what can you tell me about the structure of an ebola virus. Like what size is the actual virus? If you don't know this, can you please send me a link for a website on this? I haven't found one except Wikipedia but that isn't always a reliable source.
Thanks! E路bo路la virus (沫-b艒'l蓹, 臅b'艒-l盲 )
n.
An extremely contagious filovirus causing an acute, usually fatal hemorrhagic fever and spread through contact with bodily fluids of infected persons and by airborne particles.
[After the Ebola River in northwest Democratic Republic of the Congo, where the disease was first observed.]
Ebola Virus
Ebola Virus available. Ebola Virus. Shop now!
www.eBay.com
Ebola Information
Learn about Ebola, including the statistics and history.
www.HealthPolitics.org
Science and Technology Encyclopedia Library > Science > Science and Technology Encyclopedia Ebola virus
Ebola viruses are a group of exotic viral agents that cause a severe hemorrhagic fever disease in humans and other primates. The four known subtypes or species of Ebola viruses are Zaire, Sudan, Reston, and C么te d'Ivoire (Ivory Coast), named for the geographic locations where these viruses were first determined to cause outbreaks of disease. Ebola viruses are very closely related to, but distinct from, Marburg viruses. Collectively, these pathogenic agents make up a family of viruses known as the Filoviridae.
Filoviruses have an unusual morphology, with the virus particle, or virion, appearing as long thin rods. A filovirus virion is composed of a single species of ribonucleic acid (RNA) molecule that is bound together with special viral proteins, and this RNA鈥損rotein complex is surrounded by a membrane derived from the outer membrane of infected cells. Infectious virions are formed when the virus buds from the surface of infected cells and is released. Spiked structures on the surface of virions project from the virion and serve to recognize and attach to specific receptor molecules on the surface of susceptible cells, allowing the virion to penetrate the cell. The genetic information contained in the RNA molecule directs production of new virus particles by using the cellular machinery to drive synthesis of new viral proteins and RNA. See also Ribonucleic acid (RNA); Virus.
Although much is known about the agents of Ebola hemorrhagic fever disease, the ecology of Ebola viruses remains a mystery. The natural hosts of filoviruses remain unknown, and there has been little progress at unraveling the events leading to outbreaks or identifying sources of filoviruses in the wild. Fortunately, the incidence of human disease is relatively rare and has been limited to persons living in equatorial Africa or working with the infectious viruses. The virus is spread primarily through close contact with the body of an infected individual, his or her body fluids, or some other source of infectious material.
Ebola virus hemorrhagic fever disease in humans begins with an incubation period of 4鈥?0 days, which is followed by abrupt onset of illness. Fever, headache, weakness, and other flulike symptoms lead to a rapid deterioration in the condition of the individual. In severe cases, bleeding and the appearance of small red spots or rashes over the body indicate that the disease has affected the integrity of the circulatory system. Individuals with Ebola virus die as a result of a shock syndrome that usually occurs 6鈥? days after the onset of symptoms. This shock is due to the inability to control vascular functions and the massive injury to body tissues.
It appears that the immune response is impaired and that a strong cellular immune response is key to surviving infections. This immunosuppression may also be a factor in death, especially if secondary infections by normal bacterial flora ensue. See also Immunosuppression.
Outbreaks of Ebola virus disease in humans are controlled by the identification and isolation of infected individuals, implementation of barrier nursing techniques, and rapid disinfection of contaminated material. Diagnosis of Ebola virus cases is made by detecting virus proteins or RNA in blood or tissue specimens, or by detecting antibodies to the virus in the blood.
Dilute hypochlorite solutions (bleach), 3% phenolic solutions, or simple detergents (laundry or dish soap) can be used to destroy infectious virions. No known drugs have been shown to be effective in treating Ebola virus (or Marburg virus) infections, and protective vaccines against filoviruses have not been developed.
--------------------------------------...
Ebola Virus Pictures
Professional medical illustrations and articles for medical issues.
Healthline.com
Medical Term Library > Health > Medical Analysis Ebola virus
A notoriously deadly virus that causes fearsome symptoms, the most prominent being high fever and massive internal bleeding. Ebola virus kills as many as 90% of the people it infects. It is one of the viruses that is capable of causing hemorrhagic (bloody) fever.
