Ebola hemorrhagic fever (Ebola virus disease) facts
What is Ebola hemorrhagic fever?
Ebola hemorrhagic fever is a viral disease caused by Ebola virus that results in nonspecific symptoms (see symptom section of this article) early in the disease and often causes internal and external hemorrhage (bleeding) as the disease progresses. Ebola hemorrhagic fever is considered one of the most lethal viral infections; the mortality rate (death rate) is very high during outbreaks (reports of outbreaks range from about 50%-100% of humans infected, depending on the Ebola strain); consequently the survival rate may range from about 50% to zero.
What is the history of Ebola hemorrhagic fever?
Ebola hemorrhagic fever was first noted in Zaire (currently, the Democratic Republic of the Congo or DRC) in 1976. The original outbreak was in a village near the Ebola River after which the disease was named. During that time, the virus was identified in person-to-person contact transmission. Of the 318 patients diagnosed with Ebola, 88% died. Since that time, there have been multiple outbreaks of Ebola virus, and five strains have been identified; four of the strains are responsible for the high death rates. The four Ebola strains are termed as follows: Zaire, Sudan, Tai Forest, and Bundibugyo virus, with Zaire being the most lethal strain. A fifth strain termed Reston has been found in the Philippines. The strain infects primates, pigs, and humans and causes few if any symptoms and no deaths in humans. Most outbreaks of the more lethal strains of Ebola have occurred in Africa and mainly in small- or medium-sized towns. Bats, monkeys, and other animals are thought to maintain the virus life cycle in the wild; humans can become infected from handling and/or eating infected animals. Once an Ebola outbreak is recognized, African officials isolate the area until the outbreak ceases. However, in this new outbreak that began in Africa in March 2014, some of the infected patients reached larger city centers before the outbreak was recognized; this caused further spread Ebola. The infecting Ebola virus detected this outbreak is the Zaire strain, the most pathogenic strain of Ebola. Health agencies are terming this outbreak as an "unprecedented epidemic." This epidemic spread quickly in the African countries of Guinea and Sierra Leone. In addition, countries of Liberia, Nigeria, Senegal, and Mali all reported confirmed infections with Ebola. In addition, a very few sporadic infections were noted in the United States, Spain, and the United Kingdom; most of the individuals with Ebola in these countries were either imported infections from Africa or were new infections from treating patients who originally became infected in Africa.
What causes Ebola hemorrhagic fever?
The cause of Ebola hemorrhagic fever is Ebola virus infection that results in coagulation abnormalities, including gastrointestinal bleeding, development of a rash, cytokine release, damage to the liver, and massive viremia (large number of viruses in the blood) that leads to damaged vascular cells that form blood vessels. As the massive viremia continues, coagulation factors are compromised and the microvascular endothelial cells are damaged or destroyed, resulting in diffuse bleeding internally and externally (bleeding from the mucosal surfaces like nasal passages and/or mouth and gums and even from the eyes [termed conjunctival bleeding]). This uncontrolled bleeding leads to blood and fluid loss and can cause hypotensive shock that causes death in many Ebola-infected patients.
Picture of the Ebola virus, viewed with an electron microscope; SOURCE: CDC/Frederick MurphyWhat are risk factors for Ebola hemorrhagic fever?
The risk factors for Ebola hemorrhagic fever are travel to areas where Ebola infections (see current CDC travel advisories for African countries) have been reported. In addition, association with animals (mainly primates in the area where Ebola infections have been reported) is potentially a risk factor according to the CDC. Another potential source of the virus is eating or handling "bush meat." Bush meat is the meat of wild animals, including hoofed animals, primates, bats, and rodents. Evidence for any airborne transmission of this virus is lacking. During Ebola hemorrhagic fever outbreaks, health-care workers and family members and friends associated with an infected person are at the highest risk of getting the disease. Researchers who study Ebola hemorrhagic fever viruses are also at risk of developing the disease if a laboratory accident occurs. Caring for infected patients who are near-death or disposing of bodies of individuals that have recently died of Ebola infection is a very high risk factor because in these situations, the Ebola virus is highly concentrated in any blood or bodily secretions. Caregivers are recommended to wear appropriate personal protective equipment (See the CDC site http://www.cdc.gov/vhf/ebola/healthcare-us/hospitals/infection-control.html for details).
What are Ebola virus disease symptoms and signs?
Unfortunately, early symptoms of Ebola virus disease are nonspecific and include...
As the disease progresses, patients may develop other symptoms and signs such as:
Ebola virus disease symptoms and signs may appear from about two to 21 days after exposure (average incubation period is eight to 10 days). It is unclear why some patients can survive and others die from this disease, but patients who die usually have a poor immune response to the virus. Patients who survive have symptoms that can be severe for a week or two; recovery is often slow (weeks to months) and some survivors have chronic problems such as fatigue and eye problems.
How do physicians diagnose Ebola hemorrhagic fever?
Ebola hemorrhagic fever is diagnosed preliminarily by clinical suspicion due to association with other individuals with Ebola and with the early symptoms described above. Within a few days after symptoms develop, tests such as ELISA, PCR, and virus isolation can provide definitive diagnosis. Later in the disease or if the patient recovers, IgM and IgG antibodies against the infecting Ebola strain can be detected; similarly, studies using immunohistochemistry testing, PCR, and virus isolation in deceased patients is also done usually for epidemiological purposes.
