Ebola virus is a filovirus virus (filovirus) that causes severe fever, known as Ebola or FHV for viral haemorrhagic fever. Particularly virulent, the Ebola virus can cause death (between 25 and 90% of mortality according to epidemics). According to the WHO, the 2014 epidemic has a mortality rate of around 54%.
Ebola haemorrhagic fever is a very serious, contagious, life- threatening disease. WHO calls it “one of the most virulent diseases in the world”?
There is no treatment that can cure Ebola fever or a vaccine approved to prevent this Ebola haemorrhagic fever. The purpose of the care provided is to combat the symptoms caused by the disease and to help the patient survive the infection. There are some cases of cure following unauthorized treatment, which raises a lot of hope. Researchers are also working on developing a virus to fight this serious disease.
The Ebola virus can occur in all seasons and can affect anyone, men or women, young or old. Experts do not know why some people survive and others do not. Healed people can transmit the virus up to 7 weeks after their recovery. The dead can also transmit the disease.
The reservoirs of the Ebola virus are bats. They can transmit this virus to other animals, such as monkeys. Men can be contaminated via these animals (contact with their blood, eating their meat, etc.). Then, transmission during epidemics is between humans.
The outbreaks of epidemics are located in Africa. The Ebola virus was discovered in 1976 1 on the banks of the river of the same name, in former Zaire (now Democratic Republic of Congo). There are five forms: Bundibugyo, Ivory Coast, Reston, Sudan and Zaire. The latter is the shape that hits Africa in 2014. The first epidemic in 1976 killed 431 people. Then the epidemics succeeded one another. That of 2014, which seems to be the most serious epidemic, started in February and has already killed more than 2000 people 7 months later.
Prevalence of Ebola
At each outbreak, the Ebola virus affects a different number of people, and the percentage of deaths among people infected varies by epidemic. According to WHO, the 2014 epidemic would have a death rate of about 54%.
Diagnostic of Ebola
Viral haemorrhagic fever due to Ebola is difficult to diagnose. First, because the first symptoms can be related to other diseases such as malaria, or malaria , or cholera, or food poisoning. Secondly because it is almost impossible to perform blood tests in the regions concerned, because there is no high-security laboratory in the field. The presence of the Ebola virus is indeed affirmed following various blood testslike the Elisa test.
It is therefore very important to know if the person has been in contact with someone who has been infected with the Ebola virus in the previous three weeks or if he or she has attended a funeral by touching the deceased person within the previous three weeks.
Japanese researchers have recently developed a faster and less expensive screening test – a process that would yield a result in half an hour, but is not yet available.
Complications of Ebola
The Ebola virus causes fevers. The disease can progress to jaundice, delusions, convulsions, severe bleeding, and coma.
People recovering from Ebola virus disease carry the virus for weeks following infection and May, although cured, contaminate their loved ones. In addition, infected people are more contagious as their disease worsens.
Causes of Ebola
The Ebola virus would have as natural host some bats. This virus can be transmitted to animal species such as monkeys and chimpanzees. The latter can be transmitted to humans by body fluids, for example during the slaughter of an animal. Then, the virus is spread from person to person through direct contact (saliva, blood, urine, stool, sperm, vomiting or dirty clothing) or contaminated needles during medical care. Transmissions do not occur through the airways.
Infected people are contagious only at the onset of symptoms – there is indeed an incubation period (the period between the arrival of the virus in the body and the first signs of the disease) of several days (between 2 and 21).
After healing, a person can still be contagious for 7 weeks.
Infected people are still contagious after their death. Infections during funeral rites are also common.
Medical staff may also become infected if they do not use appropriate protective equipment: gloves, gowns, boots, masks, glasses.
The symptoms of Ebola
Once the virus has been transmitted, there is a phase where the infected person has no sign. This is called the silent phase, and it lasts between 2 and 21 days. During this period, it is impossible to detect the virus in the blood because it is too small, and we cannot treat the person.
Then, the first major symptoms of Ebola virus disease appear. The five most obvious symptoms are:
- The sudden onset of intense fever accompanied by chills;
- Extremely intense fatigue
- A significant loss of appetite (anorexia).
Other signs may be present:
- muscle aches;
- joint pain;
- irritation of the throat;
- abdominal pain;
And in case of aggravation:
- skin rash;
- chest pain;
- Red eyes;
- renal and hepatic insufficiency;
- Internal and external hemorrhages.
People at risk of Ebola
- People at risk are the relatives of the sick.
- Caregivers of people affected by Ebola also face a significant risk of becoming infected if they do not follow the protective guidelines.
- People in contact with contaminated meat such as the so-called “bush” (hunter, cutter, butcher, and cook) can also present a risk. These people can be the starting point of an epidemic.
Prevention involves avoiding the Ebola virus. It is advisable not to visit cities where an epidemic is rife.
For people living in an epidemic zone, some council prevails:
- Wash your hands regularly with soap and water
- Avoid being in contact with sick people, who must be quarantined. Does not touch, kiss, or even wash a sick person.
- Caregivers should wear gowns, gloves, masks and glasses. And do not reuse syringes.
- Special attention should be paid during funerary rites since the dead still carry the virus and can be contagious.
- Learn not to bring your hand to your mouth or eyes, the gateway to the virus.
- Wear gloves and protective clothing when handling sick animals and their flesh.
- Stay alert in cured patients who can still transmit the virus for 7 weeks. They must avoid sex during this time or use a condom.
Researchers are advancing on an Ebola vaccine, but the latter, which is promising, is not yet available.
Medical treatment of Ebola virus disease
There is no effective treatment that can cure Ebola. The care that can be provided is therefore to relieve the symptoms and increase the chances of a person suffering from the disease. In this case we speak of symptomatic care: maintain a proper blood pressure, fight against blood loss, and provide oxygen if necessary, rehydrate … Often dehydrated, the patients indeed need a rehydration.
Few cases of cure following the administration of an experimental treatment have been reported. For example, a contaminated Briton in Sierra Leone was treated in London with ZMapp, a treatment under development, and would be cured after 10 days of treatment. Two Americans have also benefited from this still experimental treatment that is not available for the populations concerned by this epidemic.
At the beginning of September 2014, WHO submitted to experts a list of 8 treatments and 2 vaccines to develop (the first tests on men were also advanced for one of the two vaccines). A recently published study in Nature Medicine suggested the efficacy of an experimental vaccine on monkeys.