Friday, April 4, 2014

Ebola Virus Disease- Ebola Virus – Symptoms, Pictures, Structure, facts and History »

Fact sheet N°103
Updated March 2014

Key facts

  • The Ebola virus causes Ebola virus disease (EVD; formerly known as Ebola haemorrhagic fever) in humans.
  • EVD outbreaks have a case fatality rate of up to 90%.
  • EVD outbreaks occur primarily in remote villages in Central and West Africa, near tropical rainforests.
  • The virus is transmitted to people from wild animals and spreads in the human population through human-to-human transmission.
  • Fruit bats of the Pteropodidae family are considered to be the natural host of the Ebola virus.
  • No specific treatment or vaccine is available for use in people or animals.

The Ebola virus causes Ebola virus disease (EVD) in humans, with a case fatality rate of up to 90%.
Ebola first appeared in 1976 in 2 simultaneous outbreaks, in Nzara, Sudan, and in Yambuku, Democratic Republic of Congo. The latter was in a village situated near the Ebola River, from which the disease takes its name.
Genus Ebolavirus is 1 of 3 members of the Filoviridae family (filovirus), along with genus Marburgvirus and genus Cuevavirus. Genus Ebolavirus comprises 5 distinct species:
  • Bundibugyo ebolavirus (BDBV)
  • Zaire ebolavirus (EBOV)
  • Reston ebolavirus (RESTV)
  • Sudan ebolavirus (SUDV)
  • Taï Forest ebolavirus (TAFV).
BDBV, EBOV, and SUDV have been associated with large EVD outbreaks in Africa, whereas RESTV and TAFV have not. The RESTV species, found in Philippines and the People’s Republic of China, can infect humans, but no illness or death in humans from this species has been reported to date.


Ebola is introduced into the human population through close contact with the blood, secretions, organs or other bodily fluids of infected animals. In Africa, infection has been documented through the handling of infected chimpanzees, gorillas, fruit bats, monkeys, forest antelope and porcupines found ill or dead or in the rainforest.
Ebola then spreads in the community through human-to-human transmission, with infection resulting from direct contact (through broken skin or mucous membranes) with the blood, secretions, organs or other bodily fluids of infected people, and indirect contact with environments contaminated with such fluids. Burial ceremonies in which mourners have direct contact with the body of the deceased person can also play a role in the transmission of Ebola. Men who have recovered from the disease can still transmit the virus through their semen for up to 7 weeks after recovery from illness.
Health-care workers have frequently been infected while treating patients with suspected or confirmed EVD. This has occurred through close contact with patients when infection control precautions are not strictly practiced.
Among workers in contact with monkeys or pigs infected with Reston ebolavirus, several infections have been documented in people who were clinically asymptomatic. Thus, RESTV appears less capable of causing disease in humans than other Ebola species.
However, the only available evidence available comes from healthy adult males. It would be premature to extrapolate the health effects of the virus to all population groups, such as immuno-compromised persons, persons with underlying medical conditions, pregnant women and children. More studies of RESTV are needed before definitive conclusions can be drawn about the pathogenicity and virulence of this virus in humans.

Signs and symptoms

EVD is a severe acute viral illness often characterized by the sudden onset of fever, intense weakness, muscle pain, headache and sore throat. This is followed by vomiting, diarrhoea, rash, impaired kidney and liver function, and in some cases, both internal and external bleeding. Laboratory findings include low white blood cell and platelet counts and elevated liver enzymes.
People are infectious as long as their blood and secretions contain the virus. Ebola virus was isolated from semen 61 days after onset of illness in a man who was infected in a laboratory.
The incubation period, that is, the time interval from infection with the virus to onset of symptoms, is 2 to 21 days.


