metabolism. Depending on the degree of bleeding and organ involvement, further therapeutic measures such as dialysis and cardiovascular stabilization are necessary.
The chances of recovery or prognosis (survival probability) of Ebola depend on which genus of the pathogen causes the disease. For example, the Bundibugyo-Ebola virus has a mortality risk of up to 36 percent. By comparison, up to 90 percent of Zaire-Ebola virus infections are fatal. Due to the immense lethality (death rate) and high risk of infection, all ebolaviruses - with the exception of the RESTV - are classified in the highest risk group (IV) according to the Biological Agents Ordinance. For working with the viruses and infected patients therefore highest security levels apply.
Before traveling to ebony-endangered areas, holidaymakers and medical personnel should inform themselves at the Federal Foreign Office about safety and security measures. In general, a close (unprotected) contact with Ebola-infected and Ebola-deceased should be avoided. This also applies to potentially infectious animals or their meat. Contaminated items should be cleaned and disinfected. This also applies to the hands. The best way to provide travelers with suitable disinfectants before the holiday begins. These are, for example, special disinfectant solutions such as Sterilium virugard, Octenisept or chloramine T.
Prophylaxis after pathogen contact
Following a possible contact with Ebola viruses, the Robert Koch Institute (RKI) recommends specific skin and mucous membrane disinfectants (so-called post-exposure prophylaxis). Medical personnel must wear special protective clothing and should be specially trained.
Antiviral agents such as ribavirin have no effect on Ebola. Favipiravir or other active substances are not approved as medicinal products in Germany. After written documentation and explanation the administration of these active substances after individual examination under certain conditions is nevertheless possible.
Ebola vaccines - test results promising
So far there is no approved vaccine against Ebola. However, the development of vaccines is already well advanced. The test results are promising and let hope infection medicine. The two most important experimental vaccines are currently VSV-ZEBOV and ChAd3-Ebola. VSV-ZEBOV convinced in 2015 in a clinical study (Phase III study) in West Africa with an efficacy of 100 percent. Any use is already possible, but must be checked individually.
Worldwide, further vaccines against the deadly Ebola virus are being researched at various stages of development. Scientists and physicians alike are confident that effective vaccine protection will be available in the near future.