The Ebola virus is an elongated and filamentous virus, whose length ranges from 800nm to 1000nm. However, its length can extend to 14000nm as a result of concatamerization. The virus has a diameter of 80nm, which is normally uniform. The virus has a helical nucleocapsid, which has a diameter of between 20-30nm and a central axis.
On the outside, the virus is covered by a helical capsid that has a diameter of between 40-50nm and cross-striations measuring 5nm. The viral fragments are polymorphic in nature and can have varying shapes, some taking a “U” shape, a “6” shape, or they can be circular. These fragments are enclosed in a lipid membrane. Each virion always contains a negative-sense genomic viral RNA that is single-stranded.
Transmission
Whenever a new Ebola outbreak occurs, it is believed that the first patient that developed the disease must have had contact with an animal that was infected. Transmission between persons occurs when an uninfected individual has close personal contact with an infected person or body fluids from the affected person. Transmission normally occurs at the late stage of the disease or following the death of the affected individual. The risk of infection is high following handling deceased humans, mainly during funeral preparations.
In a controlled lab setting, exposure of non-human primates to aerosolized ebolavirus isolated from pigs resulted in an infection. However, no evidence has ever been published to show airborne transmission between primates. Viral shedding has also been described in rectal swabs and nasopharyngeal secretions of pigs when the animal was experimentally inoculated.
The disease has an incubation period of between 2-21 days, with an infectious dosage of between 1-10 organisms in non-human primates. In terms of disease communication, the disease can be spread as long as the body fluid, organs, or blood contains the virus. The virus has also been extracted from semen within 61-82 days following the onset of the disease. Transmission via semen has been shown to occur even seven weeks after total recovery from clinical symptoms.
The natural reservoir for the virus is still not known. However, the discovery of antibodies against the virus in the serum samples from wild cats and domestic guinea pigs suggests that these animals could be the reservoirs; however, this has not shown any relationship with the human transmission. Some species of bats are also thought to be natural reservoirs, as viral RNA and antibodies against the virus have been isolated from them.
The advantage of this disease and its mode of transmission is that it can only be transmitted by symptomatic patients. This is helpful because it allows health workers and the public, in general, to identify the affected persons, quarantine them, and handle them with uttermost caution.
This eventually minimizes incidences of new infections and rates of transmission, unlike the spread of diseases that are transmitted by asymptomatic patients, such as HIV/AIDS. The spread of such diseases is very high and difficult to control because the patients cannot be identified.
Signs and Symptoms
The virus enters the cells of the host organisms through the process of endocytosis. After entry into the cell, the virus starts its replication in the cytoplasm of the host cells. The virus impairs the host immune and coagulative blood systems following a successful infection, leading to fatal immunosuppression. The initial signs of the disease are always flu-like and non-specific.
They may include an acute onset of fever, headache, asthenia, myalgia, severe diarrhea, vomiting, abdominal pains, and arthralgia. Other symptoms that are likely to occur, though less often, include bleeding, sore throat, conjunctival injection, and development of rashes. Co-infections, such as cerebral edema, secondary bacterial infection, shock, and coagulative disorders, may occur in the later stages of the infection.
Almost all species of the virus, with the exception of Reston, result in hemorrhagic fever in both non-human primates and humans. These hemorrhagic fever symptoms always set in after 4-5 days following infection.
The symptoms include oral ulceration, pharyngitis, hemorrhagic conjunctivitis, bleeding gums, melena, hematemesis, epistaxis, hematuria, and vaginal bleeding. Other symptoms are likely to occur include marrow suppression, such as leucopenia and thrombocytopenia, hepatocellular damage, proteinuria, and transaminase elevation.
Terminally-ill patients always present with cases of anuria, tachypnea, obtundation, shock, ocular diseases, arthralgia, and normothermic to hypothermia symptoms. Hemorrhagic diathesis is often associated with renal failure, multi-organ failure, nervous system involvement, hepatic damage, and terminal shock.
Physical contact with the virus also results in other symptoms like malaise, acute viral illness, and maculopapular rash. If the infection occurs during pregnancy, the affected mother will always experience copious bleeding, followed by abortion of the fetus. The disease has a fatality rate that ranges between 50 and 100%. Most affected persons die from multisystem failure and hypovolemic shock.
Diagnosis and Treatment
Diagnosis can be either by the use of direct or indirect diagnostic tools, provided the lab is equipped appropriately. Indirect diagnosis involves the detection of antibodies against the virus, rather than the virus itself. Examples of such measures include the use of ELISA techniques to detect antibodies against the Ebola virus and indirect immunofluorescence to detect the anti-Ebola antibodies.
Direct diagnostic methods entail the detection of the actual virus or viral particles. Such methods include the use of RT-PCR to identify the viral RNA, and immuno-electron microscopy to identify the viral particles in the cells of body tissues. However, care should be taken to distinguish between the Ebola virus and Marburg virus because the two are very difficult to distinguish. Great caution should also be taken when handling the samples, as the virus is highly hazardous.
The main treatment strategy for Ebola is the provision of supportive care aimed at maintaining the functions of the body organs, maintaining the electrolyte balance, and combating associated shock, as well as hemorrhage. Up to date, there is no developed vaccine against the virus, with no effective antiviral treatment. There is no known prophylaxis; thus, management of the disease is limited to barrier-nursing and isolation.
Ebola in Texas
The first reported case of Ebola in the US revealed how health systems could make mistakes regarding the disease, which may contribute to its spread. At the Texas Health Presbyterian Hospital, for instance, the medical fraternity did give the condition the seriousness it deserved, despite the knowledge that the patient travelled from Ebola-hit countries.
Two serious mistakes were then committed. First, they allowed the patient to go back to the general public, even after showing Ebola-like symptoms. After indications that the case could be Ebola, they still admitted the patient in general wards, only to isolate the patient two days later. Such mistakes could have resulted in the spread of the condition to other American citizens.
Epidemiology
Currently, the disease is present in West African countries, namely Guinea, Sierra Leone, and Liberia. Other nations that had the disease, but are currently free from the hemorrhagic fever include Nigeria, Mali, Senegal, Spain, United Kingdom, and the United States of America. Normally, a nation is said to be Ebola-free when 42 days (a period that is twice the virus incubation period) pass without any new case of Ebola transmission being reported.
The days are counted from the time when the last patient that was quarantined tested negative for the virus. The US is confident that the Ebola virus will never be experienced in the nation again due to the nation’s improved surveillance programs, better preventive measures, including vigorous screening at the ports of entry, thorough training of medical staffs and public health officers, as well as confidence that a new vaccine against the virus will soon be discovered.
The spread of the disease will be high if the virus undergoes mutation and becomes airborne because even quarantine cannot contain a virus that can be carried around easily by free-flowing air. However, reporting of this possibility by a CNN News reporter is totally irresponsible because the reporter has no single evidence or fact to elaborate this assumption. Also, owing to the large proportion of people reached worldwide through CNN, such information can cause unnecessary anxiety among persons.
Reintegration of Ebola Survivors in the Community
The survivors of Ebola disease are always in fear of rejection and discrimination from the general public. Consequently, it is important for the survivors to undergo constant counseling before they are released back to their homes. There is also the need for the community to be informed thoroughly about the facts of Ebola through established programs to accept the victim back with confidence.
An example of such a program is the one applied by the Firestone District in Liberia. Preparedness is enhanced by teaching the community on the intentions of bringing the survivor back. The community members are also assured of their safety by answering questions from the general public. It also develops the required confidence to help the community fully integrate the victim. In the end, the survivor is welcomed and accepted fully in the community.