Symptoms and signs of the Ebola virus. The spread of the Ebola virus

Ebola fever refers to a group of viral fevers, in which there is clearly expressed hemorrhagic syndrome. Today it is one of the most dangerous virus diseases, since it has a very high mortality rate. But beyond that, the threat is that little is known about him. Ebola fever (symptoms, treatment, causes, signs of the disease) is investigated at the international level.

History and geography of the Ebola virus

The Ebola virus is most prevalent in the zone of tropical forests, where high humidity. Epidemiological foci are in Central and West Africa - in Sudan, Zaire, Gabon, Nigeria, Senegal, Cameroon, Kenya, Ethiopia, Central African Republic, Liberia. Outbreaks of Ebola epidemic here occur in summer and spring.

The disease caused by the Ebola virus was first recorded in the Zaire region of the same name. Signs of the Ebola virus from local residents arose in 1976. At the same time, it was possible to isolate the causative agent of this new infection from the blood of one of the deceased. From 1976 to 1979, many cases of this disease have been documented and described in Zaire and Sudan. Later, in 1994-1995, the virus returned again, and a new wave broke out in the same Zaire, taking hundreds of citizens with them. The lethal outcome reached the infected in 53-88 percent of cases.

In 1996, the fever spread to the territory of Gabon. Later, according to a retrospective screening among the population of other African countries, the researchers came to the conclusion that back in the 1960s the spread of the Ebola virus occurred in Nigeria, Ethiopia and Senegal. From December 1994 to June 1995 in Zaire, a new outbreak of Ebola fever arose. The reason for this was the use of local people to eat monkey brains. As it turned out, animals were virus carriers. In total, then, about 250 people became ill, 80 percent of whom died.

Spread of the epidemic

Initially, signs of the Ebola virus arose in the workers of a cotton factory in the city of Nzara. They extended it to other residents, including members of their families and people who were in contact with them. In the same state, only in the city of Maridi, as well as in Zaire, the spread of the disease occurred directly within the walls of hospitals. Here they played the role of catalysts because of the low knowledge of the virus at that time. The patients were delivered with an unknown fever, it quickly spread to the personnel who contacted the blood and secretions of the patients. And also transferred to other patients through manipulation tools that were not sufficiently disinfected.

Family members of patients became secondary foci of infection. They, leaving hospitals and not realizing that they themselves already carry the virus, living with the carriers for a while, spread it further. Only later did it become known about the routes of transmission of the causative agent of the Ebola fever. Infection often occurred even when manipulating already dead people, for example, during funeral ceremonies.

The last flash

The epidemic for 30 years periodically appeared and died down again, carrying with it a significant number of victims. The Ebola virus managed to inflict damage on thousands of human lives throughout Central Africa. If the epidemics of previous years affected not so much territory and population, then the last outbreak in the summer of 2014 carried with it more than 900 lives out of 1,700 infected. Of course, if you take into account the population of the whole planet, this number does not look so horrifying. But for small communities and African townships this has become a real pestilence. Despite all the efforts of Nigerian doctors to contain the spread of the virus, new and new cases of infection became known almost every day, and its geography expanded to Côte d'Ivoire and Sierra Leone.

Sources of infection

The source of the infection as such is not fully understood to this day. There are assumptions that rodent can serve as its reservoir. The carriers are also monkeys. In the animal world, the bats of the Ebola virus are also considered to be bats. They transmit it to other inhabitants of the fauna - antelopes and primates. Throughout Central Africa, there is an active trade in meat of wild animals, which, of course, does not pass any sanitary and epidemiological checks for signs of the Ebola virus. Thus, a single carcass, which is its carrier, could provoke another outbreak of the disease.

If a person is infected with this virus, it becomes dangerous to others, as the spread of the Ebola virus occurs very quickly. In practice it is known about cases when from one person there were up to eight consecutive transmissions. In this case, people who become infected first, as a rule, die. Further down the chain, mortality decreases. The virus can develop completely in different organs and tissues. It is detected in the blood 7-10 days after infection. Also, its presence can be determined in the secretions of the human body - urine, nasal mucus, sperm.