What is the treatment for Ebola hemorrhagic fever?
According to the CDC and others, standard treatment for Ebola hemorrhagic fever is still limited to supportive therapy. Supportive therapy is balancing the patient's fluid and electrolytes, maintaining their oxygen status and blood pressure, and treating such patients for any complicating infections. Any patients suspected of having Ebola hemorrhagic fever should be isolated, and caregivers should wear protective garments. Currently, there is no vaccine or specific treatment for Ebola hemorrhagic fever according to the CDC. However, the CDC recommends the following:
Patients diagnosed with Ebola in the U.S. are sent to special hospitals (Contact the CDC immediately for information for experimental vaccines, treatment protocols, and patient care and/or transfer to an appropriate facility). Experimental medical treatments of Ebola infections include immune serum, antiviral drugs, and supportive care in an intensive-care hospital facility approved by the CDC to treat Ebola infections.
What are complications of Ebola hemorrhagic fever?
Ebola hemorrhagic fever often has many complications; organ failures, severe bleeding, jaundice, delirium, shock, seizures, coma, and death (about 50%-100% of infected patients). Those patients fortunate enough to survive Ebola hemorrhagic fever still may have complications that may take many months to resolve. Survivors may experience weakness, fatigue, headaches, hair loss, hepatitis, sensory changes, and inflammation of organs (for example, the testicles and the eyes). Some may have Ebola linger in their semen for months and others may have the virus latently infect their eye(s).
Male patients may have detectable Ebola viruses in their semen for as long as six months after they survive the infection. Researchers consider the chance of getting infected with Ebola from semen is very low; however they recommend utilizing condoms for six months.
It is apparent that we don't know everything about Ebola infections. A physician who was thought to be cured of Ebola, Dr. Ian Crozier, in fall 2014 developed burning light sensitivity in his eyes. He returned to Emory University where he was treated and after several tests he was found to have Ebola infection in his eyes. However, only the fluid removed by needle from his eyes showed viable virus; his tears and the outer membrane of his eyes had no detectable virus. Consequently, doctors considered the patient not to be able to spread the virus. One of the complications was that his blue eye color turned green. Fortunately, for Dr. Crosier, treatment with steroids and antiviral agents allowed his eyes to return to normal. This unusual circumstance has suggested that follow-up eye exams are likely to be important in patients who survive Ebola infections.
What is Ebola hemorrhagic fever?
Ebola hemorrhagic fever is a viral disease caused by Ebola virus that results in nonspecific symptoms (see symptom section of this article) early in the disease and often causes internal and external hemorrhage (bleeding) as the disease progresses. Ebola hemorrhagic fever is considered one of the most lethal viral infections; the mortality rate (death rate) is very high during outbreaks (reports of outbreaks range from about 50%-100% of humans infected, depending on the Ebola strain); consequently the survival rate may range from about 50% to zero.
What is the history of Ebola hemorrhagic fever?
Ebola hemorrhagic fever was first noted in Zaire (currently, the Democratic Republic of the Congo or DRC) in 1976. The original outbreak was in a village near the Ebola River after which the disease was named. During that time, the virus was identified in person-to-person contact transmission. Of the 318 patients diagnosed with Ebola, 88% died. Since that time, there have been multiple outbreaks of Ebola virus, and five strains have been identified; four of the strains are responsible for the high death rates. The four Ebola strains are termed as follows: Zaire, Sudan, Tai Forest, and Bundibugyo virus, with Zaire being the most lethal strain. A fifth strain termed Reston has been found in the Philippines. The strain infects primates, pigs, and humans and causes few if any symptoms and no deaths in humans. Most outbreaks of the more lethal strains of Ebola have occurred in Africa and mainly in small- or medium-sized towns. Bats, monkeys, and other animals are thought to maintain the virus life cycle in the wild; humans can become infected from handling and/or eating infected animals. Once an Ebola outbreak is recognized, African officials isolate the area until the outbreak ceases. However, in this new outbreak that began in Africa in March 2014, some of the infected patients reached larger city centers before the outbreak was recognized; this caused further spread Ebola. The infecting Ebola virus detected this outbreak is the Zaire strain, the most pathogenic strain of Ebola. Health agencies are terming this outbreak as an "unprecedented epidemic." This epidemic spread quickly in the African countries of Guinea and Sierra Leone. In addition, countries of Liberia, Nigeria, Senegal, and Mali all reported confirmed infections with Ebola. In addition, a very few sporadic infections were noted in the United States, Spain, and the United Kingdom; most of the individuals with Ebola in these countries were either imported infections from Africa or were new infections from treating patients who originally became infected in Africa.
What causes Ebola hemorrhagic fever?