Epidemics of Ebola virus have occurred mainly inAfrican countries including Zaire (now the DemocraticRepublic of Congo), Gabon, Uganda, the Ivory Coast, and Sudan. Ebola virus is a hazard to laboratory workers and, for that matter, anyone who is exposed to it.
Infection with Ebola virus in humans is incidental -- humans do not "carry" the virus. The way in which the virus first appears in a human at the start of an outbreak has not been determined. However, it has been hypothesized that the first patient (the index case) becomes infected through contact with an infected animal.
Ebola virus is transmitted by contact with blood, feces or body fluids from an infected person or by direct contact with the virus, as in a laboratory. People can be exposed to Ebola virus from direct contact with the blood or secretions of an infected person. This is why the virus has often been spread through the families and friends of infected persons: in the course of feeding, holding, or otherwise caring for them, family members and friends would come into close contact with such secretions. People can also be exposed to Ebola virus through contact with objects, such as needles, that have been contaminated with infected secretions.
The incubation period --the period between contact with the virus and the appearance of symptoms -- ranges from 2 to 21 days.
The initial symptoms are usually high fever, headache, muscle aches, stomach pain, and diarrhea. There may also be sore throat, hiccups, and red and itchy eyes. The symptoms that tend to follow include vomiting and rash and bleeding problems with bloody nose (epistaxis), spitting up blood from the lungs (hemoptysis) and vomiting it up from the stomach (hematemesis), and bloody eyes (conjunctival hemorrhages). Then finally come chest pain, shock, and death.
A protein on the surface of the virus has been discovered that is responsible for the severe internal bleeding (the death-dealing feature of the disease). The protein attacks and destroys the endothelial cells lining blood vessels, causing the vessels to leak and bleed.
There is no specific treatment for the disease. Currently, patients receive supportive therapy. This consists of balancing the patient's fluids and electrolytes, maintaining their oxygen level and blood pressure, and treating them for any complicating infections. Death can occur within 10 days of the onset of symptoms.
Related Links on MedicineNet.com
Page 2 of this Article
Disclaimer: Information on this web site is provided for informational purposes only and is not a substitute for professional medical advice. You should not use the information on this web site for diagnosing or treating a medical or health condition. You should carefully read all product packaging. If you have or suspect you have a medical problem, promptly contact your professional healthcare provider.
Statements and information regarding dietary supplements have not been evaluated or approved by the Food and Drug Administration. Please consult your healthcare provider before beginning any course of supplementation or treatment.
Britannica Library > Reference > Britannica Concise Ebola
Virus responsible for a severe and often fatal hemorrhagic fever. Outbreaks in primates, including humans, have been recorded. Initial symptoms are fever, severe headaches and muscle aches, and loss of appetite; blood clots and profuse uncontrollable hemorrhaging appear within days, followed by nausea, vomiting, and diarrhea. Death occurs in 8 鈥?17 days; fatality rates range from 50% to 90%. There is no known treatment. It takes its name from the Ebola River in northern Congo (Zaire), where it first emerged in 1976. The virus appears as long filaments, sometimes branched or intertwined. The virus particle contains one molecule of RNA. How it attacks cells is unknown. It can be transmitted through contact with bodily fluids; unsanitary conditions and lack of adequate medical supplies have been factors in its spread.
For more information on Ebola, visit Britannica.com.
--------------------------------------...
Encyclopedia Library > Reference > Encyclopedia Ebola virus (膿b艒'l蓹) , a member of a family (Filovirus) of viruses that cause hemorrhagic fevers. The virus, named for the region in Congo (Kinshasa) where it was first identified in 1976, emerged from the rain forest, where it survives in as yet unconfirmed hosts, possibly several species of fruit bats. The virus can be fatal to chimpanzees and gorillas as well as humans.
Three strains of the virus, which are found in Africa, cause hemorrhagic fever; the fourth, found in the W Pacific, does not. Once a person is infected with the virus, the disease has an incubation period of 2鈥?1 days; however, some infected persons are asymptomatic. Initial symptoms are sudden malaise, headache, and muscle pain, progressing to high fever, vomiting, severe hemorrhaging (internally and out of the eyes and mouth) and in 50%鈥?0% of patients, death, usually within days. The likelihood of death is governed by the virulence of the particular Ebola strain involved. Ebola virus is transmitted in body fluids and secretions; there is no evidence of transmission by casual contact. There is no vaccine and no cure.
