What virus causes ebola hemorrhagic fever

what virus causes ebola hemorrhagic fever

[Ebola Virus Disease (Ebola Hemorrhagic Fever)]

Ebola is a virus that causes problems with how your blood clots. It is known as a hemorrhagic fever virus. This is because the clotting problems lead to internal bleeding, as blood leaks from small blood vessels in your body. The virus also causes inflammation and tissue damage. Signs and symptoms. Onset. The length of time between exposure to the virus and the development of symptoms (incubation period) is between two and 21 days, and usually Bleeding. Recovery and death.

Ebola virus disease EVD is a deadly disease with occasional outbreaks that occur primarily on the African continent. EVD most commonly affects people and nonhuman primates hemorrhsgic as monkeys, gorillas, and chimpanzees. It is caused by an infection with a group of viruses within the genus Ebolavirus :.

Reston virus is known to cause disease in nonhuman primates and pigs, but not in people. It is unknown if Bombali virus, which was recently identified in bats, causes disease in either animals or people.

Ebola virus was first discovered in near the Ebola River in what is now the Democratic Republic of Congo. Since then, the virus has been infecting people from time to time, hmeorrhagic to outbreaks in several African countries. Scientists do not know ebolq Ebola virus comes from. However, based on the nature of similar viruses, they believe the virus is animal-borne, with bats or nonhuman primates what does a bimetallic strip do, apes, monkeys, etc.

Infected animals carrying the virus can transmit it to other animals, like apes, monkeys, duikers and humans. The virus spreads to people initially through direct contact with the blood, body fluids and tissues of animals. Ebola virus xauses spreads to other people through direct contact with body fluids of a person who is sick with or has died from EVD.

This can occur when a person touches these infected body fluids or objects that are contaminated with themand the virus gets in through broken skin or causex membranes in the eyes, nose, or mouth.

The virus can persist in certain body fluids, vrius semen, after recovery from the illness. Ebola survivors may experience side effects after their recovery, such as tiredness, what is the typical wattage of a soldering iron aches, eye and vision problems and stomach pain.

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Jul 19,  · What are Ebola virus disease symptoms and signs? a rash or red spots on the skin, eye redness, hiccups, sore throat, cough and/or coughing up blood, vomiting up blood, chest pain, mental confusion, bleeding both inside and outside the body (for . Ebola virus disease (EVD), formerly known as Ebola haemorrhagic fever, is a rare but severe, often fatal illness in humans. The virus is transmitted to people from wild animals and spreads in the human population through human-to-human transmission. The average EVD case fatality rate is around 50%. The Ebola virus is a single-stranded negative sense RNA virus belonging to the filovirus family. The Ebo- ]a virus causes Ebola virus disease (EVD). EVD is characterized by fever and malaise, muscle pain, and abnormal blood clotting. The mortality rate associated with EVD is very high, at 88%.Author: Katsunori Yanagihara, Daisuke Sasaki, Norihiko Akamatsu, Norihito Kaku, Kosuke Kosai.

Ebola , also known as Ebola virus disease EVD or Ebola hemorrhagic fever EHF , is a viral hemorrhagic fever of humans and other primates caused by ebolaviruses. The virus spreads through direct contact with body fluids , such as blood from infected humans or other animals. Control of outbreaks requires coordinated medical services and community engagement. The disease was first identified in , in two simultaneous outbreaks: one in Nzara a town in South Sudan and the other in Yambuku Democratic Republic of the Congo , a village near the Ebola River from which the disease takes its name.

The length of time between exposure to the virus and the development of symptoms incubation period is between two and 21 days, [1] [22] and usually between four and ten days. Symptoms usually begin with a sudden influenza -like stage characterised by feeling tired , fever , weakness , decreased appetite , muscular pain , joint pain , headache, and sore throat. In some cases, internal and external bleeding may occur.

Recovery may begin between seven and 14 days after first symptoms. Those who survive often have ongoing muscular and joint pain, liver inflammation , and decreased hearing, and may have continued tiredness, continued weakness, decreased appetite, and difficulty returning to pre-illness weight.

Survivors develop antibodies against Ebola that last at least 10 years, but it is unclear whether they are immune to additional infections. EVD in humans is caused by four of five viruses of the genus Ebolavirus. Ebolaviruses contain single-stranded, non-infectious RNA genomes. As with all filoviruses , ebolavirus virions are filamentous particles that may appear in the shape of a shepherd's crook, of a "U" or of a "6," and they may be coiled, toroid or branched.

