Issues with The Ebola Virus Disease - Report Example

EBOLA VIRUS DISEASE Ebola Virus Disease The Ebola Virus Disease, also known as Viral Haemorrhagic fever, is a disease that has recently been known for its fatality rates as well as its rapid spread. Caused by a variety of viruses, the spread of this disease has been accredited to the Ebola Virus, one of the Filoviridae, with its exhibition in the form of circulatory impairment, increased vascular permeability and widespread haemorrhage (Parija, 2014). The first incidences of this disease were reported in 1976 by two places in Africa simultaneously: Nzara in Sudan and Yambuku in Democratic Republic of Congo. The virus derives its name from the Ebola River in Congo(Who.int, 2014). Since then the virus has spread to several countries in Africa as well as elsewhere in the world, and the World Health Organisation (WHO) with its case fatality being fifty percent average(Who.int, 2014). It is currently one of the most fatal diseases (if untreated) in the world and has the WHO, Centers of Disease Control and prevention (CDC) and the government of various countries alert and on the lookout. Causative Agent: Ebola Virus Ebola virus is one of the Filoviridae. The Filoviridae are a part of the order Mononegavirales. Mononegavirales is a group of viruses which comprises of non-segmented, negative sense (NNS) RNA genomes, covered by an envelope (Mahy et al., 2010). The Filoviridae are further divided into two genera: Marburg virus and Ebola virus. Ebola virus is further divided into four species based on the region of incidences, namely: Zaire Ebola virus, Sudan Ebola virus, Cote d Ivoire Ebola virus and Reston Ebola virus(Mahy et al., 2010). Due to the absence of vaccination and chemotherapy of these viral infections as well as their transmission between two people due to human contact, possible spread of infections via aerosol and subsequent increase in mortality rate, the Filoviridae have been classified as agents of maximum containment (biosafety level 4) and category A pathogens (Mahy et al., 2010). With the exception of Reston virus and Lloviu virus (a type of Cuevavirus, all the species of Filoviridae cause Viral haemorrhagic fever(Singh & Ruzek, 2014). The structure of all Filoviridae comprises of enveloped, non-segmented, negative strand RNA. The envelope that covers the Filoviridae is composed of a lipid membrane that stems from that of the host cell plasma membrane. Thus, the consistency of this covering resembles the lipid and protein composition of the cell that the filovirus has infected (Mahy et al., 2010). Morphologically, the Filoviridae resemble a thread and are known to be filamentous and contain pleomorphic structures such as straight tube-like structures, branching arrangements, curved or ‘U’ shaped structures or curved filaments with the shape of the number six (6) (Mahy et al., 2010). The Ebola virus has the length of around 1000 nanometre (Mahy et al., 2010). The viral structure is composed of multiple proteins, of which the glycoprotein type I protein is composed of two subunits. It is this very glycoprotein that causes the attachment, receptor-mediated endocytosis, the combination with the endocytosed vesicle and subsequent release of the core of virus into the vesicle (May et al., 2010).In the structure of Ebola virus glycoprotein, there are several genes that overlap. Most of the genes that encode for the glycoprotein are non-coding sequences at 3’ and 5’ ends. These genes contain signals for replication and encapsidation (Liu, 2014). The mechanism of transmission of Ebola virus to the first incidence is unknown as the natural reservoir of Ebola virus host has not been discovered until yet. However, once inside the human system, it can be transmitted from person to person via broken skin, or mucous membrane by way of blood or the body fluids such as urine, sweat, saliva, faeces, vomit, breast milk, and semen of a person who suffers from Ebola. Penetrating objects such as needles that are infected with Ebola virus can also transmit the infection. It has been postulated by researchers that Ebola virus can also be transmitted through animals. Up until now, water or airborne droplets or mosquito have shown no signs of carrying Ebola virus. However, in Africa wild animals and mammals such as bats are known to carry the virus. (Wilson, 2014). People in close proximity to those carrying Ebola virus or its infections are most likely to acquire it, such as family, close friends or healthcare persona who are taking care of them thus the requirement of a quarantine or protective gear such as masks, gloves etcetera are essential (Wilson, 2014). Epidemiology Ebola virus was first noticed in Democratic Republic of Congo (then known as Zaire) near the Ebola River and was therefore named as such. Since then outbreaks have occurred in Sudan and rural areas of Central