Other diseases that should be ruled out before a diagnosis of EVD can be made include: malaria, typhoid fever, shigellosis, cholera, leptospirosis, plague, rickettsiosis, relapsing fever, meningitis, hepatitis and other viral haemorrhagic fevers.
Ebola virus infections can be diagnosed definitively in a laboratory through several types of tests:
  • enzyme-linked immunosorbent assay (ELISA)
  • antigen detection tests
  • serum neutralization test
  • reverse transcriptase polymerase chain reaction (RT-PCR) assay
  • virus isolation by cell culture.
Samples from patients are an extreme biohazard risk; testing should be conducted under maximum biological containment conditions.

Prevention and treatment

No vaccine for EVD is available. Several vaccines are being tested, but none are available for clinical use.
Severely ill patients require intensive supportive care. Patients are frequently dehydrated and require oral rehydration with solutions containing electrolytes or intravenous fluids.
No specific treatment is available. New drug therapies are being evaluated.

Natural host of Ebola virus

In Africa, fruit bats, particularly species of the genera Hypsignathus monstrosus, Epomops franqueti and Myonycteris torquata, are considered possible natural hosts for Ebola virus. As a result, the geographic distribution of Ebolaviruses may overlap with the range of the fruit bats.

Ebola virus in animals

Although non-human primates have been a source of infection for humans, they are not thought to be the reservoir but rather an accidental host like human beings. Since 1994, Ebola outbreaks from the EBOV and TAFV species have been observed in chimpanzees and gorillas.
RESTV has caused severe EVD outbreaks in macaque monkeys (Macaca fascicularis) farmed in Philippines and detected in monkeys imported into the USA in 1989, 1990 and 1996, and in monkeys imported to Italy from Philippines in 1992.
Since 2008, RESTV viruses have been detected during several outbreaks of a deadly disease in pigs in Philippines and China. Asymptomatic infection in pigs has been reported and experimental inoculations have shown that RESTV cannot cause disease in pigs.


Controlling Ebola Reston in domestic animals
No animal vaccine against RESTV is available. Routine cleaning and disinfection of pig or monkey farms (with sodium hypochlorite or other detergents) should be effective in inactivating the virus.
If an outbreak is suspected, the premises should be quarantined immediately. Culling of infected animals, with close supervision of burial or incineration of carcasses, may be necessary to reduce the risk of animal-to-human transmission. Restricting or banning the movement of animals from infected farms to other areas can reduce the spread of the disease.
As RESTV outbreaks in pigs and monkeys have preceded human infections, the establishment of an active animal health surveillance system to detect new cases is essential in providing early warning for veterinary and human public health authorities.
Reducing the risk of Ebola infection in people
In the absence of effective treatment and a human vaccine, raising awareness of the risk factors for Ebola infection and the protective measures individuals can take is the only way to reduce human infection and death.
In Africa, during EVD outbreaks, educational public health messages for risk reduction should focus on several factors:
  • Reducing the risk of wildlife-to-human transmission from contact with infected fruit bats or monkeys/apes and the consumption of their raw meat. Animals should be handled with gloves and other appropriate protective clothing. Animal products (blood and meat) should be thoroughly cooked before consumption.
  • Reducing the risk of human-to-human transmission in the community arising from direct or close contact with infected patients, particularly with their bodily fluids. Close physical contact with Ebola patients should be avoided. Gloves and appropriate personal protective equipment should be worn when taking care of ill patients at home. Regular hand washing is required after visiting patients in hospital, as well as after taking care of patients at home.
  • Communities affected by Ebola should inform the population about the nature of the disease and about outbreak containment measures, including burial of the dead. People who have died from Ebola should be promptly and safely buried.
Pig farms in Africa can play a role in the amplification of infection because of the presence of fruit bats on these farms. Appropriate biosecurity measures should be in place to limit transmission. For RESTV, educational public health messages should focus on reducing the risk of pig-to-human transmission as a result of unsafe animal husbandry and slaughtering practices, and unsafe consumption of fresh blood, raw milk or animal tissue. Gloves and other appropriate protective clothing should be worn when handling sick animals or their tissues and when slaughtering animals. In regions where RESTV has been reported in pigs, all animal products (blood, meat and milk) should be thoroughly cooked before eating.
Controlling infection in health-care settings
Human-to-human transmission of the Ebola virus is primarily associated with direct or indirect contact with blood and body fluids. Transmission to health-care workers has been reported when appropriate infection control measures have not been observed.
It is not always possible to identify patients with EBV early because initial symptoms may be non-specific. For this reason, it is important that health-care workers apply standard precautions consistently with all patients – regardless of their diagnosis – in all work practices at all times. These include basic hand hygiene, respiratory hygiene, the use of personal protective equipment (according to the risk of splashes or other contact with infected materials), safe injection practices and safe burial practices.
Health-care workers caring for patients with suspected or confirmed Ebola virus should apply, in addition to standard precautions, other infection control measures to avoid any exposure to the patient’s blood and body fluids and direct unprotected contact with the possibly contaminated environment. When in close contact (within 1 metre) of patients with EBV, health-care workers should wear face protection (a face shield or a medical mask and goggles), a clean, non-sterile long-sleeved gown, and gloves (sterile gloves for some procedures).
Laboratory workers are also at risk. Samples taken from suspected human and animal Ebola cases for diagnosis should be handled by trained staff and processed in suitably equipped laboratories.