Outbreaks of Ebola virus in humans occurred in both Congo-Kinshasa (then Za茂re) and Sudan in 1976 and 1979; other outbreaks have occurred since in Gabon, Uganda, and both Congos. Outbreaks have been exacerbated by underequipped hospitals that reused syringes and lacked proper protective clothing for personnel. In 1989 a similar virus was found in monkeys imported to the United States.
--------------------------------------...
Encyclopedia of Intelligence Library > Reference > Encyclopedia of Intelligence Ebola Virus Related Topics
Biological Warfare
Biological Weapons, Genetic Identification
Bioshield Project
Bioterrorism
Cdc (United States Centers for Disease Control and Prevention)
Hemorrhagic Fevers and Diseases
Viral Biology
The Ebola virus is one of two members of a family of viruses that is designated as the Filoviridae. The name of the virus comes from a river located in the Democratic Republic of the Congo, where the virus was discovered. Although naturally occurring, some public health experts worry that the lethality of the virus makes it an attractive potential bioterrorism agent. Under natural circumstances Ebola induced hemorrhagic fever carriers have such high death rates that their rapid death actually acts to limit the spread of the virus. Deliberate spread of the virus would counteract this natural limiting factor.
The species of Ebola virus are among a number of viruses that cause a disease, hemorrhagic fever, that is typified by copious internal bleeding and bleeding from various orifices of the body, including the eyes. The disease can be swiftly devastating and results in death in over 90 per cent of cases.
To date, four species of Ebola virus have been identified, based on differences in their genetic sequences and in the immune reaction they elicit in infected individuals. Three of the species cause disease in humans. These are Ebola-Zaire (isolated in 1976), Ebola-Sudan (also isolated in 1976), and Ebola-Ivory Coast (isolated in 1994). The fourth species, called Ebola-Reston, causes disease in primates. The latter species is capable of infecting humans but so far has not caused disease in humans. Ebola-Reston is named for the United States military primate research facility where the virus was isolated, during a 1989 outbreak of the disease caused by infected monkeys that had been imported from the Philippines. Until the non-human involvement of the disease was proven, the outbreak was thought to be the first outside of Africa.
The appearance of the Ebola virus only dates back to 1976. The explosive onset of the illness and the underdeveloped and wild nature of the African region of the virus's appearance have complicated the definitive determinations of the origin and natural habitat of Ebola. The source of the Ebola virus is still unknown. However, given that filovirus, which produce similar effects, establish a latent infection in African monkeys, macaques, and chimpanzees, scientists consider the possibility that the Ebola virus likewise normally resides in an animal that lives in Africa. A search for Ebola virus in such primates has so far not revealed evidence of the virus.
Almost all confirmed cases of Ebola from 1976 to 2002 have been in Africa. In the latest outbreak, which has been ongoing since late in 2001, 54 people have died in the Gabon as of February of 2002. In the past, one individual in Liberia presented immunological evidence of exposure to Ebola, but had no symptoms. As well, a laboratory worker in England developed Ebola fever as a result of a laboratory accident in which the worker was punctured by an Ebola-containing needle.
The Ebola virus produces a high fever, headache, muscle aches, abdominal pain, tiredness and diarrhea within a few days after infecting a person. Some people will also display bloody diarrhea and vomit blood. At this stage of the disease some people recover. But, for most of those who are infected, the disease progresses within days to produce copious internal bleeding, shock and death.
Outbreaks of infection with the Ebola virus appear sporadically and suddenly. The outbreak rapidly moves through the local population and often just as quickly ends. The initial infection is presumable by contact between the person and the animal that harbors the virus. Subsequent person-to-person spread likely occurs by contamination with the infected blood or body tissues of an infected person in the home or hospital setting, or via contaminated needles. The fact that infected people tend to be in more under-developed regions, where even the health care facilities are not as likely to be equipped with isolation wards, furthers the risk of spread. The person-to-person passage is immediate; unlike the animal host, people do not harbor the virus for lengthy periods of time.