Africa, sometimes being so lethal that it kills the entire population before spreading any further (Murray et al., 2009). It is interesting to note that few of the Africans have been found with antibodies to the virus, which indicates that there may have been sub-clinical infections which did not show classical symptoms (Murray et al., 2009). Ebola Virus Disease has, since its outbreak occurred in Democratic Republic of Congo five times (1977, 1995, 2007, 2008, 2012), in Sudan (1979, 2004), in Gabon (1994, 1996, 2001, 2002), Uganda (2000, 2007, 2011, 2012), Republic of the Congo (2001, 2002, 2003, 2005), Guinea, Liberia, Sierra Leone and Nigeria in 2014 (World Health Organisation, 2014). It occurred in Nigeria after the traveller infected from Liberia entered the country. It is the recent outbreak of Ebola Virus that is in need for urgent diagnosis and treatment as the incidences are becoming drastically common. Clinical Symptoms The Ebola virus disease is exhibited by fever, headache, pain in the neck, conjunctival inflammation and diarrhoea along with involvement of the liver, kidneys as well as the CNS and ultimately, due to coagulation disorders by its consuming effect, it results in excessive haemorrhage, culminating in shock. As far as pathologies are considered from an anatomical point of view, almost all organs are haemorrhaged and have fibrin deposits (Kayser, 2005). Laboratory Diagnosis Several of the symptoms that the Ebola virus disease causes are similar to other conditions such as malaria, therefore in order to differentiate between these two several diagnostic tools are adopted. Viral Haemorrhagic Fevers undergo immunodiagnostic tests such as antibody captured - enzyme-linked immunosorbent assay (ELISA) and antigen-capture detecting tests (Who.int, 2014) are done in order to detect antibodies against Ebola virus. Molecular diagnostic evaluations such as reverse transcriptase – polymerase chain reaction (RT-PCR) assay (Who.int, 2014) and cell culture or electron microscopy (due to their small size) are also done in order for Ebola virus disease to be diagnosed. Studying such fevers for research and therapeutic purposes poses extreme biological hazards and therefore should only be conducted in facilities which contain biosafety level 4 (BSL-4) (Engelkirk & Duben-Engelkirk, 2008). In order to determine the pathogenicity of the Ebola virus, the cell culture techniques in Ebola virus involve culture from the mammalian cells explained further. Virus isolation of the Ebola virus requires the containment of BSL-4 as well as the proper handling of the sample due to increased risk of lethal infection. The virus can be isolated from the blood during the acute phase of the disease by administering Rhesus Monkey kidney cells as well as carcinoma cells. Identification of these is then done by ELISA and immunofluorescence assays (Munir, 2013). It is important to conduct these tests during acute phase only as animals do not cause this because then antibody response starts to occur. Due to its size in nanometres (ranging from 800-1400 nanometres), Ebola virus is viewed in a microscope. The earlier techniques of CCHF for culture of Ebola Virus has been replaced by RT-PCR assays by neutralizing nucleic acid and is beneficial due to the fact that a large amount of sample is not required for diagnosis (Mahy et al., 2010).Several monoclonal and polyclonal antibodies are also being used to detect the antigen antibodies against Ebola virus or recombinant proteins that have been formed against the glycoprotein-I (Munir, 2013). The latest techniques such as RT-PCR have enhanced the ease of diagnosis of this disease. Rational vaccine design aims to evaluate whether pathogen-specific memory cells can be triggered in order to generate a vaccine. This mathematical acquisition has the purpose of culminating in the T-cell proliferation which would lead to protection against the virus (Banton et al., 2010). The future effect of such researches could ultimately lead to a functional vaccine and thus protection against the lethal disease. Prevention strategies According to the World Health Organisation, the incidence of Ebola virus disease is greater among bats and monkeys. Therefore in the recent years, they have devised prevention strategies which consist of the steps: preparing before the epidemic arises; alerting themselves by detecting Ebola virus, investigating any important cases and estimating the risks involved in the spread of disease; response in the events of an outbreak as well as action to contain the patients, and ultimately the evaluation after an epidemic has arisen (World Health Organisation, 2014). The pre-epidemic phase of this strategy involves the restriction of any people coming in contact with body fluids such as blood, urine etcetera as well as regular monitoring of any mammals. During the alert and epidemic phase of the