WHO response

WHO provides expertise and documentation to support disease investigation and control.
Recommendations for infection control while providing care to patients with suspected or confirmed Ebola haemorrhagic fever are provided in: Interim infection control recommendations for care of patients with suspected or confirmed Filovirus (Ebola, Marburg) haemorrhagic fever, March 2008. This document is currently being updated.
WHO has created an aide–memoire on standard precautions in health care (currently being updated). Standard precautions are meant to reduce the risk of transmission of bloodborne and other pathogens. If universally applied, the precautions would help prevent most transmission through exposure to blood and body fluids.
Standard precautions are recommended in the care and treatment of all patients regardless of their perceived or confirmed infectious status. They include the basic level of infection control—hand hygiene, use of personal protective equipment to avoid direct contact with blood and body fluids, prevention of needle stick and injuries from other sharp instruments, and a set of environmental controls.

Table: Chronology of previous Ebola virus disease outbreaks

YearCountryEbolavirus speciesCasesDeathsCase fatality
2012Democratic Republic of CongoBundibugyo572951%
2008Democratic Republic of CongoZaire321444%
2007Democratic Republic of CongoZaire26418771%
2003 (Nov-Dec)CongoZaire352983%
2003 (Jan-Apr)CongoZaire14312890%
1996South Africa (ex-Gabon)Zaire11100%
1996 (Jul-Dec)GabonZaire604575%
1996 (Jan-Apr)GabonZaire312168%
1995Democratic Republic of CongoZaire31525481%
1994Cote d'IvoireTaï Forest100%
1977Democratic Republic of CongoZaire11100%
1976Democratic Republic of CongoZaire31828088%

For more information contact:

WHO Media centre
Telephone: +41 22 791 2222
credit to : World Health Organization

How is Ebola hemorrhagic fever treated?

There is no standard treatment for Ebola HF. Patients receive supportive therapy. This consists of balancing the patient's fluids and electrolytes, maintaining their oxygen status and blood pressure, and treating them for any complicating infections.

There is no standard treatment for Ebola HF. Patients receive supportive therapy. This consists of balancing the patient's fluids and electrolytes, maintaining their oxygen status and blood pressure, and treating them for any complicating infections.

What is Ebola Virus?

Pictures of Ebola Virus
Picture 1 – Ebola Virus
Source – blogspot
The Filoviridae family has two specific genera: Ebola and Marburg viruses.   Although there is no such exact scientific name for ebola virus, yet it gets its name from the Ebola River Valley in Zaire (presently being renamed as Democratic Republic of Congo). For those enquiring as to who discovered ebola virus, the answer lies in the fact that it was discovered by Dr. Ngoy Mushola.  It is responsible for causing ebola hemorrhagic fever disease (EHF) in humans and primates which causes the destruction of blood vessels and problems related to the coagulation of blood.

