Ebola has made its mark on the world over the past three decades. Since the first Ebola outbreak in 1976, numerous countries have come together in order to solve the mystery of the history of Ebola. Within a matter of days of symptoms presenting, the victims die an unimaginable death. Ebola is one of the most lethal viruses known to man with only one in every ten infected surviving (1). Key factors in understanding Ebola are its history, patterns, and the diagnosis and treatment of the disease. From 1976-79 two outbreaks of two different strains occurred simultaneously. E. Sudan was the first outbreak.
It primarily revealed itself in the region of Sudan in Africa. E. Zaire, the second strain was prominent throughout the boarders of Sudan and the Central African Republic. Ebola was named after the river Ebola that flows through Yambuku. There was a third outbreak in 1979 affecting the same region as the first. This one was less extensive, only killing thirty-four people (1). Scientists figure that Ebola is spread through direct contact with either an animal or human that is carrying the virus, usually through bodily fluids. In most cases this is accidental. Since 1995, there have been twelve outbreaks of Ebola.
Testing of human and ape victims proved there to be at least eight strains of the virus. This raised questions as to if the outbreaks have been part of one larger outbreak or if they are attached to a string of outbreaks. Ebola seems to appear and reappear in areas close to other areas that have already been victimized by Ebola (2). The human outbreaks can all be traced back to hunters or people living near the forest, scientists have been trying to find evidence of what species the virus is linked to. Bats have been researched extensively.
After many lab experiments it has been concluded that bats may be infected with the virus and overcome it without becoming fatally ill (2). There are many uncanny links from bats to the virus. In numerous outbreaks, the victim that can be traced as the first person infected, was in contact with bats shortly before becoming infected. Several people noticed bats on multiple occasions in the cotton warehouse where the first people to be infected during the 1976-79 outbreaks (1). During the Gabon outbreaks from 2001-2004, fourteen crocuses of gorillas, apes, and chimpanzees tested positive for Ebola. This lead scientist’s to believe that the dead animals were responsible for the rapid spread of the virus.
This outbreak was the first to be linked with animal mortality. During this outbreak of Ebola, over sixty gorillas and chimpanzees were found dead within the outbreak area. After further research, data proved that the mortality rate of animals in a certain population jumps just before an outbreak. This is based off of paw prints, broken vegetation, and excreta. Scientists currently agree that there is no conclusive explanation for what the host of Ebola is or where this virus originates. However, it is also agreed upon that the most likely species to be the reservoir of this lethal virus is the bat (1).
When the CDC responds to an outbreak they characterize it. The main part of characterizing the outbreak is doing community surveillance in order to confirm the total number of confirmed cases. If it is in an area that is spread out, a meeting is usually held to inform the members of the community of the signs and symptoms so that they may identify it and report it (3). Dr. Tom Ksiazek of the CDC states, “Controlling these outbreaks is really a matter of identifying active cases, [and] segregating them in health care facilities where the individuals taking care of them are protected from being infected themselves” (3).
In the majority of the countries where these outbreaks occur, their medical care is not up to the standards of the United States. Therefore, they do not wear protective gloves or gowns and as a result, are getting infected themselves. Ebola has been heavily transmitted through hospitals or health care facilities, but also through the burial of loved ones (3). In Africa, there is usually a ritual before the burial of somebody in order to cleanse him or her. It is through this ritual that there is close contact with bodily fluids; subsequently spreading the virus to one or multiple living humans (1).
Dr. Ali S. Khan stated “We cannot just look at what’s going on with people. We need to look at people, animals, and the environment, and look at where those intersect and this is where we need to work to protect the population” (3). Ebola is one of the most lethal viruses know to man. It causes great suffering amongst its victims. With an incubation period of a week, those infected with the Ebola virus quickly begin to suffer from high fever, diarrhea, vomiting, respiratory disorders and hemorrhaging, and death (1). It is essential that some sort of treatment or prevention come to pass.
The outbreaks have had mortality rates ranging from 60%-90%. With such a lethal virus, why is it that we still know so little about it? According to WHO (World Healthcare Organization) “Although Ebola incidence seems to be on the rise, it remains rare …so only a handful of labs study it. Progress is also hampered by the lack of so-called biosafety level 4 labs with space or permission to house monkeys” (4). In June of 1995 eight people infected with the Ebola virus were treated with blood transfusions containing IgO EBO antibodies.
They all had symptoms similar to those who suffered from the original epidemic. Of the eight victims infused with the antibodies, only one died. This is a significant decrease in the mortality rate. Although highly effective, there will need to be further testing on it to see how much of a role it played in the healing of the diseased. Those treated with the antibodies received better healthcare then those who remained in the center of the epidemic. Therefore, the reason for the low mortality rate remains to be unexplained until further testing is conducted (5).
Ebola viruses are negatively stranded RNA viruses. There are four subtypes; each has their own strains. The subtypes are: Zaire, Sudan, Reston, and Ivory Coast. They are named according to the geographical region that they first appeared in and likewise are the most prominent. In 1998 a study found a vaccine that prevented the virus to grow in guinea pigs. They immunized the guinea pigs with plasmids encoding vital proteins. Similar immune responses were seen in other species and allow one to conclude that it may also be applicable to humans (6). This specific immunization was not tested in humans.