disease, it is essential to call for a group who can set up surveillance system set up, mobilization of the relatives of the patient suffering from Ebola virus disease, clinical treatment of the patients and practiced precaution by healthcare personnel. After the epidemic phase, the team should evaluate the incidence and mortality rate, as well as add it to the general number of incidences that have occurred every year in a particular place, and devise other strategies to keep people away from the Ebola virus(World Health Organisation, 2014). The reduction of risk of the Ebola virus from occurring include reducing the risk of transmission by limiting contact with wild monkeys or apes and all animals should be handled with gloves. Animal meat should be cooked and hand washing given primary importance to. It can also be prevented by safe burial methods (WHO.int, 2014). Treatment Symptomatic treatment is usually effective in improving the chances of survival in the Ebola virus disease. Rehydration along with oral fluids or fluids administered intravenous fluids essential. No treatment has been proven to be beneficial to Ebola virus disease. Yet, potential treatments such as blood products, immune therapies and drug therapies are being evaluated (WHO.int, 2014). It is important to notice that the acute onset of disease, if not severe can be promptly diagnosed and treated as most of it is self-limiting. The treatment stops once the symptoms disappear. Future Outlook The recent outbreak of Ebola virus disease in West Africa has generated a wave of support from all around the world. CDC reports a dramatic slowing of the incidence of Ebola virus disease in Liberia, but continues to battle it in Sierra Leone (Centers of Disease Control and Prevention, 2014). The WHO is also trying to prevent Ebola outbreaks by continuing surveillance for Ebola virus disease and assisting countries that are at risk to develop plans in order to prevent the disease from occurring (World Health Organisation, 2014). Moreover, clinical trials are taking place in order to formulate a working treatment for the Ebola virus disease in the form of ‘ZMapp’, in alliance with the National Institutes of Health (CDC, 2014). Thus with the fervent help of all the countries in order to combat Ebola incidences in the world, it is possible that the disease would decrease to a large extent, if not completely vanish off the face of the earth. In conclusion, lethal viral diseases such as the Ebola virus disease that is transmitted through mammals and person to person contact need to be rapidly eliminated in order to result in a healthier society. This is because even though it is rare in developed countries, there always lies an underlying risk in migrating people bringing in the disease, thus the healthcare system of all countries need to be well armed with the aforementioned techniques for prevention, diagnosis, treatment and evaluation to deal with the disease promptly. Bibliography BANTON, S., ROTH, Z., & PAVLOVIC, M. (2010). Mathematical Modelling of Ebola Virus Dynamics as a Step towards Rational Vaccine Design. Centers for Disease Control and Prevention (2014). Ebola epidemic continues to spread, requiring intensified effort | CDC Online Newsroom | CDC. [online] Cdc.gov. Available at: http://www.cdc.gov/media/releases/2014/p1222-ebola-response.html [Accessed 27 Dec. 2014]. ENGELKIRK, P. G., & DUBEN-ENGELKIRK, J. L. (2008). Laboratory diagnosis of infectious diseases: essentials of diagnostic microbiology. Baltimore, Wolters Kluwer Health/Lippincott Williams & Wilkins. KAYSER, F. H. (2005). Medical microbiology. Stuttgart, Georg Thieme Verlag. LIU, D. (2014). Manual of security sensitive microbes and toxins. Boca Raton, CRC Press, Taylor and Francis. http://dx.doi.org/10.1201/b16752. MAHY, B. W. J., & VAN REGENMORTEL, M. H. V. (2010). Desk encyclopaedia of human and medical virology. Oxford, Academic. MUNIR, M. (2013). Mononegaviruses of veterinary importance. Volume 1, volume 1. MURRAY, P. R., ROSENTHAL, K. S., & PFALLER, M. A. (2009). Medical microbiology. Philadelphia, Mosby/Elsevier. PARIJA, S. C. (2014). Textbook of Microbiology & Immunology. London, Elsevier Health Sciences APAC. SINGH, S. K., & RUZEK, D. (2014). Viral haemorrhagic fevers. Boca Raton, CRC Press, Taylor & Francis Group. Who.int, (2014). WHO | Ebola virus disease, West Africa – update. [Online]. World Health Organization. Available at: http://www.who.int/csr/don/2014_07_31_ebola/en/ [Accessed 27 Dec. 2014]. WILSON, F. (2014). CDC guidance on Ebola virus disease (EVD). New York : International Publications Media Group. WORLD HEALTH ORGANIZATION. (2014). Ebola and Marburg virus disease epidemics: preparedness, alert, control, and evaluation. WHO Press, World Health Organization. Available at: http://www.who.int/csr/disease/ebola/PACE_outbreaks_ebola_marburg_en.pdf [Accessed 27 Dec. 2014]. Read More