Types or Classification of Ebola Virus

Within the ebolavirus genus, there are five different recognized species which can be distinguished on the basis of their genetic sequences and the immune reaction they evoke in different individuals. They can be categorized as under:-

Zaire Ebola Virus (ZEBOV)

Ebola virus outbreaks took place for the first time in Yambuku, Zaire in the year 1976. The virus causing such outbreaks has been named as the Zaire ebola virus. It is the most dangerous species of ebola virus that has claimed that has had the largest number of ebola virus victims which has led to the highest number of ebola virus deaths. Its symptoms include a chilly feeling accompanied with high fever which shares its similarity with the symptoms of malaria. The basic cause believed to lie behind the spread of the disease is the reuse of the same needle initially used for Lokela’s injection without sterilization. Ebola virus transmission may also be attributed to the unhygienic and poor traditional burial method that was followed by the South African tribes. This has resulted in the occurrence of the disease more than once in Congo, Gabon and other places in South Africa.

Ebola Sudan Virus (SEBOV)

This is a second kind of species of ebola virus that is believed to have originated in Nzara, Sudan in 1976. The first case of Sudan ebola virus origin can be traced to the cotton factory workers of Sudan who were exposed to the same. The outbreak of Sudan ebola virus has been simultaneous with the outbreak of Zaire ebola virus. The disease also broke out in 1979, 2000 and 2004, most recently. The agent of transmission for Sudan ebola virus is still unknown but it has an average fatality rate.

Ebola Reston Virus (REBOV)

For those who want to know as to what is Ebola Reston virus must be enlightened with the ebola virus fact that it was discovered in 1989 in Reston, Virginia. Although it is non-pathogenic to humans, yet it has been found to affect primates such as monkeys. Subsequently Ebola Reston virus outbreaks have occurred in Texas and Italy. Interestingly Ebola Reston virus in pigs has been detected very recently with its outbreak in Philippines.

Ivory Coast Ebola Virus (CIEBOV)

Also known as Tai ebola virus, the origin of Ivory Coast ebola virus can be traced to the Tai forests of the Côte d’Ivoire in Africa, where the outbreak of this virus took place for the first time in 1994. The initial outbreak was among the wild African chimpanzees from whom it is believed to have got transmitted to humans during the process of conduction of necropsy on the dead body of the infected chimpanzees who had contracted the same.

Bundibugyo Ebola Virus

An outbreak of ebola virus disease in the Bundibugyo district of Uganda in 2007 and 2008 led to the detection of a species of ebola virus that was hitherto unknown. The ebola virus was named after its place of outbreak for the first time and there were at least 100 or more ebola virus victims.

Signs and Symptoms of Ebola Virus

Ebola Virus Photos
Image 2 – Ebola Virus Picture
Source – cbsnews
The period of incubation for ebola virus hemorrhagic fever is usually 5 to 18 days but may extend from 2 to 21 days depending on the type of virus that one contracts. The Ebola virus symptoms hemorrhagic disease that is generally noticed in individuals contracting the viral disease are high fever, nausea and vomiting, headache, muscular pain, malaise, inflammation of the pharynx, and diarrhea accompanied with bloody discharge, and the development of maculopapular rashes along with bleeding at other body orifices. Besides these, abdominal pain, joint pain, chest pain, coagulopathy, hiccups, low blood pressure, sclerotic arterioles, purpura, petechia are the other symptoms that are particular to the species of Zaire ebola virus and Sudan ebola virus. This kind of reference to these two particular species of virus is due to the fact that the other three species of ebola virus are either non – pathogenic to human beings or have very few cases to facilitate the detection of its symptoms.