Transmission paths

Since the onset of the disease, as soon as the first signs of the Ebola virus appeared, and within three weeks the patient is most dangerous to others. The transmission of a fever from one patient to another occurs in a variety of ways. So, many cases of infection through contact with the blood of the patient, sexually. Even through the use of common objects in everyday life, utensils, personal hygiene means is very high risk of infection.

But in most cases this happens when you directly contact infected people. Short-term contact with a sick person leads to infection in 23 percent of cases. In close and prolonged communication, transmission and signs of infection with the Ebola virus are noted in more than 80 percent. The virus penetrates the body, getting on the mucous membrane and even the skin of a person. According to observations, infection by airborne droplets does not occur, since the contactless presence in the same room with patients did not lead to transmission of the virus to the healthy. Despite these observations, the exact mechanism of transmission is unknown, as are all the primary signs of the Ebola virus.

Risk group

Infected blood is the most dangerous, because medical personnel are always at high risk during treatment and care of patients. It is very important not to have physical contact with infected and their physiological materials.

If you consider that the virus is carried by monkeys, then people who are engaged in their catch and transportation, especially during the quarantine period, are also at risk of being infected. There are cases of infection with the Ebola virus inside research laboratories, where they worked with green monkeys.

Due to the high rate of spread of the virus, as well as the variety of modes of transmission, the migration of people from Africa to other countries, as well as the transport of animals that may be carriers of the disease, is a great danger.

The causative agent of Ebola fever

The causative agent of the disease is the virus of the genus Filovirus, which belongs to the family Filoviridae. It is an RNA-genomic virus, which today has 5 strains that differ in their antigenic structure - Sudan, Zaire, Renston, Tai Forest and Bundibugyo. His reproduction occurs in the lymph nodes and spleen. After this, the cells of the internal organs begin to damage the virus itself and the autoimmune reactions of the body to it. In the incubation period the virus does not spread.

The onset of the disease is characterized by impaired microcirculation and rheological properties of blood, capillarotoxicosis, hemorrhagic and DIC syndromes. There are pathological changes in internal organs, focal necrosis of tissues. Ebola virus signs of the disease can have both in hepatitis, pancreatitis, pneumonia, orchitis and other diseases. Immune reactions are reduced, while antibodies against the virus in the body begin to appear mainly after complete recovery.

Ebola virus: signs of disease

What are the typical signs and symptoms of Ebola virus infection ? The incubation period has a very extended amplitude and is asymptomatic. Cases are described from several days to 2-3 weeks. Its end comes when the acute disease begins. This is evidenced by a sharp increase in body temperature to 38-39 degrees, headache, nausea, malaise, arthralgia and myalgia. In the early days, signs and symptoms of Ebola's disease may resemble angina, during which tonsils become inflamed and a feeling of a painful lump in the throat.

With the development of fever, these symptoms are accompanied by continuous vomiting, diarrhea, which has a hemorrhagic character, and pain in the abdomen. Soon the hemorrhagic syndrome develops, which is accompanied by skin hemorrhages, bleeding within the organs, vomiting with blood. In this case, there are often cases of aggressive behavior and extreme excitability of patients, which persist for a long time and after recovery. Also in half the cases, after 4-6 days after the onset of the disease, there are manifestations of exanthema, which has a draining character.

Diagnostics

As there are no clinical signs of Ebola as such, it develops very quickly, differential diagnostics has difficulties. It can be diagnosed laboratory by PCR, ELISA, as well as immunofluorescent methods. Very effective studies of serological reactions. But all this is available only in modern laboratories with good equipment and anti-epidemic regimen. Of course, in the field, this is not possible. Without the necessary equipment and professional staff, laboratory diagnostics is reduced to a complex one using immunoenzyme test systems that detect antigens and antibodies of the Ebola virus.

