Ebola Virus Disease Essay Sample

Introduction

Ebola virus disease (EVD), or commonly known as Ebola, is the most popular fatal illness in the modern times. It is a severe disease caused by a virus which could infect most primates including humans (World Health Organization, 2014). The symptoms or signs of the severe illness could appear from 2 days up to 3 weeks after the virus infection. Patients could suffer from fever, muscle pains, headaches, rash, and vomiting (Gatherer, 2014). Other patients infected with the virus also suffer from internal and external bleeding and their digestive system is damage. The average death rate of the EVD is about 50 percent and they die due to the low blood pressure (Choi & Croyle, 2013).
There are no available treatments or vaccine to control the EVD but there are many potential control systems that the Center for Disease and Control (CDC) has been studying. The CDC together with the international governments is trying to control the outbreaks of EVD through medical services coordination as well as engagement with the community. The EVD was first identified in the two major outbreaks in Nzara and Yambuku. These villages are near with the Ebola River in which the EVD got its name. There have been more than 20 outbreaks in the regions of the Sub-Saharan Africa during 1976 to 2014. The largest outbreak of EVD is ongoing in the West Africa especially in the Sierra Leone and Liberia. In the latest update, there have been about 24,000 cases of EVD which includes almost 950 deaths (World Health Organization, 2014).

Causative Agent

There are 5 known viruses in the genus Ebolavirus but humans could only be infected by 4 which are the Sudan Virus, Tai Forest Virus, Bundibugyo Virus and Ebola Virus or the Zaire Ebola Virus. The Reston Virus or the fifth known virus could not affect humans but it could greatly cause severe illness to most primates. The latest as well as most of the outbreaks in the West Africa is caused by a type of Zaire Ebola Virus. It is the most dangerous virus which already caused thousands of death in Africa. The transmission of the virus could only be done by direct contact with the body fluids or blood of patients diagnosed with EVD (Choi & Croyle, 2013).
The structure of the Ebolavirus is a single strand of RNA genomes which are non-infectious (Baize, 2014). In the structure of the genes that build up the Ebola Virus, there seven genes which includes 3'-UTR-NP-VP35-VP40-GP-VP30-VP24-L-5'-UTR. The five known viruses differ in the sequence of RNA as well as the locations of the overlap between genes (Magill, 2013). The Ebola Viruses appear like filamentous particles which could be coiled, branched and even toroid. The average length of the viruses are about 14, 000 nanometers.
The life cycle of a virion starts when it attach to the host cell and fused to the cell membrane. They are usually trasnmitted through direct contact to humans or thorugh inhalation. In the host cell, they produce the nucleoprotein which switches the gene transcription to gene replication. These genomes accumulate to the cell membrane until they bud off the cell and infect the other cells. The Ebola Virus usually attaches itself to the integrins or C-type Lectins found in the cells. The glycoprotein which is called the GP1,2 is the one which is responsible for the binding ability of the virus as well as its virology. The replication of the virus occurs at the cell membrane and they invade other cells when they are released (Magill, 2013).
The replication of the Ebola virion starts when enter the endosomes of the host cell by macropinocytosis. They attack almost all kinds of cell with DC-SIGN, C-type Lectines or integrins. The virus then releases the ribonucleocapsid in the cytoplasm which starts the sequential transcription of the viral RNAs. Polymerase stuttering is one responsible for the capping and polyadenylation of the viral RNAs in the replication process. They are released to from the host cell when they bud off the plasma membrane and use the matrix proteins to protect them (Magill, 2013).

Epidemiology

Ebola virus was first recognized in 1976 when there are outbreaks in the Zaire. From its discovery up to 2013, there have been a total of 1,716 cases of EVD. However, the largest outbreak of EVD occurs in 2014 which affected large parts of West Africa. The largest outbreak of EVD in March 2014 started in Guinea which quickly spreads to the neighboring countries such as Liberia and Sierra Leone. As of February 28, 2015, there has been over 23,000 patients diagnosed with EVD and over 9,000 confirmed deaths.
The outbreak in the West African Region also affected the economy of the countries near it. There are also some problems with these countries in terms of health care of patients with EVD due to the low quantities of hospitals and personnel. The EVD has also spread outside Africa. There have been 17 cases of EVD from other countries which includes 4 deaths. In October 2014, there have been cases of EVD in the United States (Bustilo et al, 2014). Eric Duncan is confirmed to have died from EVD (Center for Disease Control and Prevention, 2014). He came from Liberia and flew to Texas. He is the source of the virus that infected two health workers which recovered from the severe illness (World Health Organization, 2014).