Virology of Ebola Virus

Ebola Virus Structure

Diagram of Ebola Virus
Picture 3 – Ebola Virus Diagram
The structure of Ebola virus is actually thread-like in nature as is common for all viruses belonging to the family of filoviridae. The ebola virus facts suggest that the size of ebola virus VP30 is actually 288 amino acids in length. The ebola virus virions may vary in terms of their shape and size. They may be in the form of a coil, circle, and branch or may also appear in the form of a U or a 6. By size they are generally 80 nm in diameter but may extend from 800 to 1000 nm in several cases. The virions are surrounded by a bilayer of lipid molecules that anchor and protect the glycoprotein projecting long spikes from its surface which are usually 7 to 10 nm long. This outer layer of the virion is called the envelope. Within the virions are bound the neucleocapsids, which are usually 80 nm in size and contain genomic Ribonucleic acid along with viral proteins such as  VP35, VP30, NP and L. The nucleocapsid contains a central channel of 20-30 nm in diameter. The viral proteins VP24 and VP40 are located in the space between the glycoprotein envelope (GP) and the nucleocapsid of the virion, called the Matrix. The true structure of ebola virus can be obtained with the help of electron micrographs.

Ebola Virus Genome or Hereditary Information

The ebola virus information about its hereditary or biological composition has been discerned with the help of modern scientific research with the help of advanced scientific tools and equipments. A single virion of ebola virus contains a molecule of negative sense RNA, which is single stranded and linear in shape. The length of the molecule may extend from 18,959 to 18,961 in length. Within it, the 3’ terminus is the leader which is actually not polyadenaylated. Then follows the non structural proteins or the NPs such as VP35 and the VP40 and the glycoproteins, namely VP30, and VP24. The order ends with the terminus 5’ which is actually capped. The exactly 472 and 732 nucleotides that have been found from the end of 3’ and 5’ terminus are capable of carrying signals that are vital in controlling transcription such as that of the viral genome from the RNA dependent polymerase to the mRNAs. . These nucleotides are also vital for ebola virus replication and facilitate the process of packaging of the viral genomes into newly formed virions. The genomes are non infectious and so do not cause ebola virus infections. The NP and L genes have been identified as endogenous in the genomes of some mammals.

Ebola Virus Replication

Replication of Ebola Virus
Photo 4 - Ebola Virus Replication
Source – stanford
The ebola viruses are actually acellular in nature and as such do not have the possibility of growing up themselves. They compensate this incapability of themselves by using the cell of the host for the purpose of multiple production and reproduction. The initiation of the mechanism is done by the ebola virus by attaching itself to the receptors of the cell of the host. This is done through the glycoprotein called the surface peplomer by engulfing the protein molecules and forming a vesicle around the host cell. This process is known as Endocytosis. After this, the ebola virus releases the nucleocapsid into the cytoplasm of the host cell and it also begins surrounding the capsid of the host cell.
In this process, the negative ssRNA helps in the synthesis (3’-5’) of monocistronic, polyadenylated mRNAs. This also translates the mRNA into viral proteins. Next the viral proteins are processed and the glycoprotein precursor is cleaved into the glycoprotein molecules of the types 1 and 2. These glycoproteins have already undergone the enzymatic process of attaching glycans to proteins which is known as the process of Glycosylation. The two different glycoprotein molecules assemble together to form Heterodimers, which are actually made up of two similar but not exactly identical molecules. Then the molecules multiply to form a trimer and proceed to form surface peplomer which are located on the surface of the shell of the lipoprotein. The cell releases the secreted glycoprotein and the delta peptide.
With the rise in the levels of the vital protein, the process shifts from ebola virus transcription and translation to its replication. The +ssRNA is synthesized using the pattern of the negative-sense RNA and this further helps in the synthesis of a new genomic (-) ssRNA which is itself surrounded by a capsid. This leads to the formation of the neuclocapsides and the ebola virus envelope proteins with the plasma membrane of the cell of the host. Then the virus reproduces itself by the process of asexual reproduction called budding and this leads to the total destruction of the host cell.