The possibility of air-borne transmission of the virus is debatable. Ebola-Reston may well have been transmitted from monkey to monkey in the Reston military facility via the air distribution system, since some of the monkeys that were infected were never in physical contact with the other infected monkeys. However, if the other species of the virus are capable of similar transmission, this has not yet been documented. Laboratory studies have shown that Ebola virus can remain infectious when aerosolized. But the current consensus is that airborne transmission is possible but plays a minor role in the spread of the virus.
In the intervening years between the sporadic outbreaks, the Ebola virus probably is resident in the natural reservoir.
Currently there is no cure for the infection caused by the Ebola virus. However, near the end of an outbreak of the virus in 1995 in Kikwit, Africa, blood products from survivors of the infection were transfused into those actively experiencing the disease. Of those eight people who received the blood, only one person died. Whether or not the transfused blood conveyed protective factor was not ascertained. A detailed examination of this possibility awaits another outbreak.
The molecular basis for the establishment of an infection by the Ebola virus is still also more in the realm of proposal than fact. One clue has been the finding of a glycoprotein that is a shortened version of the viral constituent in the in the circulating fluid of humans and monkeys. This protein has been suggested to function as a decoy for the immune system, diverting the immune defenses from the actual site of viral infection. Another immunosuppressive mechanism may be the selective invasion and damage of the spleen and the lymph nodes, which are vital in the functioning of the immune system.
The devastating infection caused by the Ebola virus is all the more remarkable given the very small size of the viral genome, or complement of genetic material. Fewer than a dozen genes have been detected. How the virus establishes an infection and evades the host immune system with only the capacity to code for less than twelve proteins is unknown.
Further Reading
Books
Cormican, M. G. and M. A. Pfaller. "Molecular Pathology of Infectious Diseases," in Clinical Diagnosis and Management by Laboratory Methods, 20th ed. Philadelphia: W. B. Saunders, 2001.
Periodicals
Peters, C. J., and J. W. LeDuc. "An Introduction to Ebola: The Virus and the Disease." The Journal of Infectious Diseases no. 179 (Supplement 1, February 1999): ix鈥搙vi.
Electronic
Centers for Disease Control. "Ebola Hemorrhagic Fever." 2001. <>http://www.cdc.gov/ncidod/dvrd/spb/mnpag... (March 12, 2003).
鈥斺€? "Viral Hemorrhagic Fevers." 2000. <>http://www.cdc.gov/ncidod/dvrd/spb/mnpag... (March 12, 2003).
Health Library > Health > Health Ebola (i-boh-luh)
A highly lethal virus that causes massive internal hemorrhaging. It is thought that the virus originated in central Africa and was passed to humans from primates.
This virus has been responsible for a greatly increased interest in and vigilance over new, exotic infectious diseases that are at risk of spreading rapidly, given the nature of modern jet transportation and bioterrorism.
Medical Library > Health > Medical Dictionary Eb路o路la virus (臅b'蓹-l蓹)
n.
An RNA virus that causes acute, highly fatal hemorrhagic fever that spreads through contact with bodily fluids or secretions of infected persons.
WordNet Library > Reference > WordNet Note: click on a word meaning below to see its connections and related words.
The noun ebola virus has one meaning:
Meaning #1: a virus that causes viral hemorrhagic fever
--------------------------------------...
Wikipedia Library > Reference > Wikipedia Ebola
<imagemap>Image:Information-silk.png|H... to read a taxobox
rect 0 0 50 50 desc none</imagemap>Ebola virus
Virus classification
Group: Group V ((-)ssRNA)
Order: Mononegavirales
Family: Filoviridae
Genus: Ebolavirus
Species: Reston Ebolavirus
Sudan Ebolavirus
Ivory Coast Ebolavirus
Za茂re Ebolavirus
Ebola
Classification & external resources ICD-10 A98.4
ICD-9 065.8
DiseasesDB 18043
MedlinePlus 001339 000000
eMedicine med/626
MeSH C02.782.417.415
Ebola is the common term for a group of viruses belonging to genus Ebolavirus, family Filoviridae, which cause Ebola hemorrhagic fever.[1] The disease can be deadly and encompasses a range of symptoms including vomiting, diarrhea, changes in skin color, general body pain, internal and external bleeding, and fever.[2] Mortality rates are generally high, ranging from 50% - 90%,[3] with the cause of death usually due to hypovolemic shock or Multiple organ dysfunction syndrome.[4]
The virus is named after the Ebola River in the African nation-state of the Democratic Republic of the Congo (formerly Za茂re), near the site of the first outbreaks.[5] The Democratic Republic of Congo has been the site of four recent outbreaks, including one in May 2005.
