What is Ebola hemorrhagic fever? Ebola hemorrhagic fever (Ebola HF) is a severe, often-fatal disease in humans and nonhuman primates (monkeys, gorillas, 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. There are five identified subtypes of Ebola virus.
Four of the five have caused disease in humans: Ebola-Zaire, Ebola-Sudan, Ebola-Ivory Coast and Ebola-Bundibugyo. The fifth, 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) with four of the five subtypes occurring in an animal host native to Africa.
A similar host, most likely in the Philippines, is probably associated with the Ebola-Reston subtype, which was 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. Where do cases of Ebola hemorrhagic fever occur? Confirmed cases of Ebola HF have been reported in the Democratic Republic of the Congo, Gabon, Sudan, the Ivory Coast, Uganda, and the Republic of the Congo.
No case of the disease in humans has ever been reported in the United States. Ebola-Reston virus caused severe illness and death in monkeys imported to research facilities in the United States and Italy from the Philippines; during these outbreaks, several research workers became infected with the virus, but did not become ill. Ebola HF typically appears in sporadic outbreaks, usually spread within a health-care setting (a situation known as amplification). It is likely that sporadic, isolated cases occur as well, but go unrecognized.
A table showing a chronological list of known cases and outbreaks is available below. How is Ebola virus spread? Infections with Ebola virus are acute. There is no carrier state. Because the natural reservoir of the virus is unknown, the manner in which the virus first appears in a human at the start of an outbreak has not been determined. However, researchers have hypothesized that the first patient becomes infected through contact with an infected animal. After the first case-patient in an outbreak setting is infected, the virus can be transmitted in several ways.
People can be exposed to Ebola virus from direct contact with the blood and/or secretions of an infected person. Thus, the virus is often spread through families and friends because they come in close contact with such secretions when caring for infected persons. People can also be exposed to Ebola virus through contact with objects, such as needles, that have been contaminated with infected secretions. Nosocomial transmission refers to the spread of a disease within a health-care setting, such as a clinic or hospital.
It occurs frequently during Ebola HF outbreaks. It includes both types of transmission described above. In African health-care facilities, patients are often cared for without the use of a mask, gown, or gloves. Exposure to the virus has occurred when health care workers treated individuals with Ebola HF without wearing these types of protective clothing. In addition, when needles or syringes are used, they may not be of the disposable type, or may not have been sterilized, but only rinsed before reinsertion into multi-use vials of medicine.
If needles or syringes become contaminated with virus and are then reused, numerous people can become infected. Ebola-Reston appeared in a primate research facility in Virginia, where it may have been transmitted from monkey to monkey through the air. While all Ebola virus species have displayed the ability to be spread through airborne particles (aerosols) under research conditions, this type of spread has not been documented among humans in a real-world setting, such as a hospital or household. What are the symptoms of Ebola hemorrhagic fever?
The incubation period for Ebola HF ranges from 2 to 21 days. The onset of illness is abrupt and is characterized by fever, headache, joint and muscle aches, sore throat, and weakness, followed by diarrhea, vomiting, and stomach pain. A rash, red eyes, hiccups and internal and external bleeding may be seen in some patients. 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 eyes and a skin rash, are nonspecific to the virus and are seen in other patients with diseases that occur much more frequently. However, if a person has the constellation of symptoms described above, and infection with Ebola virus is suspected, isolate the patient and notify local and state health departments and the CDC. What laboratory tests are used to diagnose Ebola hemorrhagic fever?
Antigen-capture enzyme-linked immunosorbent assay (ELISA) testing, IgM 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. 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. How is Ebola hemorrhagic fever prevented? The prevention of Ebola HF in Africa presents many challenges. Because the identity and location of the natural reservoir of Ebola virus are unknown, there are few established primary prevention measures. If cases of the disease do appear, current social and economic conditions often favor the spread of an epidemic within health-care facilities.
Therefore, health-care providers must be able to recognize a case of Ebola HF should one appear. They must also have the capability to perform diagnostic tests and be ready to employ practical viral hemorrhagic fever isolation precautions, or barrier nursing techniques. These techniques include the wearing of protective clothing, such as masks, gloves, gowns, and goggles; the use of infection-control measures, including complete equipment sterilization; and the isolation of Ebola HF patients from contact with unprotected persons.
The aim of all of these techniques is to avoid any person’s contact with the blood or secretions of any patient. If a patient with Ebola HF dies, it is equally important that direct contact with the body of the deceased patient be prevented. CDC has developed a set of tools to meet health-care facilities’ needs. In conjunction with the World Health Organization, CDC has developed practical, hospital-based guidelines, entitled Infection Control for Viral Haemorrhagic Fevers in the African Health Care Setting What challenges remain for the control and prevention of Ebola hemorrhagic fever?
. The manual describes how to recognize cases of viral hemorrhagic fever, such as Ebola HF, and prevent further nosocomial transmission by using locally available materials and few financial resources. Similarly, a practical diagnostic test that uses tiny samples from patients’ skin has been developed to retrospectively diagnose Ebola HF in suspected case-patients who have died. Scientists and researchers are faced with the challenges of developing additional diagnostic tools to assist in early diagnosis of Ebola HF and conducting ecological investigations of Ebola virus and its possible reservoir.
In addition, one of the research goals is to monitor suspected areas to determine the incidence of the disease. More extensive knowledge of the natural reservoir of Ebola virus and how the virus is spread must be acquired to prevent future outbreaks effectively.
