What is ebola ?
Ebola or Ebola hemorrhagic fever is a common viral illness in humans caused by the Ebola virus. The disease is rare and occurs in the form of regional outbreaks in countries in central Africa. The name comes from the river Ebola in Congo (then Zaire) where there was a second outbreak in 1976 and Ebola first by Peter Piot was recognized and demonstrated in place Yambuku, located 95 kilometers from the river Ebola. The condition causes a high mortality rate and there is no specific treatment or cure available against the virus.
Ebola symptoms and disease progression
The incubation period of Ebola is 2 to 21 days. Usually, the patient develops after 7 days of the first symptoms. After the first symptoms: fever, severe headache and strong pains occur, the disease may worsen quickly. An atypical, but serious symptom is hiccups, which affects 15% of the patients.
In the beginning of the disease, the patient will exhibit non-specific flu-like symptoms, such as sore throat, fever, and general malaise. These symptoms come on quickly and worsen rapidly. Headache, muscle and joint pain, fever with chills, loss of appetite and a feeling of weakness are the most common early symptoms.
Patches forming a rash sometimes shows up around day five of the infection, mainly on the trunk. This result is not very distinctive since it occurs only in about 15% of the cases. Followed by gastrointestinal symptoms such as abdominal pain, vomiting and diarrhea. Deterioration and bleeding from the mucous membranes: conjunctivitis, difficult and painful swallowing and bleeding in several places of the gastrointestinal tract. Bleeding of the mucous membranes come in the half of the cases. In subsequent phases may prevent further bleeding, inflammation of the heart muscle, and pulmonary edema.
In the second week of illness are seen in line early recovery or a further deterioration of diffuse blood clotting in the vessels, general organ failure and shock. If the patient dies from the infection, this is usually done in the second week. Recovery takes a long time. During this period, one sees regularly teelbalontsteking complications such as liver inflammation, joint pain, inflammation of spinal or bone marrow and conjunctivitis.
Ebola infections
The virus is transferable via all the body fluids. The version that appears in the Congo, is probably through direct contact with the patient are spread by nursing, or contact with the dead body. Not everyone who is infected with the virus dies this; the mortality rate is estimated to be around 50%. In all probability, play individual factors such as the health and genetic predisposition a role in the susceptibility to the virus. Ebola was first scientifically recorded in 1976. Since that outbreak and the outbreak in 2014, there have been about twenty several smaller outbreaks. Until the outbreak of the disease in 2014 in the West African countries of Guinea and Liberia died outbreak by several hundred people. Nevertheless, the Ebola virus was months topic of conversation when in 1995 there occurred an outbreak in Congo again. In early 2005 an outbreak of Ebola occurred in Etoumbi.
Bats are the most likely source for filoviruses. The viruses are found in several species of bats that live in Africa. They spread the virus through their feces. Different animals in the African tropical rainforest can be infected with the virus, such as chimpanzees, gorillas and antelope. If people such slaughter and eat, they can also get the virus. Meliandou around, the village of the first patient in Guinea, bats are eaten.
Epidemics
1976
The first documented epidemics occurred in 1976 in Sudan and Zaire.
Sudan
In the period June to November 1976 an Ebola epidemic broke out in the cities Nzara, Maridi, Tembura and Juba in southern Sudan out. The outbreak started in a cotton mill in Nzara where the first patient became ill on June 27, 1976, who died on 6 July. Colleagues of these patients were also ill, and the disease spread to family members and health professionals. The epidemic spread in August strongly at a hospital in Maridi. The care of the sick probably both played a role. Because many staff were ill broke panic among the patients and the staff present, so that the hospital was largely abandoned. The last infection was registered on November 25, 1976.
During this outbreak were recorded 284 casualties, including 151 deceased. The cause of the infection was attributed to contact between humans and pests in the cotton plant as the black rat, bat: the Tadarida trevori and mosquitoes.
Initially thought this epidemic was the likely source of the outbreak of the disease in Zaire in the same year. Argument was the high mobility of people between Nzara and the Bumba region in Zaire. Years later, however, proved to be two distinct species of the Ebola virus, which the Sudan Ebola virus was responsible for this epidemic.
Zaire
In the north of the former Zaire, the Congo-Kinshasa, broke into the period September 1 to October 24, 1976 an epidemic of Ebola out. Among these, 318 infections, including 280 deaths recorded.
The epidemic began in Bumba in Equateur region, near the town Yambuku 95 km south of the Ebola River. The first patient, a 44 year old teacher at a missionary school, September 1 became ill after being given an injection of chloroquine against malaria on August 26 in a hospital in the Belgian mission in Yambuku. Others became ill after these injections or after direct contact with other infected patients. It was therefore assumed that a lack of hygiene played a role in spreading the disease. Here, the first patient had infected the needle, which is then also others were injected in the context of vaccination. Late September is also a Belgian sister ill. She was transferred to the hospital in Kinshasa. The hospital was closed in Yambuku as the epidemic expands.