Ebola is believed to be a zoonotic virus, although despite considerable effort by the World Health Organization, no animal reservoir capable of sustaining the virus between outbreaks has been identified. One possible candidate reservoir is the fruit bat[6]; another is the dog. [7]
Because Ebola is lethal and since no approved vaccine or treatment is available, Ebola is classified as a Biosafety Level 4 agent, as well as a Category A Bioterrorism agent[8] and a select agent by the CDC.
The symptoms of Ebola are rather similar to that of the Marburg virus, which is also in the family Filoviridae.
Structure
Electron micrograph of the filamentous structure of Ebola
Size and shape
Electron micrographs of members of Ebolavirus show them to have the characteristic thread-like structure of a filovirus. The virions are variable in shape and may appear as a "U", "6", coiled, circular, or branched shape, however, laboratory purification techniques, such as centrifugation, may contribute to the various shapes seen. Virions are generally 80nm in diameter. They are variable in length, and can be up to 1400 nm long. On average however, the length of a typical Ebola virus is closer to 1000 nm. In the center of the virion is a structure called nucleocapsid, which is formed by the helically wound viral genomic RNA complexed with the proteins NP, VP35, VP30 and L. It has a diameter of 40 鈥?50 nm and contains a central channel of 20 鈥?30 nm in diameter. Virally encoded glycoprotein (GP) spikes 10 nm long and 10 nm apart are present on the outer viral envelope of the virion, which is derived from the host cell membrane. Between envelope and nucleocapsid, in the so called matrix space, the viral proteins VP40 and VP24 are located.
Genome
Each virion contains one molecule of linear, single-stranded, negative-sense RNA, totalling 18900 nucleotides in length. The 3鈥?terminus is not polyadenylated and the 5鈥?end is not capped. It codes for seven structural proteins and one non-structural protein. The gene order is 3鈥?- leader - NP - VP35 - VP40 - GP/sGP - VP30 - VP24 - L - trailer - 5鈥? with the leader and trailer being non-transcribed regions which carry important signals to control transcription, replication and packaging of the viral genome into new virions. The genomic material by itself is not infectious, because viral proteins, among them the RNA-dependent RNA polymerase, are necessary to transcribe the viral genome into mRNAs, as well as for replication of the viral genome.
Species
Za茂re Ebolavirus
The Za茂re Ebolavirus has the highest mortality rate, up to 90% in some epidemics, with an average of approximately 83% mortality over 27 years. The case-fatality rates were 88% in 1976, 100% in 1977, 59% in 1994, 81% in 1995, 73% in 1996, 80% in 2001-2002 and 90% in 2003. There have been more outbreaks of Za茂re Ebolavirus than any other strain.
The first outbreak took place on August 26, 1976 in Yambuku, a town in the north of Za茂re. The first recorded case was Mabalo Lokela, a 44-year-old schoolteacher returning from a trip around the north of the state. His high fever was diagnosed as possible malaria and he was subsequently given a quinine shot. Lokela returned to the hospital every day. A week later, his symptoms included uncontrolled vomiting, bloody diarrhea, headache, dizziness, and trouble breathing. Later, he began bleeding from his nose, mouth, and rectum. Mabalo Lokela died on September 8, 1976, roughly 14 days after the onset of symptoms.
Known human cases and deaths during outbreaks of Za茂re Ebolavirus between 1976 and 2003Soon after, more patients arrived with varying but similar symptoms including fever, headache, muscle and joint aches, fatigue, nausea and dizziness. These often progressed to bloody diarrhea, severe vomiting, and bleeding from the nose, mouth, and rectum. The initial transmission was believed to be due to reuse of the needle for Lokela鈥檚 injection without sterilization. Subsequent transmission was also due to care of the sick patients without barrier nursing and the traditional burial preparation method, which involved washing and gastrointestinal tract cleansing.