Clinical Symptoms

The incubation period of the virus in the human body is about 2 to 21 days(Feldman & Geisbert, 2011). However, in most cases the symptoms and signs of EVD appears during 4 to 10 days of exposure to the virus. The major symptoms of EVD includes sudden high fever, sore throat, head ache, muscle pain, tired or weakness and sudden loss of appetite. The Ebola Virus usually affects the digestive system of the patients. The symptoms and signs of EVD are usually followed by diarrhea, vomiting and abnormalities in the liver and kidneys.
In most cases, patients with EVD also suffer from internal and external bleeding. It is due to the low platelet count and abnormalities in the blood clotting. The bleeding usually occurs between 5 to seven days of infection. The internal bleeding is caused by ruptures in the internal organs due to extreme dehydration or diarrhea. It could cause the patient to vomit or to cough blood which is usually the cause of death of the patient(Magill, 2013).
External bleeding usually occurs in the areas of skin which was injected by needles. It could create purpura, hematomas and petechiae(Center for Disease Control and Prevention, 2014). The main cause of death of the patients with EVD is the very low blood pressure. Patients with EVD suffer from low blood pressure due to the loss of fluid. The worst effect of the EVD is the loss of blood due to internal and external bleeding. A patient could recover from EVD but he or she will experience tiredness or weakness for several days. A patient who recovered from the disease will continue to develop antibodies against EVD for about ten years(Gatherer, 2014).

Identification and Diagnosis

When a patient is suspected to have EVD, the most important factor to consider is his or her travel and work history (Choi & Croyle, 2013). The patient’s exposure to wild life is also important since scientists are suspecting that animals not infected by Ebola are the carriers of the virus. Some of the possible non-specific laboratory testing to indicate EVD is the platelet and white blood cell count. The platelet count of the patient with EVD is low while the white blood cell is low initially but it will increase after a few hours or days. Other indicators include high levels of liver enzymes, abnormalities in the internal and external bleeding and prolonged partial thromboplastin time (Baize, 2014).
A person is only diagnosed with EVD when there is confirmed RNA of the virus or detected antibodies which is specific against the virus. The detection of the RNA of the virus is through the polymerase chain reaction. On the other hand, enzyme-linked immunosorbent assay (ELISA) is used to detect the proteins or the antibodies in the human blood for the diagnosis of EVD. In 2015, World Health Organization (WHO) implemented the mobile testing and rapid antigen test in Liberia and other parts of Africa affected by the EVD outbreak in order to detect patients.
The symptoms and signs of the EVD are very similar with the other severe illness such as dengue fever, typhoid, malaria, Marburg virus disease, leptospirosis and others. Differential diagnosis could be done with patients suspecting of EVD although it could be very extensive since there are many severe illness with the same symptoms and signs. Some of the differential diagnosis includes indirect immunofluorescence assay (IFA), Electron Microscopy and Polymerase chain reaction. In the IFA test, the antibodies against Ebola virus is detected when they glow using a compound under the microscope which was lighted by ultraviolet. In the polymerase chain reaction, the genes of the Ebola Virus are amplified for billion folds in order to detect quickly. In the electron microscopy, the Ebola Virus is simply detected since electron microscope is capable of such magnifications (Baize, 2014).

Prevention Strategies

Prevention strategies against EVD usually focus on the stopping outbreaks once a patient is diagnosed. This is because scientists could not identify the main source of the virus during every outbreak. Some scientists believed that the virus is carried by an animal which could not be infected. Prevention of EVD outbreak starts in the laboratory testing and cares with patients. People who work near the patient should wear protective equipment such as mask and gloves. According to the WHO and the CDC, people who works or cares the patients should not leave any skin of their exposed (Baize, 2014).
Patients diagnosed with EVD should be isolated with other people and no authorized person should go near him or her(Feldman & Geisbert, 2011). All the equipment, clothing or any materials which have direct or indirect contact with the patients diagnosed with EVD should be thoroughly disinfected. Isolation means separating the patient who is diagnosed with the severe illness from the others who are not sick. Sometimes, to prevent outbreak, people are put into quarantine. It is a separation of people who have been or suspected to been exposed to disease and release when they did not show any signs or symptoms of the disease.
The CDC also formulated some prevention strategies in order to stop the outbreak or spread of the disease especially to the other countries(Center for Disease Control and Prevention, 2015). The most important part of the prevention is the contact tracing. It is a process of finding all people who have been contacted with a person diagnosed with the disease and separating them to the others for observation as well as preventing the disease to spread(Gatherer, 2014). When a person dies with EVD, they did not allow certain burial rituals. They are finding a way to prevent the virus from spreading to the living people. In the mean time, they are trying to separate all the dead bodies of people who are diagnosed with EVD. However, some of the Africans continue to bury these dead bodies. The CDC are recommending to avoid participating with these burial rituals.

