The Ebola virus is transmitted by direct contact with infected body fluids. These include blood, saliva, urine, diarrhea, or semen. Therefore, most people are vulnerable, who are in close contact with infected people, so family members, doctors or nurses. Even animals can infect people with the virus. Risk animals are monkeys, bats (especially bats) and antelopes. So far there is no evidence that Ebola is transmitted from person to person through the air. Studies have found, however, that animals have been infected via air transmission as well. The Ebola incubation period, the time from infection to onset of the disease, is between two days and three weeks.
There are five different strains of the virus. Four of these are the most dangerous to people. Depending on the virus strain and medical care about 50 to 90 percent of patients die. In the current outbreak, the death rate according to the WHO is at 70 percent. Most patients probably die of organ failure, which is triggered by blood clotting.
Doctors can only guess – the exact science is quite complex and all the effect of the virus are not yet explained, since Ebola has not been explored in detail in humans. Current findings indicate that the virus is thought to act as deadly because it triggers a complex reaction in the human body compared to others. First, it multiplies rapidly. At the same time it acts by weakening the immune system: The body’s defenses become significantly inhibited in many people and the body becomes inundated with the virus. This is accompanied by a strong inflammatory response in the body.
In addition, the Ebola virus infects the cells of the inner walls of blood vessels and targets and affects the platelets in the blood. This in turn produces a chemical which creates holes the size of a cell into the walls of capillaries and leads to internal bleeding. The massive bleeding causes high fluid loss that can lead to shock and multiorgan failure. However, the very high mortality rate in Africa is also a consequence of poverty in the countries concerned: ill patients are misdiagnosed as such and there is a lack of medical infrastructure to provide the infusions that would allow the patient a higher chance of survival.
No. However, experts suggest that the mortality rate in specialized clinics is much lower – with probably less than 50 percent. This is partly because patients have access to good medical care including replacing fluid loss by infusions, thus gaining precious time for the patient. The body’s immune system then has more time to prevail against the virus. Also new drugs offer hope.
A residual risk remains. Volunteers are severely compromised as soon as they become infected in any case. However, the overall risk, according to information from specialists and WHO are relatively low. The protective gear has proven to help very efficiently from infections in the crisis areas in contact with the Ebola patients. The risk is probably comparable to the risk of becoming a victim of a car accident or the chance of infection faced by first responders.
In the countries concerned, the medical equipment is missing to stop the disease. In addition, the population does not work well with the assistants. In West Africa, the people do not trust hospitals and therefore rarely seek out medical help. Many people need to be told how a virus works. In the villages, it is often tradition to touch and wash the dead. Due to the poor infrastructure in West Africa educating the population is difficult. Also, many people go deep into the forest to hunt, so that increases the risk of coming into contact with infected animals.
Particularly through improved education of the population and thereby improved hygiene measures. But the widespread illiteracy and poor infrastructure does not make this easy. It’s very important know with whom the infected have been in contact so that these individuals may be observed for any symptoms. More assistants would also improve the situation, because overwork and fatigue often lead to neglect of precautions and rules of conduct.
The classification is a legally binding health provision. It gives the WHO the opportunity to adopt global rules to curb the Ebola outbreak. Some of the rules may be quarantine measures such as border closures and restrictions in international travel. The disease experts also suggested measures to contain the Ebola virus in affected countries. These include: the proclamation of national emergency or establishment of national crisis centers to coordinate prevention and emergency procedures, including local forces (tribal elders, clan chiefs, etc.) and full coverage of medical goods, particularly protective clothing.
The WHO has dampened hopes for a soon that becomes available drug against Ebola. Of the more than 120 drugs put forward to the agency, only a very small number are both suitable and available for human trial, Martin Friede of the WHO’s public health, innovation and intellectual property division, told reporters. “We don’t have actually a lot of drugs in our pipeline that look promising,” he acknowledged. Hope rose about the drug Lamivudine otherwise used in HIV patients after a doctor had used it and other followed him. It has been found, however, that the Lamivudine had no effect on Ebola. The success of the drug ZMapp the California biotech company Mapp Biopharmaceuticals so far can not be detected, the scientists said. Two Americans workers infected with Ebola had received the ZMapp and soon recovered. However, the positive course of their recovery could be the result of good medical care or because the patients were well nourished and in good health before their infection. Similarly, other medications may have played a role, as the patient had received two to four different preparations.
There is no vaccine that we know of. In several countries, tests with potentially promising materials have begun. One of the first trials that showed promising results is the vaccine, called ChAD3 was co-developed by National Institutes of Health (NIH) and by the NIH’s National Institute of Allergy and Infectious Diseases (NIAID) and Okairos, a biotechnology company acquired by GlaxoSmithKline (GSK) in 2013. It uses a type of chimpanzee cold virus, known as chimpanzee adenovirus type 3 (ChAd3), as a carrier to deliver genetic material from two strains of the Ebola virus – the Sudan strain and the Zaire strain, which is responsible for the current Ebola outbreak in west Africa. In monkeys, it offers good protection from infection. When people were first tested, it was successful and all subjects developed antibodies to Ebola. However, extensive further testing must follow.
Since 10 November, 34 volunteers have been vaccinated with the shot, known as VSV-ZEBOV Ebola vaccine, at the request of the World Health Organization (WHO). The experimental vaccine was developed by Merck and NewLink and trials have also begun in the United States, Canada, Germany and Gabon, and similar trials should start soon in Kenya. However, the clinical trials of this particular Ebola vaccine has been halted temporarily as a precautionary measure after four patients complained of joint pains.