Sudan Ebolavirus
Sudan Ebolavirus was the second strand of Ebola reported in 1976. It apparently originated amongst cotton factory workers in Nzara, Sudan. The first case reported was a worker exposed to a potential natural reservoir at the cotton factory. Scientists tested all animals and insects in response to this, however none tested positive for the virus. The carrier is still unknown.
A second case involved a nightclub owner in Nzara, Sudan. The local hospital, Maridi, tested and attempted to treat the patient; however, nothing was successful, and he died. The nurses did not apply safe and practical procedures in sterilizing and disinfecting the medical tools used on the nightclub owner, facilitating the spread of the virus in the hospital.
The most recent outbreak of Sudan Ebolavirus occurred in May 2004. As of May 2004, 20 cases of Sudan Ebolavirus were reported in Yambio County, Sudan, with 5 deaths resulting. The Centers for Disease Control and Prevention confirmed the virus a few days later. The neighbouring countries of Uganda and the Democratic Republic of Congo have increased surveillance in bordering areas, and other similar measures have been taken to control the outbreak. The average fatality rates for Sudan Ebolavirus were 53% in 1976, 68% in 1979, and 53% in 2000/2001. The average case-fatality rate is 53.76%.
Known human cases and deaths during outbreaks of Sudan Ebolavirus between 1976 and 2003
Reston Ebolavirus
Main article: Ebola Reston
First discovered in November of 1989 in a group of 100 Crab-eating monkeys (Macaca fascicularis) imported from the Philippines to Reston, Virginia. A parallel infected shipment was also sent to Philadelphia. This strain was highly lethal in monkeys, but did not cause any fatalities in humans. Six of the Reston primate handlers tested positive for the virus, two due to previous exposure.
Further Reston Ebolavirus infected monkeys were shipped again to Reston, and Alice, Texas in February of 1990. More Reston Ebolavirus infected monkeys were discovered in 1992 in Siena, Italy and in Texas again in March 1996. A high rate of co-infection with Simian Hemorrhagic Fever (SHF) was present in all infected monkeys. No human illness has resulted from these two outbreaks.
Ivory Coast Ebolavirus
This species of Ebola was first discovered amongst chimpanzees of the Tai Forest in C么te d鈥橧voire, Africa. On November 1, 1994, the corpses of two chimpanzees were found in the forest. Necropsies showed blood within the heart to be liquid and brown, no obvious marks seen on the organs, and one presented lungs filled with liquid blood. Studies of tissues taken from the chimps showed results similar to human cases during the 1976 Ebola outbreaks in Za茂re and Sudan. Later in 1994, more dead chimpanzees were discovered, with many testing positive to Ebola using molecular techniques. The source of contamination was believed to be the meat of infected Western Red Colobus monkeys, which the chimpanzees preyed upon.[9]
One of the scientists performing the necropsies on the infected chimpanzees contracted Ebola. She developed syndromes similar to dengue fever approximately a week after the necropsy and was transported to Switzerland for treatment. After two weeks she was discharged from hospital, and was fully recovered six weeks after the infection.
Replication
The viral attachment protein recognizes specific receptors, which may be protein, carbohydrate or lipid, on the outside of the cell. The mechanism of virus entry into host cells is unknown, but it is reasonable to assume that the glycoprotein spikes on the surface of the virion would mediate the process, as they are the only transmembrane protein present on the surface. The two types of GP, the other being sGP, are specific for different cell types.
The virus next activates and releases its own genetic material, causing the host to begin manufacturing the proteins necessary for virus reproduction using its own resources. This replication continues until the cell ruptures and bursts. The virus is then spread to neighboring cells, and continues this chain of reproduction until masses of host cells are damaged. The host then may die soon after. The spread of the virus through the population can be halted if the proper sterilization and quarantine measures are taken, as the only method by which the virus may continue to propagate is via direct contact with body fluids. In order for a successful infection the virus must first evade the immune system. One of the ways it does this is by inhibiting interferon activity. VP24 blocks IFN-伪/尾 and IFN-纬 signaling by interacting with karyopherin 伪1, the nuclear localization signal receptor for tyrosine-phosphorylated STAT1, preventing the formation of an interferon induced antiviral state. Another protein, VP35, blocks the transcription factor interferon regulatory factor 3 (IRF-3), which is important for the expression of IFN-伪/尾.