Their life cycle is thought to begin with a virion attaching to specific cell-surface receptors such as C-type lectins , DC-SIGN , or integrins , which is followed by fusion of the viral envelope with cellular membranes. The most abundant protein produced is the nucleoprotein, whose concentration in the host cell determines when L switches from gene transcription to genome replication.

Replication of the viral genome results in full-length, positive-strand antigenomes that are, in turn, transcribed into genome copies of negative-strand virus progeny. Virions bud off from the cell, gaining their envelopes from the cellular membrane from which they bud.

The mature progeny particles then infect other cells to repeat the cycle. It is believed that between people, Ebola disease spreads only by direct contact with the blood or other body fluids of a person who has developed symptoms of the disease. Most people spread the virus through blood, feces and vomit.

The Ebola virus may be able to persist for more than three months in the semen after recovery, which could lead to infections via sexual intercourse. The potential for widespread infections in countries with medical systems capable of observing correct medical isolation procedures is considered low. Dead bodies remain infectious; thus, people handling human remains in practices such as traditional burial rituals or more modern processes such as embalming are at risk.

Health-care workers treating people with Ebola are at greatest risk of infection. Human-to-human transmission of EBOV through the air has not been reported to occur during EVD outbreaks, [3] and airborne transmission has only been demonstrated in very strict laboratory conditions, and then only from pigs to primates , but not from primates to primates. Airborne transmission among humans is theoretically possible due to the presence of Ebola virus particles in saliva, which can be discharged into the air with a cough or sneeze, but observational data from previous epidemics suggests the actual risk of airborne transmission is low.

Although it is not entirely clear how Ebola initially spreads from animals to humans, the spread is believed to involve direct contact with an infected wild animal or fruit bat. Animals may become infected when they eat fruit partially eaten by bats carrying the virus. Evidence indicates that both domestic dogs and pigs can also be infected with EBOV.

The natural reservoir for Ebola has yet to be confirmed; however, bats are considered to be the most likely candidate. Bats were known to roost in the cotton factory in which the first cases of the and outbreaks were observed, and they have also been implicated in Marburg virus infections in and In a — survey of 1, animals including bats from Gabon and the Republic of the Congo , immunoglobulin G IgG immune defense molecules indicative of Ebola infection were found in three bat species; at various periods of study, between 2.

Between and , in 30, mammals, birds, reptiles, amphibians and arthropods sampled from regions of EBOV outbreaks, no Ebola virus was detected apart from some genetic traces found in six rodents belonging to the species Mus setulosus and Praomys and one shrew Sylvisorex ollula collected from the Central African Republic.

However, the high rates of death in these species resulting from EBOV infection make it unlikely that these species represent a natural reservoir for the virus. Deforestation has been mentioned as a possible contributor to recent outbreaks, including the West African Ebola virus epidemic. Index cases of EVD have often been close to recently deforested lands. Like other filoviruses , EBOV replicates very efficiently in many cells , producing large amounts of virus in monocytes , macrophages , dendritic cells and other cells including liver cells , fibroblasts , and adrenal gland cells.

EBOV is thought to infect humans through contact with mucous membranes or skin breaks. Endothelial cells may be infected within three days after exposure to the virus. This damage occurs due to the synthesis of Ebola virus glycoprotein GP , which reduces the availability of specific integrins responsible for cell adhesion to the intercellular structure and causes liver damage, leading to improper clotting.

The widespread bleeding that occurs in affected people causes swelling and shock due to loss of blood volume. After infection, a secreted glycoprotein , small soluble glycoprotein sGP or GP is synthesised. EBOV replication overwhelms protein synthesis of infected cells and the host immune defences. The GP forms a trimeric complex , which tethers the virus to the endothelial cells.

The sGP forms a dimeric protein that interferes with the signalling of neutrophils , another type of white blood cell. This enables the virus to evade the immune system by inhibiting early steps of neutrophil activation. Filoviral infection also interferes with proper functioning of the innate immune system. When EVD is suspected, travel, work history, and exposure to wildlife are important factors with respect to further diagnostic efforts. Possible non-specific laboratory indicators of EVD include a low platelet count ; an initially decreased white blood cell count followed by an increased white blood cell count ; elevated levels of the liver enzymes alanine aminotransferase ALT and aspartate aminotransferase AST ; and abnormalities in blood clotting often consistent with disseminated intravascular coagulation DIC such as a prolonged prothrombin time , partial thromboplastin time , and bleeding time.

