1. The Ebola virus is a virus that belongs to the Filoviridae family of viruses. It causes a severe disease that has fatal consequences in the majority of the cases. Ebola appeared in 1976 in Africa when two deadly outbreaks happened. Besides, the Ebola virus is a general name that comprises a few species such as Bundibugyo ebolavirus, Zaire ebolavirus, Sudan ebolavirus, Reston ebolavirus, and Tai Forest ebolavirus, also known by its former name as Cote d’Ivoire ebolavirus (World Health Organization, 2011, p. 3). The majority of these subtypes (4 out of 5) originates from Africa and occurs in an animal host. The pathogenicity of virus varies from one subtype to another. Zaire ebolavirus led to outbreaks in Africa and has been highly lethal in humans, while Reston ebolavirus infects mostly animals.
The main symptoms in humans are: high temperature, headache, sore throat, muscle pain, severe fever and intense weakness. People also suffer from vomiting, rash, and diarrhea, followed by problems of kidney and liver function. Sometimes there can be internal or external bleeding. The disease is highly contagious and has 2 to 21 incubation period. A person is infectious as long as his or her blood or other secretions (for example, semen) contains virus.
2. The Ebola virus is transmitted by direct contact and respiratory droplet with both humans and animals. It can spread through various communities within a very short period of time. Even dead people carry the infection, which would be transmitted through handling of the body or direct contact. The Ebola virus has an interesting mechanism of entry and exit. It enters the body through various ways, but mostly mucous membranes. It breaks in the skin, or parenterally. The next way of evolution of the virus in the body causes infection to cells of different types. The first and the major infection attack falls to macrophages and dendritic cells. The virus replicates with a high speed causing necrosis of ubiquitous “sentinel” cells. After the cells are damaged, a large number of new contagious viral particles are released and infects new cells by entering extracellular fluid. Further contagion is facilitated by “virus-induced suppression of type I interferon responses” (Bray & Chertow, 2016). With the large number of cells and tissues damaged, virus leaves the body through such channels as oral, conjuctival, respiratory fluids. Vomiting, bleeding and diarrhea are also the ways how virus leaves the body.
3. The presence of the virus in the body is detectable one day before the symptoms appear. The fatality rate of the disease caused by the virus varies from 44 to 90%, which depends on the subtype of the virus. The pathogenesis of the disease still is not studied in full. The virus enters the body through direct contact with mucosal surfaces or skin injuries. It suppresses the immune system and causes an inflammatory response of the body. The damage to the vascular and immune systems may lead to multiorgan failure and shock (for example, liver and kidney failures). Non-human studies demonstrated that the Ebola virus “replicates in monocytes, macrophages, and dendritic cells” (Michalek, Krejcova, Adam & Kizek, 2015, p. 50). However, the virus still can be found in endothelial cells and adrenal cells as well as in fibroblasts and hepatocytes.
Patients diagnosed with Ebola often suffer from gastrointestinal dysfunction, however, the mechanism of the influence of the virus on these organs is not known in full. The virus causes extensive tissue damage, which evokes a systemic inflammatory syndrome. Huge number of cells released at that time becomes a new source of infection. Probably, this response of the body induces gastrointestinal dysfunction. In addition, the immune system response leads to coagulation defects. Severity of the Ebola disease can be explained by these two processes in the body (Bray & Chertow, 2016).
4. The disease caused by the Ebola virus raises serious concerns to epidemiologists due to its fatality and fast progression. Moreover, still very little evidence is available regarding its progression in the body and its pathogenesis. Since it was first diagnosed in Africa in 1976, massive outbreaks were rare cases. However, the epidemic in 2014-2015 made the entire health community to worry regarding the scope of its transmission. With the world getting more and more globalized and people travelling easily from one part of the world to another, local epidemic may easily become global pandemic.
Besides, the Ebola virus is one of the less studied viruses in the current medical practice. It is still unclear how some people manage to develop immunity against the disease. Meanwhile, there is no cure or vaccine against this virus. People may be isolated for preventing further transmission, but neither of the tested medicines turned out to be effective. The incubation period of the disease is quite long, and even corpses may be contagious. As the largest outbreaks happened in Africa, which is famous for its burial ceremonies, the transmission of the disease from the late people to those who had contact with the bodies spread the infection across several countries (World Organization for Animal Health, 2014).
5. Currently, the biggest pharmaceutical laboratories throughout the world are working on developing effective vaccines against different subtypes of the Ebola viruses. A number of trials have been tested on animals with a little success. The majority of them cannot be applied for human use. Only two vaccines showed successful results in animals and are prepared for being tested in humans at the early critical stage. Those two vaccines are recombinant, and the people, who agreed to test them, are at high risk of getting the disease instead of developing immunity against it. The main goal is to understand what mechanism in the body triggers the process of developing natural anti-bodies capable to tackle the disease.
There are lots of chemotherapeutic efforts made to address the spread of the disease. They all have little success as there is not enough information about the virus. Doctors try to use convalescent plasma, hyperimmune globulin and phosphorus-dominate in order to increase human tolerability of the virus. However, even a little success in the case of animals does not lead to any success in humans. There are some suggestions that nanoparticle that interfere siRNA may stimulate genes to develop immunity regarding the virus. However, such experiments seem futuristic and lack evidence base (World Health Organization, 2014, p. 6). Unless the pathogenesis of the virus is studied in detail, an effective cure cannot be found and tested. Moreover, there is a natural immune protection that may serve as an effective way of helping people, when its mystery is revealed. All other therapies may work well in prevention the spread of disease, but not in saving lives of people who already got sick.
References
Bray, Mike & Chertow, Daniel. (2016). Epidemology and Pathogenesis of Ebola Virus Disease. UpToDate. Retrieved from http://www.uptodate.com/contents/epidemiology-and-pathogenesis-of-ebola-virus-disease
Michalek, P., Krejcova, L., Adam, V. & Kizek, R. (2015). Epidemiology and Pathogenesis of Ebola Virus. Mendelu. Retrieved from http://web2.mendelu.cz/af_239_nanotech/J_Met_Nano/0115/pdf/JMN1-2015-8.pdf
World Health Organization. (2011). Ebola Virus Disease – an Introduction. Retrieved from http://www.searo.who.int/entity/emerging_diseases/ebola/ebola_virus_disease_intro.pdf
World Health Organization. (2014). Potential Ebola Therapies and Vaccines. Retrieved from http://www.who.int/csr/disease/ebola/ebola-new-interventions-02-sep-2014.pdf
World Organization for Animal Health. (2014). Ebola Virus Disease. Retrieved from http://www.oie.int/fileadmin/Home/fr/Media_Center/docs/pdf/Ebola_fact_sheet_EN_Final.pdf