Ebola hemorrhagic fever
Symptoms
1976 photograph of two nurses standing in front of Kinshasa case #3 (Nurse Mayinga) who was treated and later died in Ngaliema Hospital, in Kinshasa, Za茂reSymptoms are varied and often appear suddenly. Initial symptoms include: high fever (at least 38.8掳C/101掳F), severe headache, muscle, joint, or abdominal pain, severe weakness and exhaustion, sore throat, nausea, and dizziness. Before an outbreak is suspected, these early symptoms are easily mistaken for malaria, typhoid fever, dysentery, influenza, or various bacterial infections, which are all far more common.
Ebola goes on to cause diarrhea, dark or bloody stool, vomiting blood, red eyes from swollen blood vessels, red spots on the skin from subcutaneous bleeding, maculopapular rash, purpura, and bleeding internally and externally from any orifice, including from the nose, mouth, rectum, genitals or needle puncture sites.
Other secondary symptoms include hypotension (less than 90mm Hg), hypovolemia, tachycardia, severe organ damage (especially the kidneys, spleen, and liver) as a result of disseminated systemic necrosis, and proteinuria. The span of time from onset of symptoms to death (usually due to hypovolemic shock and/or multiple organ failure) is usually between 7 and 14 days. By the second week of infection, patients will either defervesce (the fever will lessen) or undergo systemic multiorgan failure.
Transmission
Among humans, the virus is transmitted by direct contact with infected body fluids, or to a lesser extent, skin or mucus membrane contact. The incubation period can be anywhere from 2 to 21 days, but is generally between 5 and 10 days.
Although airborne transmission between monkeys has been demonstrated in a laboratory, there is very limited evidence for human-to-human airborne transmission in any reported epidemics. Nurse Mayinga might represent the only possible case. The means by which she contracted the virus remain uncertain.
So far all epidemics of Ebola have occurred in sub-optimal hospital conditions, where practices of basic hygiene and sanitation are often either luxuries or unknown to caretakers and where disposable needles and autoclaves are unavailable or too expensive. In modern hospitals with disposable needles and knowledge of basic hygiene and barrier nursing techniques, Ebola rarely spreads on such a large scale.
In the early stages, Ebola may not be highly contagious. Contact with someone in early stages may not even transmit the disease. As the illness progresses, bodily fluids from diarrhea, vomiting, and bleeding represent an extreme biohazard. Due to lack of proper equipment and hygienic practices, large scale epidemics occur mostly in poor, isolated areas without modern hospitals and/or well-educated medical staff. Many areas where the infectious reservoir exists have just these characteristics. In such environments all that can be done is to immediately cease all needle sharing or use without adequate sterilization procedures, to isolate patients, and to observe strict barrier nursing procedures with the use of a medical rated disposable face mask, gloves, goggles, and a gown at all times. This should be strictly enforced for all medical personnel and visitors.