Ebola Virus Epidemiology

Ebola Virus Natural Reservoirs

Although there have been a number of cases of ebola virus outbreaks both in the past and the present, yet it has been difficult for scientists to ascertain the exact reservoir species of the virus. This is the reason a mystery prevails on the life cycle of ebola virus as it is difficult to understand the distinct ebola virus effects that occurs among the hosts, who may be primates or humans. The first detected cases of ebola virus outbreaks have been in Africa among the dead bodies and carcasses of chimpanzees, gorillas, rodents, duikers and shrews. The virus very soon got transmitted from the animals causing ebola virus infections in humans. The significant number of ebola virus deaths caused by the viral infection in these species does not allow one to consider them a natural reservoir for the same.
However, birds, arthropods and the plants are considered to be the possible reservoirs of ebola virus disease. The most likely reservoir of ebola virus is considered to be that of the bats. This is due to the fact that there are hardly any clinical signs that can be found in them. The most recent studies indicate bats were to be blamed for the ebola virus outbreaks of 1976 and 1979. In a similar fashion, they are also considered to be the cause behind the Marburg infections of the 1970s and 80s. A recent experiment conducted upon 24 plant species and 19 vertebrates who were inoculated with ebola virus have resulted in showing the bats as the infected ones, carrying and spreading the disease. Specifically, the fruit bat species such as Epomops franqueti, Hypsignathus monstrosus, and Myonycteris torquata have been recently found to carry the virus without showing any symptoms of the same.

Ebola Virus Transmission

The transmission of Ebola virus between natural reservoir species and humans is quite rare. The outbreaks can usually be traced to a single index case where humans may contract the disease while handling the dead carcasses of marsupials and some other animals. The usual mechanism of transmission that has been detected by researchers considers bats to be the primary cause of ebola virus transmission to first terrestrial animals which may further be carried to humans. Ebola virus is usually transmitted either directly or indirectly depending on the agent and nature of transmission. Direct transmission takes place between humans who come in contact with those who have been originally affected. The ‘hot virus’ as it also named may also get transmitted through fluids in the body such as the blood or other forms of secretions. This happens mostly in hospitals and mortuaries but may also spread within the family itself even if a single member is infected. Hospitals belonging to rural areas which are unhygienic in nature and lack medical tools and implements and adequate sanitation facilities are the ones which make patients highly susceptible to the disease.
Conjunctiva and oral exposure are considered to cause ebola virus disease in primates other than humans. Besides these, ebola viruses are highly infectious in nature and were the sole reason behind the contraction of the disease by a scientist while conducting an experiment in the laboratory. Due to the potential characteristic of the virus spreading through the air, ebola virus has also been classified as a highly potential agent of bioterrorism.

Ebola Virus History

history of ebola virus
Picture 5
 – Ebola Virus Geographic Distribution
Source – wikimedia
The first case of ebola virus outbreak occurred in the form of ebola virus hemorrhagic fever in the year, 1976 in Zaire. The disease also broke out in Sudan in the same year. The species that led to the outbreak in Zaire has the highest fatality rates than any other known human pathogenic virus. Since then history of Ebola virus has noticed several successive outbreaks in Africa in the recent years of the 1990s and the millennium 2000. The lack of knowledge of the nature of lethality of the virus and its emergence as an epidemic in parts of the African subcontinent led to the medical scientists to hold a proceeding of an International Colloquium on Ebola Virus Infection & other Hemorrhagic Fevers in the month of December, in the year 1977. It was held in Antwerp in Belgium.
Similarly the investigation of the Simian hemorrhagic fever virus (SHFV) that broke out in 1989 led to the discovery of a new species of viruses that appeared quite similar to ebola that was detected in Crab-eating Macaques of Philippines. The lethality of the disease drew attention of scientists from across continents. Along these lines, several ebola virus books and journals have also been made available worldwide.
The lethality of the ebola virus can be gauged from the fact that it even has the potential to penetrate an AIDS patient and cause immense destruction to the host cell. Given the destructive nature of the virus and its complex nature, it is quite unfortunate that there is no ebola virus vaccine or treatment that is available to actually prevent the destruction that it causes to both humans and animals. Ebola virus prevention rests on the fact that one should take precautions as to avoid any physical contact with the bodily remains of an animal which may have contracted the same. Direct physical contact should also be avoided with any person who is infected in order to prevent oneself from getting infected from such a lethal viral disease.