On October 3, the Bumba region by the Minister of Health was quarantined. In late October, the epidemic was extended to eight villages.
At the time of the outbreak was the source of the disease with symptoms of hemorrhagic fever, headache, abdominal pain, nausea, vomiting, and hemorrhage, unknown. However, it was announced in October that the virus was related to the Marburg virus. Belgian and American scientists who worked in the area discovered that there was a new virus. They named the virus to nearby Ebola River.
Initially it was thought that the epidemic in Zaire does cause was the Ebola virus that was responsible for the epidemic in Sudan. A few years later, however, showed the Zaire Ebola virus, a type of the Ebola virus, responsible for this epidemic.
2007
In August 2007 the World Health Organization has identified an outbreak of Ebola in the Congolese province of West Kasai. At least 167 people would have died after being infected with the Ebola virus.
On 29 November 2007 it was announced that there has been an Ebola outbreak in Bundibugyo district in Uganda on 10 November. In this outbreak, it is a hitherto unknown variant of the virus. This new variant has the feature that he is less (external) causes bleeding, on the other hand it seems to be mainly a lethal variant by the fever which causes the virus. This new variant has so far 22 deaths.
2014
West Africa
The 2014 outbreak started in all probability by a boy of two and his mother from the Guinean region Guéckédou on 2 December 2013. In March 2014 killed 111 people in Guinea sure the virus and there are 127 registered infected. In neighboring Liberia were ending March 2014 adopted two infections with the virus. On April 10, 2014 it was determined that two people have been infected with Ebola in Morocco, suggesting that the virus spread further. In June 2014 it employed all 759 infections which 468 with a fatal outcome. On September 22, 2014, there were already 5843 infections, according to WHO, which contained 2803 patients are deceased. In Spain is a contagious missionary deceased from the disease. On 2 October 2014, the World Health Organization announced that the death toll had already risen to 3338 and the number of infection was already 7178. There are already more than 4,400 people deceased to Ebola. The actual number of infections is probably many times higher because not all cases can be registered due to the scale of the epidemic.
Congo
In August Ebola was found in a pregnant woman who had become ill after preparing bushmeat. She died on August 11th. By burial rituals the virus had a chance to spread. Research showed that this epidemic is not related to the Ebola outbreak in West Africa.
Ebola vaccination and medication
Antiviral drugs for people infected with Ebola are being developed. After the virus was in the United States in 1989 in monkeys found one is accompanied been looking for. After years of laboratory research is a vaccine found that in mice and probably also works in monkeys. However, this has not been tested in accordance with established procedures on people. Both Leiden company Crucell as Canadian Tekmira Pharmaceuticals far with the development of a vaccine. On August 12, the Canadian government gave to the WHO more than 1,000 doses of its experimental Ebola vaccine ESL EBOV. The vaccine had only been tested on monkeys. The firm Janssen stated on October 28, 2014 that she will produce one million vaccines from May 2015. Glaxo Smith Kline has now a vaccine that has been tested successfully on 20 volunteers, on the basis of the common cold virus of a chimpanzee which a non-contagious protein of the Ebola virus has been added. On January 23, 2015 it was announced that the trial will be continued on a larger scale in the affected areas in West Africa.
In early August 2014 it was known that two Americans, dr. Kent Brantly and Nancy Writebol, have been successfully treated with the experimental intravenous drug, a mixture of three monoclonal antibodies, which can be obtained after infection of mice through the tobacco plant Nicotiana benthamiana, called zmapp . The Spanish priest Miguel Pajares has been treated with the experimental agent. The drug was still in the testing phase in animals, but because of the severity of the disease still applied to three sick people and immediately looks to be promising. On August 12 dies the Spanish priest Miguel Pajares yet. He was already weakened before the medication was administered. On August 12, the company made known Mapp Bio small stock zmapp to send free to Liberia. Three local doctors there seemed to be successfully treated, but one of them is still deceased.
The TKM-Ebola means that the FDA earlier in 2014 banned apply in healthy volunteers, was released on August 7 for use in infected individuals. The drug interferes with the RNA-synthesis of the virus and thus prevents the production of disease-causing proteins.
Of the existing registered drugs clomiphene appeared promising in infected mice, as well as the related toremifene. Also, the non-registered favipiravir was effective against the virus in vitro and in studies with infected mice. It is being piloted in Guinea. It was found in February 2015 moderately effective, especially when not too heavily infected patients.
Also brincidofovir, a prodrug developed against other viruses and in Phase 3 study is being tried. In Liberia is used lamivudine with relative success. That agent is already registered with HIV infection.
There are no known cases of people who, after curing this virus a second time to become ill. Given the small number of infections per outbreak is not surprising. It is, however, will not be clear whether the human immune system itself in the long term can adequately protect against the virus, as is the case with an ordinary flu. Why are cases described of infected people who recovered after transfusion of blood of individuals who had previously survived the disease. Liberia is in November 2014, according to WHO such serum ready to use. In Guinea, the Institute of Tropical Medicine in Antwerp research with antibodies from the blood of patients cured.