Source:www. cdc. gov/vhf/ebola/pdf/fact-sheet. pdf The media has been buzzing about ZMapp, widely reported as an experimental top-secret, untested Ebola serum. But what is it? A look into the treatment reveals the marvels of biotechnology — and its limitations. ZMapp is not a cure or a vaccine.
It’s a cocktail of genetically engineered antibodies that boosts a patients’ ability to fight off Ebola. ZMapp actually combines two different serums made by two different companies. The first serum is called MB-003, and was developed by San Diego firm Mapp Biopharmaceutical. The second goes by the name ZMAb, and was made by Canadian company Defyrus Inc.. When Mapp Biopharmaceutical’s commercial arm LeafBio combined the two, MB-003 plus ZMAb became ZMapp. Antibodies are one of the body’s main defenses against viruses and bacteria.
When we get sick, our immune system produces antibody cells to tear apart the invaders, and restore us to health. Ebola is deadly because it disrupts the human immune system. Researchers recently discovered exactly how the virus impairs antibody production. Development of MB-003 An August 2013 Mapp Biopharmaceutical research paper explains how MB-003 was made, and shows its efficacy in treating Ebola in monkeys. The company has been working with the U. S. Army Medical Research Institute of Infectious Diseases (USAMRIID) on an Ebola treatment, in response to government fears that the virus could be used as a bioweapon.
Ebola Treatment Ethical A doctor for tropical medicine prepares a blood sample for analysis during a demonstration of Ebola-treatment capabilities at Station 59 at Charite hospital on August 11, 2014 in Berlin, Germany. The first step was for scientists to inject Ebola into mice, and extract three types of antibodies that fight different parts of the virus. It’s impossible to inject mouse antibodies into humans because the latter’s immune system will attack them as foreign invaders; so scientists spliced in human DNA to produce chimera antibodies acceptable to humans. The result was a serum they called MB-003.
The next challenge was producing enough MB-003 for an effective dose. Previous studies found that antibodies could be grown inside genetically engineered Nicotiana Benthamiana, an indigenous Australian tobacco plant, which has also been used to grow West Nile virus antibodies. Plants make good hosts because they do not carry viruses that can infect humans, and are cheaper than mammals. Researchers also discovered that plant-grown Ebola antibodies are more effective than those grown inside the ovaries of Chinese hamsters, according to Mapp Biopharmaceutical’s study. Next, Mapp Biopharmaceutical tested the MB-003 serum on monkeys.
Rhesus macaques were injected with Ebola, samples of which were provided by the USAMRIID. One or two days after infection, the monkeys received an intravenous infusion of MB-003. Forty-three percent of the infected monkeys survived. Development of ZMab Defyrus developed its serum ZMAb in a similar way. ZMAb also contains three antibodies derived from mice, and has been tested in Rhesus Macaques. In June 2012, Defyrus tested ZMAb in Rhesus Macaques, and found that 100% of infected monkeys survived when treated 24 hours after exposure. Fifty percent survived when treated 48 hours after exposure.
A November 2013 Defyrus study showed that ZMAb offered extended protection against the virus. Scientists reinfected surviving monkeys 10 weeks after their first infection, and 100% survived. What’s more, four out of the six monkeys reinfected 13 weeks after initial exposure survived. ZMapp’s origins Mapp Biopharmaceutical and Defyrus both licensed their serums to Mapp Biopharmaceutical’s commercial arm, LeafBio, which combined the two to make ZMapp. Before ZMapp could begin human trials and get approval from the U. S. Food and Drug Administration, the Ebola outbreak began in Guinea when Patient Zero died in December 2013.
Since then, the disease has claimed 1,145 lives, according to the World Health Organization. Two American doctors were infected with Ebola through their work in a Liberian hospital with the U. S. aid group Samaritan’s Purse. Kent Brantly and Nancy Writbol recovered after receiving ZMapp. However, it’s unclear whether the drug helped, or if they are getting better on their own. Around 40% of people infected with Ebola are surviving the current outbreak. The WHO said last Tuesday that use of ZMapp is “ethical,” despite the fact that it has never been previously tested on humans.
However, the serum’s supply has been exhausted, according to a Defyrus’ website. A ZMapp information sheet released by LeafBio and Mapp Biopharmaceutical explains that “very little of the drug is currently available” because it has not been evaluated for safety in humans. To gain FDA approval, a drug must undergo three stages of human trials, which means ZMapp is likely years away from FDA approval. “Mapp and its partners are cooperating with appropriate government agencies to increase production as quickly as possible,” LeafBio said in a statement on its website.
Currently, it’s unclear how long it will take to manufacture more of the serum. Source:http://mashable. com/2014/08/17/ebola-serum-zmapp/ Based on this research, we can conclude that in the status quo right now, we still haven’t found the cure for Ebola Hemorrhagic Fever. There is a serum called ZMapp developed by Mapp Biopharmaceutical but the effectiveness of this serum is still highly doubted. An article convincingly said that it miraculously cured 2 American doctors there, but still further researches can’t determine whether both of those patients were healed because of this serum or another factor instead.
As the affirmative we could use our limited amount of time and the increasing number of Ebola patients as our argument, but the opposition could rebut that by using a fact that theoretically, someone who got infected by Ebola wouldn’t die right away. That we, prefer wait a little more to give them, better, safer medications with enough amount for anyone rather than giving uncertain kinds of medicine and risking the life of some people.