Ebola Virus

Ebola or Ebola Hemorrhagic Fever is a human viral disease caused by the Ebola virus. The disease is rare and occurs in the form of regional outbreaks in Central African countries. The name Ebola comes from the river of the same name in Congo (then Zaire) where a second outbreak occurred in 1976 and Ebola was first recognized and demonstrated by Guido van der Groen and Peter Piot in the town of Yambuku, located 95 kilometers from the river the Ebola. The condition causes a high death rate and no specific treatment or drug is yet available against the virus.

Symptoms and Disease

The incubation period for Ebola is 2 to 21 days. Usually the patient develops the first symptoms after 7 days. After the first symptoms - fever, very severe headache and strong pain shoots - appear, the disease can get worse quickly. An atypical but serious symptom is hiccups, which affect 15% of patients.

In the early stages of the disease, the patient will show nonspecific flu - like symptoms, such as sore throat, fever, and general malaise. These symptoms come on quickly and worsen quickly. Head, muscle and joint pain, fever with chills, loss of appetite and a feeling of weakness are the most common early symptoms.

A blotchy rash sometimes appears around day five of the infection, mainly on the trunk. This result is not very characteristic as it only occurs in about 15% of the cases. Then gastrointestinal complaints such as abdominal pain, vomiting and diarrhea. Signs of damage and bleeding of the mucous membranes are: conjunctivitis, difficult and painful swallowing and bleeding in different places of the gastrointestinal tract. Bleeding from the mucous membranes occurs in half of the cases. In subsequent stages, further bleeding, inflammation of the heart muscle and pulmonary edema may occur.

In the second week of illness, one usually sees the beginning of recovery or a further deterioration with diffuse blood clotting in the vessels, general organ failure and shock. When the patient dies from the infection, it usually happens in the second week. Recovery takes a long time. During this period, one sees regularly complications such as orchitis, liver inflammation, joint pain, inflammation of spinal or bone marrow and conjunctivitis.

Infections

The virus is transmissible through all bodily fluids. The version that occurs in Congo-Kinshasa can probably be spread through direct contact with the patient, through nursing, or contact with the dead body. Not everyone who is infected with the virus dies from this, the mortality rate is estimated to be around 50%. In all likelihood, individual factors such as health and genetic predisposition play a role in susceptibility to the virus. Ebola was first scientifically registered in 1976. Since that outbreak and until the 2014 outbreak, there have been about twenty different smaller outbreaks. Until the outbreak of the disease in West African in 2014countries Guinea and Liberia several hundred people died per outbreak. Nevertheless, the Ebola virus became the subject of discussion for months when another outbreak occurred in Congo in Kinshasa in 1995. In early 2005, an Ebola outbreak occurred in Etoumbi.

Bats are the most likely source of filoviruses. The viruses have been found in several bat species that live in Africa. They spread the virus through their feces, among other things. Several animals in the African tropical rainforest can be infected with the virus, such as chimpanzees, gorillas and antelopes. If people slaughter and eat these animals, they can also get the virus. Bats are eaten around Meliandou, the village of the first patient in Guinea.

The virus appears to be able to survive in the male germ cells for a longer period: viruses were still found in the sperm in infected men months after the infection (in one case even after 565 days). There are therefore persons infected after sexual intercourse with an ebola-cured man.

Epidemics

1976

The first documented epidemics occurred in Sudan and Zaire in 1976.

Sudan

In the period June to November 1976 broke an Ebola epidemic in cities Nzara, Maridi, Tembura and Juba in southern Sudan out. The outbreak started in a cotton factory in Nzara where the first patient fell ill on June 27, 1976, who died on July 6. This patient's colleagues also became ill, after which the disease spread to family members and health professionals. The epidemic spread strongly in a hospital in Maridi in August. The care of the sick probably played a role in this. Because many staff also fell ill, panic broke out among the patients and the staff present, so that the hospital was largely abandoned. The last contamination was recorded on November 25, 1976.

During this outbreak, 284 victims were registered, 151 of whom died. The cause of the contamination was the contact between people and pests in the cotton factory, such as the black rat, bats, the Tadarida trevori and mosquitoes.

This epidemic was initially believed to be the likely source of the outbreak of the disease in Zaire in the same year. Argument for this was the strong mobility of people between Nzara and the Bumba region of Zaire. Years later, however, it turned out to be two separate species of the Ebola virus, with the Sudan Ebola virus being responsible for this epidemic.

Zaire

In the north of what was then Zaire, present - day Congo-Kinshasa, an epidemic of Ebola broke out between September 1 and October 24, 1976. 318 infections, of which 280 deaths, were registered.

The epidemic started in the Bumba region of the Equator Province, near the city of Yambuku 95 km south of the Ebola River. The first patient, a 44-year-old teacher at a mission school, fell ill on September 1 after receiving an injection of chloroquine against malaria on August 26 in a hospital of the Belgian mission in Yambuku. Others also became ill after these injections or after direct contact with other infected patients. Therefore, it was believed that lack of hygiene played a role in the spread of the disease. The first patient had infected the needle, with which others were subsequently injected in the context of vaccination. At the end of September, a Belgian sister also fell ill. She is taken to a hospital in Kinshasa. The hospital in Yambuku will be closed as the epidemic continues to spread.

On October 3, the Bumba region was quarantined by the Minister of Health. At the end of October, the epidemic had spread to eight villages.

At the time of the epidemic, the source of the disease with symptoms of haemorrhagic fever, headache, abdominal pain, nausea, vomiting and bleeding was unknown. It was announced in October that the virus was related to the Marburg virus. Belgian and American scientists working in the area discovered that there was a new virus. They named the virus after the nearby Ebola River.