The cause of Ebola hemorrhagic fever is Ebola virus infection that results in coagulation abnormalities, including gastrointestinal bleeding, development of a rash, cytokine release, damage to the liver, and massive viremia (large number of viruses in the blood) that leads to damaged vascular cells that form blood vessels. As the massive viremia continues, coagulation factors are compromised and the microvascular endothelial cells are damaged or destroyed, resulting in diffuse bleeding internally and externally (bleeding from the mucosal surfaces like nasal passages and/or mouth and gums and even from the eyes [termed conjunctival bleeding]). This uncontrolled bleeding leads to blood and fluid loss and can cause hypotensive shock that causes death in many Ebola-infected patients.
Picture of the Ebola virus, viewed with an electron microscope; SOURCE: CDC/Frederick MurphyWhat are risk factors for Ebola hemorrhagic fever?
The risk factors for Ebola hemorrhagic fever are travel to areas where Ebola infections (see current CDC travel advisories for African countries) have been reported. In addition, association with animals (mainly primates in the area where Ebola infections have been reported) is potentially a risk factor according to the CDC. Another potential source of the virus is eating or handling "bush meat." Bush meat is the meat of wild animals, including hoofed animals, primates, bats, and rodents. Evidence for any airborne transmission of this virus is lacking. During Ebola hemorrhagic fever outbreaks, health-care workers and family members and friends associated with an infected person are at the highest risk of getting the disease. Researchers who study Ebola hemorrhagic fever viruses are also at risk of developing the disease if a laboratory accident occurs. Caring for infected patients who are near-death or disposing of bodies of individuals that have recently died of Ebola infection is a very high risk factor because in these situations, the Ebola virus is highly concentrated in any blood or bodily secretions. Caregivers are recommended to wear appropriate personal protective equipment (See the CDC site http://www.cdc.gov/vhf/ebola/healthcare-us/hospitals/infection-control.html for details).
What are Ebola virus disease symptoms and signs?
Unfortunately, early symptoms of Ebola virus disease are nonspecific and include...
As the disease progresses, patients may develop other symptoms and signs such as:
Ebola virus disease symptoms and signs may appear from about two to 21 days after exposure (average incubation period is eight to 10 days). It is unclear why some patients can survive and others die from this disease, but patients who die usually have a poor immune response to the virus. Patients who survive have symptoms that can be severe for a week or two; recovery is often slow (weeks to months) and some survivors have chronic problems such as fatigue and eye problems.
How do physicians diagnose Ebola hemorrhagic fever?
Ebola hemorrhagic fever is diagnosed preliminarily by clinical suspicion due to association with other individuals with Ebola and with the early symptoms described above. Within a few days after symptoms develop, tests such as ELISA, PCR, and virus isolation can provide definitive diagnosis. Later in the disease or if the patient recovers, IgM and IgG antibodies against the infecting Ebola strain can be detected; similarly, studies using immunohistochemistry testing, PCR, and virus isolation in deceased patients is also done usually for epidemiological purposes.
What is the treatment for Ebola hemorrhagic fever?
According to the CDC and others, standard treatment for Ebola hemorrhagic fever is still limited to supportive therapy. Supportive therapy is balancing the patient's fluid and electrolytes, maintaining their oxygen status and blood pressure, and treating such patients for any complicating infections. Any patients suspected of having Ebola hemorrhagic fever should be isolated, and caregivers should wear protective garments. Currently, there is no vaccine or specific treatment for Ebola hemorrhagic fever according to the CDC. However, the CDC recommends the following:
Patients diagnosed with Ebola in the U.S. are sent to special hospitals (Contact the CDC immediately for information for experimental vaccines, treatment protocols, and patient care and/or transfer to an appropriate facility). Experimental medical treatments of Ebola infections include immune serum, antiviral drugs, and supportive care in an intensive-care hospital facility approved by the CDC to treat Ebola infections.
What are complications of Ebola hemorrhagic fever?
Ebola hemorrhagic fever often has many complications; organ failures, severe bleeding, jaundice, delirium, shock, seizures, coma, and death (about 50%-100% of infected patients). Those patients fortunate enough to survive Ebola hemorrhagic fever still may have complications that may take many months to resolve. Survivors may experience weakness, fatigue, headaches, hair loss, hepatitis, sensory changes, and inflammation of organs (for example, the testicles and the eyes). Some may have Ebola linger in their semen for months and others may have the virus latently infect their eye(s).
Male patients may have detectable Ebola viruses in their semen for as long as six months after they survive the infection. Researchers consider the chance of getting infected with Ebola from semen is very low; however they recommend utilizing condoms for six months.
It is apparent that we don't know everything about Ebola infections. A physician who was thought to be cured of Ebola, Dr. Ian Crozier, in fall 2014 developed burning light sensitivity in his eyes. He returned to Emory University where he was treated and after several tests he was found to have Ebola infection in his eyes. However, only the fluid removed by needle from his eyes showed viable virus; his tears and the outer membrane of his eyes had no detectable virus. Consequently, doctors considered the patient not to be able to spread the virus. One of the complications was that his blue eye color turned green. Fortunately, for Dr. Crosier, treatment with steroids and antiviral agents allowed his eyes to return to normal. This unusual circumstance has suggested that follow-up eye exams are likely to be important in patients who survive Ebola infections.
Source: http://www.rxlist.com
Source: http://www.rxlist.com
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