In October of 2002, the National Institutes of Health’s Vaccine Research Center in Bethesda, Maryland, revealed data about a vaccine and possible treatment for Ebola. There have been many treatments proven to be effective in mice and other small rodents, however they were not successful in monkeys. The USAMRIID group treated monkeys with an anticoagulant called rNAPc2. “Given immediately after Ebola infection or within 24 hours and continuing for 8 days, the drug saved the lives of three out of nine monkeys and slowed death by several days in the remaining six.
All three controls died” (4). Due to the brutality of the virus present in these monkeys, it is “incredible” according to virologist Pierre Formenty, to see a 30% reduction in the mortality rate. There have been other strategies regarding the vaccinations of preventatives against Ebola. Nancy Sullivan from the Vaccine Research Center used a two-prong approach to injecting monkeys. This approach included “three shots of “naked DNA,” expressing Ebola’s glycoprotein, followed by one shot with an adenovirus engineered to express glycoprotein as well.
But that regimen takes 6 months to produce immunity” (4). This group of scientists was able to report that a single strand of the adenovirus is effective in twenty-eight days. This would be highly useful in a time of an outbreak (4). It would be even better if the time period for this vaccine to begin taking effect could be cut down to an even shorter time period. Heinz Feldmann, Steven Jones, and their colleagues at the National Microbiology Laboratory have created a vaccine from vesicular stomatitis virus (VSV). VSV causes symptoms consistent with foot and mouth, but not nearly as violent.
It has proven effective in guinea pigs and mice. Along with Dr. Sullivan’s vaccine, it is effective in a month’s time. However, the VSV vaccine has risks. VSV has a record of causing illness in humans. If it is proven that the VSV vaccine is not pathogenic and does not release much of the virus into the host, then the vaccine may have a successful future (4). The Prime Boost Vaccine has passed the safety trials. The next step would be a field test in Africa. This would help demonstrate efficiency and effectiveness of the vaccine.
Due to issues such as how to burry the dead has caused the relationships between the researchers and the locals to become tense. Therefore conducting a trial under these extraneous circumstances would be extremely difficult. During an outbreak in Gabon, an international team felt so threatened that they abandoned the affected town along with all of their research. WHO is trying to address these issues with African governments. Currently, very few people who become infected with Ebola go to a medical clinic or hospital.
They know that the medical personal do not have much to offer. Therefore, they opt to stay in the comfort of their own home. By staying home, they spread the virus to those surrounding them (4). This causes the virus to spread even quicker. When multiple people in the same household contract the virus they quickly become exposed to each of the infected persons bodily fluid. This not only causes the virus to further spread, but it increases the rapidity of the painful symptoms for those who are already infected, allowing them to reach the state of death quicker then normal (3).
If the vaccines were to be put into clinics, then people may be more apt to go to the clinics instead of staying home, even if it is not a 100% guarantee to be cured. This would help reduce the spread of the virus and allow researchers to better contain the virus, hopefully allowing the number of fatalities to decrease (4). Although extensive research has been and is continuously being conducted on Ebola, there are still many unknowns about this deadly virus. It has not been traced back to a specific species, even though it is believed to have come from bats. In the end, we still do not know where this virus comes from.
There are many vaccines in the testing stages, but the strenuous relationships with the people in the affected communities have caused hindrance in the final testing stages of vaccines. Ebola is a rapidly mutating virus that has left little clues to its secrets. Although science is getting close to finding a treatment for this ailment, many people will continue to suffer until the diplomatic issues are resolved and field tests are conducted successfully. REFERENCES 1. Xavier Pourret, Brice Kumulungui, Tatiana Wittmann, Ghislain Moussavou, Andre Delicat, Philippe Yaba, Dieudonne Nkoghe, Jean-Paul Moussavou, Eric Maurice Leroy.
The Natural Hisory of Ebola Virus in Africa. Microbes and Infection. 2005;7:1005-14 2. Vogel G. Forest hides the secrets of ebola: How the Deadly Disease Spreads Among Apes and Humans Remains a Mystery. Gretchen Vogel reports on a big puzzle: Financial Times. 2004 Jan 16 (11). 3. Kahn, Ali S. , Emmanuel Otaala, Eileen Farnon, and Tara Sealy. “CDC Mission Responding to Outbreaks. ” Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 12 Jan. 2012. Web. 04 Nov. 2013. 4. Enserink M. New Vaccine and Treatment Excite Ebola Researchers. Science [serial on the Internet].
(2003, Nov 14), [cited November 4, 2013]; 302(5648): 1141-1142. Available from: Computers & Applied Sciences Complete. 5. K. Mupapa, M. Massamba, K. Kibadi, K. Kuvula, A. Bwaka, M. Kipasa, R. Colebunders, J. J. Muyembe-Tamfum. Treatment of Ebola Hemorrhagic Fever with Blood Transfusions from Convalescent Patients. Oxford Journals: The Journal of Infectious Disease. 1999; 179 (supp1): S18-23 6. Ling Xu, Anthony Sanchez, Zhi-Yong Yang, Sherif R. Zaki, Elizabeth G. Nabel, Stuart T. Nichol, Gary J. Nabel. Immunization for Ebola virus Infection. Nature Medicine. !998;4:37-41.