It was initially thought that the epidemic in Zaire was caused by the Ebola virus responsible for the epidemic in Sudan. A few years later, however, Zaire Ebola virus, a type of Ebola virus, was found to be responsible for this epidemic.

2007

In August 2007, the World Health Organization WHO noted an outbreak of Ebola in the Congolese province of West Kasai. At least 167 people are believed to have died after being infected with the Ebola virus.

On November 29, 2007, it was announced that an Ebola outbreak had occurred on November 10 in the Bundibugyo district of Uganda. This outbreak involved an unknown variant of the virus, which was unknown in 2010. This new variant has the characteristic that it causes less (external) bleeding. On the other hand, it seems to be mainly a deadly variant due to the fever that the virus causes. 66 were killed by this new variant (May 2019).

2014

West Africa

The 2014 outbreak most likely started in a boy of two and his mother from the Guéckédou region of Guinean on December 2, 2013. In March 2014, at least 111 people died in Guinea from the virus and 127 registered infected. Two infections with the virus were also detected in neighboring Liberia at the end of March 2014. On April 10, 2014, two people were found to be infected with Ebola in Morocco, indicating that the virus had spread further. In June 2014, there were already 759 infections, 468 of which were fatal. According to the WHO, on September 22, 2014, 5843 infections were already known, of which 2803 patients died. In Spain, an infected missionary died from the disease. On October 2, 2014, the World Health Organization announced that the death toll had already risen to 3,338 and the contamination rate was already 7,178. In total, 11,301 people died from Ebola, including in Guinea (2536), Sierra Leone (3956) and Liberia (4809) and 15 more in other countries (CDC, Feb 17, 2016). The number of infections is probably many times higher, because not all cases can be registered due to the magnitude of the epidemic.

Congo

In August, Ebola was diagnosed in a pregnant woman who became ill after preparing bushmeat. She died on August 11. Funeral rites saw the virus spreading. Research showed that this epidemic is unrelated to the Ebola outbreak in West Africa. In total 49 died.

2018-2020

Another Ebola outbreak occurred in eastern Congo in 2018. The disease mainly prevailed in the border region with Uganda and Rwanda. The number of deaths was about 100 on September 24 of that year. On July 17, 2019, the death toll was at least 1,582 people and the WHO declared the outbreak a medical emergency "of international concern". The reason was an Ebola death in the metropolis of Goma, a border town with Rwanda, 200 km from the original source of infection. At the time, there had already been three cross-border deaths in Uganda.

On December 13, 2019, the death toll was 2,207. On 20 January 2020, this had increased slightly to 2,236.

Vaccination and Medication

Antivirals for people infected with Ebola are under development. After the virus was detected in monkeys in the United States in 1989, they were searched for. After years of laboratory research, a vaccine has been found that works in mice and probably also in monkeys. However, this has not yet been tested on humans according to established procedures. Both the Leiden company Crucell and the Canadian Tekmira Pharmaceuticals is far from developing a vaccine. On August 12, the Canadian government gave the WHO over 1,000 doses of its experimental Ebola vaccine VSV-EBOV. The vaccine was only tested on monkeys. On October 28, 2014, the Janssen Company stated that it will produce one million vaccines from May 2015. GlaxoSmithKline now has a vaccine that has been successfully tested on 20 volunteers, based on a chimpanzee cold virus to which a non-infectious Ebola virus protein has been added. On 23 January 2015, it was announced that the trial will continue on a larger scale in the affected areas in West Africa. Ultimately, the Merck vaccine was tested on 4,000 potentially infected volunteers and was found to be 100% effective when administered on time.

In early August 2014, it was announced that two Americans, Dr. Kent Brantly and Nancy Writebol, had been successfully treated with the experimental intravenous drug, a mixture of three monoclonal antibodies, which can be obtained from the Nicotiana benthamiana tobacco plant after infection by mice, called ZMapp. The Spanish priest Miguel Pajares has also been treated with the experimental drug. The drug was still in the testing phase in animals, but has been applied to three critically ill people due to the severity of the disease and appears to be immediately promising. On August 12, the Spanish priest Miguel Pajares dies. He was already severely debilitated before the drug was administered. On August 12, the company Mapp Bio announced that it would ship the small stock of ZMapp to Liberia free of charge. Three local doctors seemed to have been successfully treated there, but one of them died.

The drug TKM-Ebola, which the FDA banned from applying to healthy volunteers earlier in 2014, 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 pathogenic proteins.

Of the pre-existing registered drugs, clomiphene showed promise in infected mice, as did the related toremifene. The unregistered favipiravir was also effective against the virus in in vitro studies and in infected mice. It is being tried in Guinea. It was found to be moderately effective in February 2015, especially in moderately infected patients.

Also brincidofovir, a prodrug developed against other viruses, in Phase 3 trial, was tried in 2014 and 2015, but the responsible pharmacist continued this experimental phase silent because too few subjects with Ebola. Lamivudine has been used with relative success in Liberia. This drug is already registered with HIV infections.

There are no known cases of people who have become ill a second time after this virus has been cured. This is not surprising given the low number of infections per outbreak. However, it is not clear whether the human immune system can protect itself sufficiently against the virus in the long term, as is the case with ordinary flu. However, cases have been described of infected persons who recovered after blood transfusions with blood from fellow sufferers who had previously survived the disease. In Liberia, such a serum will be ready to use in November 2014, according to WHO. In Guinea, the Institute of Tropical Medicine in Antwerpa study with antibodies from blood from cured patients.

In August 2019, it was announced that Ridgeback Biotherapeutics, a Florida company, would have a working drug against Ebola.