Treatment

As of February 18, 2015, there is no known effective treatment or vaccine to control EVD. There are many candidates as vaccine to prevent the spread of EVD but it needs more time for further research and tests on humans(Baize, 2014). According to CDC, they are developing many studies to understand the mechanism of the virus. In 2014 alone, many candidates for vaccine have been developed to treat and control the EVD but the US Food and Drug Administration did not approve any of it. However, some of the most promising vaccines could cure other primates.
The treatment method for the EVD is usually to support the patient for his or her survival. The most common care treatment for patients diagnosed with EVD is rehydration and symptomatic treatment(Magill, 2013). Rehydration treatment is used to lessen the intensity of the fever, nausea and pain. Some patients are also induced with platelets and red blood cells especially when the patient is suffering from internal or external bleeding. In some places, medications against malaria and other antibiotics is used to support the patient from the illness although it is not proven to treat EVD.
The main problem in the treatment of the EVD is the lack of testing centers and trained personnel in West Africa. This issue is also one of the main reasons why some doctors delay their diagnosis of the EVD which results to the major outbreaks. In 2014, some major tests to quickly diagnose EVD were implemented by the WHO in the West African Region.

Future Outlook

Future outlook for the EVD outbreak in the West African Region could be very difficult since the actual number of cases as well as the geographical extent of the outbreak could not be accurately estimated(World Health Organization, 2014). The worst scenario for the largest outbreak of EVD is the loss of control which could result to the spread of the virus to other parts of Africa as well as the world(Chan, 2014). The WHO as well as the CDC is working with a roadmap to prevent the spread of the EVD to the other parts of Africa. There have been many vaccines and possible medication treatment for the EVD but further human tests should be developed(World Health Organization, 2014).

References:

Baize, S. (2014). Emergence of Zaire Ebola Virus Disease in Guinea. New England Journal of Medicine, 371, 1418-1425
Bustillo, M., Campoy, A., & Mckay, B. (2014). Dallas Ebola Patient Dies. The Wall Street Journal. Retrieved from http://www.wsj.com/articles/dallas-ebola-patient-dies-1412781778?mod=U.S._newsreel_1.
Center for Disease Control and Prevention. (2014). Ebola Viral Disease Outbreak – West Africa, 2014. Retrieved from http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6325a4.htm?s_cid=mm6325a4_w.
Center for Disease Control and Prevention. (2015). What CDC is Doing. Retrieved from http://www.cdc.gov/vhf/ebola/outbreaks/2014-west-africa/what-cdc-is-doing.html.
Center for Disease Control and Prevention. (2014). Ebola Hemorrhagic Fever Prevention. Retrieved from http://www.cdc.gov/vhf/ebola/prevention/index.html.
Chan, M. (2014). Ebola Virus Disease in West Africa: no Early end to the Outbreak. Journal of Medicine (371), 1183-1185
Choi, J., & Croyle, M. (2013). Emerging Targets and Novel Approaches to Ebola Virus prophylaxis and treatment. Biological Drugs, 27(6), 565-583
Feldman, H., & Geisbert, T. (2011). Ebola Haemorrhagic Fever. Lancet 337, 849-862.
Gatherer, D. (2014). The 2014 Ebola Virus Disease Outbreak in West Africa. Journal of General Virology, 95(8), 1619-1624
Magill, A. (2013). Hunter's tropical medicine and emerging infectious diseases. 9th ed. New York: Saunders.
World Health Organization. (2014). Ebola Response Roadmap: Situation Report. Retrieved from http://apps.who.int/iris/bitstream/10665/145198/1/roadmapsitrep_10Dec2014_eng.pdf?ua=1.
World Health Organization. (2014). Ebola Virus Disease. Retrieved from http://www.who.int/mediacentre/factsheets/fs103/en/.