The specific diagnosis of EVD is confirmed by isolating the virus, detecting its RNA or proteins, or detecting antibodies against the virus in a person's blood. Early symptoms of EVD may be similar to those of other diseases common in Africa, including malaria and dengue fever. The complete differential diagnosis is extensive and requires consideration of many other infectious diseases such as typhoid fever , shigellosis , rickettsial diseases , cholera , sepsis , borreliosis , EHEC enteritis , leptospirosis , scrub typhus , plague , Q fever , candidiasis , histoplasmosis , trypanosomiasis , visceral leishmaniasis , measles , and viral hepatitis among others.

People who care for those infected with Ebola should wear protective clothing including masks, gloves, gowns and goggles. The infected person should be in barrier-isolation from other people. To disinfect surfaces, some lipid solvents such as some alcohol-based products, detergents, sodium hypochlorite bleach or calcium hypochlorite bleaching powder , and other suitable disinfectants may be used at appropriate concentrations.

Education of the general public about the risk factors for Ebola infection and of the protective measures individuals may take to prevent infection is recommended by the World Health Organization. Bushmeat , an important source of protein in the diet of some Africans, should be handled and prepared with appropriate protective clothing and thoroughly cooked before consumption. Since , such animal outbreaks have been monitored to predict and prevent Ebola outbreaks in humans.

If a person with Ebola disease dies, direct contact with the body should be avoided. Transportation crews are instructed to follow a certain isolation procedure, should anyone exhibit symptoms resembling EVD.

The CDC recommends monitoring for the symptoms of Ebola disease for those both at "low risk" and at higher risk. In laboratories where diagnostic testing is carried out, biosafety level 4-equivalent containment is required. Isolation refers to separating those who are sick from those who are not. Quarantine refers to separating those who may have been exposed to a disease until they either show signs of the disease or are no longer at risk. Contact tracing is considered important to contain an outbreak.

It involves finding everyone who had close contact with infected individuals and monitoring them for signs of illness for 21 days. If any of these contacts comes down with the disease, they should be isolated, tested and treated. Then the process is repeated, tracing the contacts' contacts.

While there is no approved [ by whom? Food and Drug Administration FDA advises people to be careful of advertisements making unverified or fraudulent claims of benefits supposedly gained from various anti-Ebola products.

In October , the U. Treatment is primarily supportive in nature. Blood products such as packed red blood cells , platelets , or fresh frozen plasma may also be used. Several experimental treatments are being studied.

Where hospital care is not possible, the WHO's guidelines for home care have been relatively successful. Recommendations include using towels soaked in a bleach solution when moving infected people or bodies and also applying bleach on stains.

It is also recommended that the caregivers wash hands with bleach solutions and cover their mouth and nose with a cloth. Intensive care is often used in the developed world. Death, if it occurs, follows typically six to sixteen days after symptoms appear and is often due to low blood pressure from fluid loss.

If an infected person survives, recovery may be quick and complete. Prolonged cases are often complicated by the occurrence of long-term problems, such as inflammation of the testicles , joint pains , fatigue, hearing loss, mood and sleep disturbances, muscular pain , abdominal pain, menstrual abnormalities , miscarriages , skin peeling , or hair loss.

Ebola can stay in some body parts like the eyes, [] breasts, and testicles after infection. The disease typically occurs in outbreaks in tropical regions of Sub-Saharan Africa. The first known outbreak of EVD was identified only after the fact. The Sudan outbreak infected people and killed The first identifiable case in Sudan occurred on 27 June in a storekeeper in a cotton factory in Nzara , who was hospitalised on 30 June and died on 6 July.

The first person infected with the disease was the village school's headmaster Mabalo Lokela , who began displaying symptoms on 26 August He was originally believed to have malaria and given quinine. However, his symptoms continued to worsen, and he was admitted to Yambuku Mission Hospital on 5 September.

Lokela died on 8 September 14 days after he began displaying symptoms. Soon after Lokela's death, others who had been in contact with him also died, and people in Yambuku began to panic.

The country's Minister of Health and Zaire President Mobutu Sese Seko declared the entire region, including Yambuku and the country's capital, Kinshasa , a quarantine zone. No-one was permitted to enter or leave the area, and roads, waterways, and airfields were placed under martial law. Schools, businesses and social organisations were closed. Muyembe took a blood sample from a Belgian nun; this sample would eventually be used by Peter Piot to identify the previously unknown Ebola virus.

Piot concluded that Belgian nuns had inadvertently started the epidemic by giving unnecessary vitamin injections to pregnant women without sterilizing the syringes and needles. The outbreak lasted 26 days and the quarantine lasted two weeks. Researchers speculated that the disease disappeared due to the precautions taken by locals, the quarantine of the area, and discontinuing the injections. The virus responsible for the initial outbreak, first thought to be Marburg virus , was later identified as a new type of virus related to the genus Marburgvirus.

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