Ebola haemorrhagic fever

Ebola haemorrhagic fever is an acute viral especially dangerous infectious disease, characterized by severe course, marked hemorrhagic syndrome and high level of lethality. The synonym is Ebola.

ICD-10 code

A98.4. Disease caused by the Ebola virus.

Epidemiology of Ebola haemorrhagic fever

The reservoir of the Ebola haemorrhagic fever virus is the rodents inhabiting human habitation. Cases of infection are revealed at the opening of the corpses of wild chimpanzees and when eating monkeys' brain. A sick person is a great danger to others. Mechanisms of transmission of the pathogen: aspirating, contact, artifical. Transmission ways: airborne, contact, injection. The virus is found in the blood, saliva, nasopharyngeal mucus, urine, semen. Infection of people occurs when caring for the sick; in domestic conditions through the hands and household items, contaminated with blood and urine of the patient: through medical instruments and, possibly, sexually. The risk of intrafamily infection is 3-17%, with a nosocomial form - more than 50%. The transmission of the virus from person to person in 5 generations is described, and in the first generations the lethality reaches 100%.

The susceptibility of people to the Ebola virus is high: it does not depend on age and sex. Postinfectious immunity is relatively stable. Repeated cases of the disease are rare (no more than 5% of convalescents are detected). In endemic areas, 7-10% of the population has antibodies to the Ebola virus, which indicates the possibility of developing subclinical or erased forms of the disease.

The distribution of the virus is Central and West Africa (Sudan, Zaire, Nigeria, Liberia, Gabon, Senegal, Cameroon, Ethiopia, Central African Republic). Flashes of Ebola hemorrhagic fever occur mainly in spring and summer.

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What causes Ebola haemorrhagic fever?

Ebola hemorrhagic fever is caused by Ebolavirus genus Marburgvirus family Filoviridae - one of the largest viruses. Virion has a different form - filiform, branching. Arachnid, its length reaches 12 000 nm. The genome is represented by a single-stranded negative RNA surrounded by a lipoprotein membrane. The virus contains 7 proteins. The Ebola and Marbourg g viruses are similar in their morphology, but differ in their antigenic structure. Antigenic properties of glycoproteins (Gp) distinguish four serotypes of the Ebola virus, three of them cause different severity in people in Africa (Ebola-Zaire-EBO-Z, Ebola-Sudan-EBO-S and Ebola-Ivory Coast-EBO-CI ). Manifest cases of Ebola-Reston virus (EBO-R), highly pathogenic for monkeys, have not been identified in humans.

The virus is highly variable. Passaged in the culture of guinea pig cells and Vero with a weakly expressed cytopathic effect.

Ebolavirus has an average level of resistance to damaging environmental factors (pH, humidity, insolation, etc.).

Pathogenesis of Ebola haemorrhagic fever

Entrance gate for the pathogen - mucous membranes and skin. Ebola haemorrhagic fever virus enters the lymph nodes and spleen, where it replicates with the development of intensive viremia in the acute period of the disease with multiple organ dissemination. As a result of direct exposure to the virus and autoimmune reactions, there is a decrease in platelet production, damage to the endothelium of the vessels and internal organs with foci of necrosis and hemorrhage. The greatest changes occur in the liver, spleen, lymphoid formations, kidneys, glands of internal secretion, the brain.

Symptoms of Ebola haemorrhagic fever

The incubation period of Ebola hemorrhagic fever lasts 2-16 days (an average of 7 days).

The onset of Ebola hemorrhagic fever is sudden with a rapid rise in body temperature to 39-40 ° C, intense headache, weakness. Symptoms of Ebola haemorrhagic fever are as follows: severe dryness and sore throat (sensation of "rope" in the throat), pain in the chest, dry cough. On the 2-3th day there are pains in the abdomen, vomiting, diarrhea with blood (melena), leading to dehydration. Since the first days of the course of the disease, amyimicity of the face and sunken eyes are characteristic. On the 3rd-4th day there are severe symptoms of Ebola hemorrhagic fever: intestinal, gastric, uterine bleeding, bleeding of the mucous membranes, hemorrhages at the injection and skin lesions, conjunctival hemorrhage. The hemorrhagic syndrome is rapidly progressing. On the 5th-7th day, part of the patients (50%) have a corneal rash, followed by skin peeling. Identify inhibition, drowsiness, confusion, in some cases - psychomotor agitation. Death occurs on the 8th-9th day from massive blood loss and shock. With a favorable outcome, the febrile period lasts 10-12 days; recovery slow for 2-3 months. During the reconvalescence period, pronounced asthenia, anorexia, cachexia, hair loss, trophic disorders, mental disorders are observed.

Complications of Ebola haemorrhagic fever

Ebola hemorrhagic fever is complicated by infectious-toxic shock, hemorrhagic and hypovolemic shock.

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Diagnosis of Ebola haemorrhagic fever

Diagnosis of Ebola hemorrhagic fever is complex, as there are no specific symptoms of the disease. Ebola fever should be assumed in cases of acute development of febrile illness with multiple organ lesions, diarrhea, neurologic and expressed hemorrhagic manifestations in a patient who was in endemic area or in contact with similar patients.