Pictures of Ebola Virus

To get a real view of the lethality of Ebola virus let us have a glimpse of the same.
Mechanisms for Enhancement of Ebola
Picture 6 – Mechanisms for Enhancement of Ebola Virus Infection
Source – hokudai
Ebola Virus photos
Ebola Virus Images
Picture 7 – Ebola Virus Particles
Source – ens-lyon
References :
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What is Ebola hemorrhagic fever?

Ebola hemorrhagic fever (Ebola HF) is a severe, often-fatal disease in humans and nonhuman primates (monkeys and chimpanzees) that has appeared sporadically since its initial recognition in 1976.

The disease is caused by infection with Ebola virus, named after a river in the Democratic Republic of the Congo (formerly Zaire) in Africa, where it was first recognized. The virus is one of two members of a family of RNA viruses called the Filoviridae. Three of the four species of Ebola virus identified so far have caused disease in humans: Ebola-Zaire, Ebola-Sudan, and Ebola-Ivory Coast. The fourth, Ebola-Reston, has caused disease in nonhuman primates, but not in humans.    

Where is Ebola virus found in nature?

The exact origin, locations, and natural habitat (known as the "natural reservoir") of Ebola virus remain unknown. However, on the basis of available evidence and the nature of similar viruses, researchers believe that the virus is zoonotic (animal-borne) and is normally maintained in an animal host that is native to the African continent. A similar host is probably associated with Ebola-Reston isolated from infected cynomolgous monkeys that were imported to the United States and Italy from the Philippines. The virus is not known to be native to other continents, such as North America.

What are the symptoms of Ebola hemorrhagic fever?

The signs and symptoms of Ebola HF are not the same for all patients. The table below outlines symptoms of the disease, according to the frequency with which they have been reported in known cases.

Time Frame
Symptoms that occur in most Ebola patients
Symptoms that occur in some Ebola patients
Within a few days of becoming infected with the virus:
high fever, headache, muscle aches, stomach pain, fatigue, diarrhea
sore throat, hiccups, rash, red and itchy eyes, vomiting blood, bloody diarrhea
Within one week of becoming infected with the virus:
chest pain, shock, and death
blindness, bleeding

Researchers do not understand why some people are able to recover from Ebola HF and others are not. However, it is known that patients who die usually have not developed a significant immune response to the virus at the time of death.

How is Ebola hemorrhagic fever clinically diagnosed?

Diagnosing Ebola HF in an individual who has been infected only a few days is difficult because early symptoms, such as red and itchy eyes and a skin rash, are nonspecific to the virus and are seen in other patients with diseases that occur much more frequently. If a person has the constellation of symptoms described in the table above, and infection with Ebola virus is suspected, several laboratory tests should be done promptly. These include a blood film examination for malaria and a blood culture. If the suspected patient has bloody diarrhea, a stool culture should also be performed.

Ebola Hemorrhagic Fever: Fact Sheet

What laboratory tests are used to diagnose Ebola hemorrhagic fever?

Antigen-capture enzyme-linked immunosorbent assay (ELISA) testing, IgG ELISA, polymerase chain reaction (PCR), and virus isolation can be used to diagnose a case of Ebola HF within a few days of the onset of symptoms. Persons tested later in the course of the disease or after recovery can be tested for IgM and IgG antibodies; the disease can also be diagnosed retrospectively in deceased patients by using immunohistochemistry testing, virus isolation, or PCR.