Death

The main cause of death during a fever outbreak are bleeding, intoxication, and also shock caused by these phenomena. The greatest number of deaths occurs in the second week of the disease. When the skin is covered with blisters, bleeding from the ears, eyes, mouth opens, internal organs begin to refuse, the worst thing is death. Ebola kills quickly, but painfully. If the patient has a chance to recover, the acute phase can last up to 2-3 weeks, and the convalescence can be up to 2-3 months. The survivors of the Ebola fever during this period suffer from severe weight loss, anorexia, hair loss and even mental disorders.

Because of the similarity of the first symptoms of Ebola to a number of other diseases, very often in the early stages the virus can not be diagnosed and simply ignored. And this is a missed time and, as a result, a fatal outcome. Therefore, doctors are always in a state of readiness. The first days are the most critical, the survival of the patient depends on them, or rather on whether the body will be able to quickly develop antibodies that will help restore it. If this does not happen within 7-10 days, a person dies.

Treatment

The danger of Ebola fever is that there is still no effective cure for it. Treatment is carried out exclusively in specialized infectious departments, where patients are in strict isolation. Methods of symptomatic therapy, as well as pathogenetic measures, are used. But, as practice shows, in most cases these methods of treatment do not bring great results and are ineffective. Positive dynamics shows the use of plasma convalescent. Etiotropic therapy for the treatment of Ebola fever for today does not exist.

If Ebola hemorrhagic fever is detected, the patient is immediately placed in a box-type hospital where a strict sanitary regime is observed. The discharge occurs after recovery, but not earlier than on the 21st day after the onset of the acute course of the disease. This happens when the patient's condition returns to normal, and virological studies show negative results. Everything, that the patient uses and with what it contacts, passes a thorough disinfection in the box, where it is stored. Chambers of patients are equipped with a special exhaust system, in which only one-way air supply is provided, inside the box.

During the treatment, only one-time instruments are used, which are destroyed after application. The medical staff is in protective anti-plague suits, as are relatives who care for the sick. Studies of blood and secretions of Ebola infected with fever, as well as all laboratory work, are performed with the utmost care and at the highest level of sterility.

Prevention

People who stayed in contact with patients and could get infected are also placed in boxes for up to 21 days for observation. With minimal suspicion of the possibility of the disease, patients are administered immunoglobulin, which is specially developed from the serum of hyperimmunized horses. This drug is valid for 7-10 days.

It is also important that even with a pure blood test, Ebola virus can still be in the body for a long time, up to three months. For example, in the breast milk of women and the sperm of men. Therefore, even having coped with the disease, they are recommended to give up breastfeeding so as not to infect the child, and to practice protected sex. After curing from Ebola fever, the body produces a very persistent immunity. Re-infection occurs very rarely and does not reach 5 percent.

Control over the spread of hemorrhagic fevers is carried out at the international level. To this type of diseases are the fevers of Ebola, Lassa and Marburg. Therefore, all countries are obliged to report in a timely manner on massive and even single cases to the WHO headquarters in order to immediately begin preventive measures and prevent an epidemic. Fundamental studies of the Ebola virus made it possible to work on the creation of a vaccine against it, as well as protective preventive drugs. Also, there is a constant mass notification of citizens about what is Ebola fever. Causes, symptoms of the disease, how to avoid it, what to do in case of infection, everyone should now know. To prevent infection and spread of the virus, tourists are not recommended to visit African countries, where their outbreaks are recorded.

Drug development

As the Ebola virus appeared singly in African villages and soon faded, pharmaceutical companies were not particularly interested in the development of a vaccine against it because of the unprofitableness of the given undertaking. But the governments of many countries estimated the severity of this virus, so they did not spare the multibillion investments in his research. Conducted experiments on monkeys showed good results after the use of developed vaccines. They blocked the virus, and even managed to cure several primates. But the low interest of the pharmaceutical industry is still an obstacle to the large-scale production of funds from the Ebola virus.

Before the development of the vaccine, patients were given painkillers and antibiotics to stop the fever, to keep the immune system and prevent the development of complications. Palliative treatment of liquids with electrolytes was also used. Serum learned to receive from the blood of animals. They were infected with a virus and waited for the production of antibodies. This method led to an improvement in the condition of patients. But there is no licensed vaccine against the Ebola virus until today.