Treatments
Treatment is primarily supportive and includes minimizing invasive procedures, balancing electrolytes, replacing lost coagulation factors to help stop bleeding, maintaining oxygen and blood levels, and treating any complicating infections. Despite some initial anecdotal evidence, blood serum from Ebola survivors has been shown to be ineffective in treating the virus. Interferon is also thought to be ineffective. In monkeys, administration of an inhibitor of coagulation (rNAPc2) has shown some benefit, protecting 33% of infected animals from a usually 100% (for monkeys) lethal infection. In early 2006, scientists at USAMRIID announced a 75% recovery rate after infecting four rhesus monkeys with Ebola virus and administering antisense drugs.[10]
Vaccines
Vaccines have been produced for both Ebola and Marburg that were 100% effective in protecting a group of monkeys from the disease.[11] These vaccines are based on either a recombinant Vesicular stomatitis virus or a recombinant Adenovirus[12] carrying the Ebola spikeprotein on its surface. Early human vaccine efforts, like the one at NIAID in 2003, have so far not reported any successes.[13]
Viral Reservoir
Despite numerous studies, the wildlife reservoir of Ebolavirus has not been identified. Between 1976 and 1998, from 30,000 mammals, birds, reptiles, amphibians and arthropods sampled from outbreak regions, no Ebolavirus was detected [14] apart from some genetic material found in six rodents (Mus setulosus and Praomys species) and a shrew (Sylvisorex ollula) collected from the Central African Republic in 1998.[15] Ebolavirus was detected in the carcasses of gorillas, chimpanzees and duikers during outbreaks in 2001 and 2003 (the carcasses were the source of the initial human infections) but the high mortality from infection in these species precludes them from acting as reservoirs.[14]
Plants, arthropods and birds have also been considered as reservoirs, however bats are considered the most likely candidate. Bats were known to reside in the cotton factory in which the index cases for the 1976 and 1979 outbreaks were employed and have also been implicated in Marburg infections in 1975 and 1980.[14] Of 24 plant species and 19 vertebrate species experimentally inoculated with Ebolavirus, only bats became infected.[16] The absence of clinical signs in these bats is characteristic of a reservoir species. In 2002-03, a survey of 1,030 animals from Gabon and the Republic of the Congo including 679 bats found Ebolavirus RNA in 13 fruit bats (Hyspignathus monstrosus, Epomops franquetti and Myonycteris torquata).[17] Bats are also known to be the reservoirs for a number of related viruses including Nipah virus, Hendra virus and lyssaviruses.
Ebola as a Weapon
Ebola is classified as a Category A Biological terrorism agent by the CDC as well as being considered a select agent that has the "potential to pose a severe threat to public health and safety". Ebola was considered in biological warfare research at both Fort Detrick[18] in the United States and Biopreparat[19] in the Soviet Union during the Cold War.
Ebola shows potential as a biological weapon because of its lethality but due to its relatively short incubation period it may be more difficult to spread since it may kill its victim before it has a chance to be transmitted. As a result, some developers have considered breeding it with other agents such as smallpox[20] to create so-called chimera viruses.
As a terrorist weapon, Ebola has been considered by members of Japan's Aum Shinrikyo cult, whose leader, Shoko Asahara led about 40 members to Zaire in 1992 under the guise of offering medical aid to Ebola victims in what was presumably an attempt to acquire a sample of the virus.[21]
Cultural effects
Popular description and representation
The softer side of ebola in popular cultureEbola and Marburg have served as a rich source of ideas and plotlines for many forms of entertainment. The infatuation with the virus is likely due to the high mortality rate of its victims, its mysterious nature, and its tendency to cause gruesome bleeding from body orifices.
Much of the representation of the Ebola virus in fiction and the media is considered exaggerated or myth. Many of the stories about Ebola in Preston's book The Hot Zone are refuted in the book Level 4: Virus Hunters of the CDC by Joseph B. McCormick, an employee of the CDC at the time of the early outbreaks. One pervasive myth follows that the virus kills so fast that it has little time to spread. Victims die very soon after contact with the virus. In reality, the incubation time is usually about a week. The average time from onset of early symptoms to death varies in the range 3-21 days, with a mean of 10.1. Although this would prevent the transmission of the virus to many people, it is still enough time for some people to catch the disease.
Another myth states that the symptoms of the virus are horrifying beyond belief. Victims of Ebola suffer from squirting blood, liquefying flesh, zombie-like faces and dramatic projectile bloody vomiting, at times, from even recently deceased. In actual fact, only a fraction of Ebola victims have severe bleeding that would be even somewhat dramatic to witness. Approximately 10% of patients suffer some bleeding, but this is often internal or subtle, such as bleeding from the gums. Ebola symptoms are usually limited to extreme exhaustion, vomiting, diarrhea, abdominal pain, a high fever, headaches and other body pains. I know this isn't a direct answer, but try the CDC (Center for Disease Controll).
www.CDC.gov http://www-micro.msb.le.ac.uk/3035/Filov...
http://www.freelabs.com/.../mail_handlin...
http://www.ncbi.nlm.nih.gov/ICTVdb/Image...
These three links should be enough information for you.
Hope this helps! |