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Specific and nonspecific laboratory diagnostics of Ebola haemorrhagic fever

Specific laboratory diagnosis of Ebola hemorrhagic fever is carried out by virological and serological methods. Isolation of the virus from the blood of patients, nasopharyngeal mucus and urine is carried out by infecting cell cultures; with an electron microscopic examination of skin biopsy specimens or internal organs. Applied PCR, ELISA, RNIF, RN, RSK, etc. All the studies are carried out in special laboratories with IV level of biological safety.

Nonspecific laboratory diagnostics of Ebola hemorrhagic fever includes the conduct of a general blood test (typical: anemia, leukopenia, followed by leukocytosis with neutrophilic shift, the presence of atypical lymphocytes, thrombocytopenia, decreased ESR): a biochemical blood test (increased activity of transferases, amylase, azotemia); definition of coagulogram (characteristic hypocoagulation) and acid-base state of blood (identify signs of metabolic acidosis); conducting a general urine test (expressed proteinuria).

Instrumental diagnosis of Ebola haemorrhagic fever

Radiography of the chest, ECG, ultrasound.

Differential diagnosis of Ebola haemorrhagic fever

Differential diagnosis of Ebola fever is extremely difficult, since similar clinical manifestations in epidemiological foci are found in patients with Marburg fever, Lassa fever, yellow fever, as well as in patients with septicemia, malaria, typhoid and other diseases. In connection with this, the data of virological, electron microscopic and serological studies are of diagnostic importance; negative results of conventional bacteriological and parasitological studies, as well as the lack of effect from the use of antibiotics, antimalarials and other chemotherapeutic drugs.

The clinical picture of yellow fever is also characterized by an acute onset, marked intoxication with the development of thrombohemorrhagic syndrome. Differential diagnosis of Ebola fever takes into account the following data: stay in endemic area no more than 6 days before the development of the disease; presence of a two-wave fever, insomnia; the swelling of the eyelids, the puffiness of the face ("amarilla mask"); in the blood - neutropenia, lymphopenia.

Ebola fever is differentiated from a number of infectious diseases with hemorrhagic syndrome. In the first 1-3 days of the disease before the development of hemorrhagic manifestations, the clinical picture of fever is similar to the severe form of influenza with acute onset, headache, high fever, injection of vessels of sclera and leukopenia in the blood. However, with Ebola fever, the symptoms of CNS involvement are more pronounced, often diarrhea and vomiting occur, and rarely catarrhal phenomena develop.

The acute onset of the disease, severe intoxication, hemorrhagic syndrome is characteristic of both Ebola and leptospirosis fever. But it is not characterized by cough, pain in the chest and abdomen, vomiting, diarrhea, and leukopenia.

There is no difficulty in differential diagnosis of Ebola with "non-infectious" haemorrhagic disease - haemophilia, characterized by sharp bleeding, manifested by external and internal bleeding with minor injuries, joint bleeding, and absence of thrombocytopenia.

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Indications for consultation of other specialists

Consultations of a hematologist, neurologist, gastroenterologist and other doctors are shown when conducting differential diagnosis with diseases that occur with a similar clinical picture or aggravate the course of hemorrhagic fever.

Indications for hospitalization

Ebola fever is an occasion for emergency hospitalization and strict isolation in a separate box.

Treatment of Ebola haemorrhagic fever

Etiotropic treatment of Ebola hemorrhagic fever has not been developed.

Pathogenetic treatment of Ebola haemorrhagic fever

In the epidemic focus recommended the use of plasma convalescent. The main treatment for Ebola hemorrhagic fever is the use of pathogenetic and symptomatic drugs. Combating intoxication, dehydration, bleeding. Shock are carried out by conventional methods.

Diet and diet

The patient needs strict bed rest and 24-hour medical supervision.

The diet corresponds to table number 4 according to Pevzner.

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Approximate terms of incapacity for work

Considering the severity of the disease, convalescents are considered incapacitated for 3 months after discharge from the hospital.

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Clinical examination

Ebola haemorrhagic fever does not require a dispensary observation for those who are sick.

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Memo for the patient

Recommended nutrition with the use of easily assimilated products, without special restrictions; compliance with the physical regime.

How is Ebola haemorrhagic fever prevented?

Specific prophylaxis of Ebola hemorrhagic fever

Specific prophylaxis of Ebola hemorrhagic fever is not developed.

Nonspecific prevention of hemorrhagic fever Ebola

Nonspecific prophylaxis of Ebola haemorrhagic fever consists in isolation of patients in special departments or ward-insulators, preferably in special plastic or glass-metal insulating booths with autonomous life support. For transportation of patients use special transport insulators. Medical personnel should work in individual protective equipment (respirators or gauze masks, gloves, goggles, protective suit). It is necessary to strictly adhere to the sterilization of syringes, needles, and instruments in medical institutions.

Ebola hemorrhagic fever is prevented with the help of a specific immunoglobulin obtained from the serum of immunized horses (the method was developed at the Virology Center of the Scientific Research Institute of Microbiology).

In the outbreaks of all patients, they isolate, establish medical supervision and control over the contactees.

The most important preventive measure preventing the introduction of hemorrhagic fever from endemic areas is the implementation of the International System of Epidemiological Surveillance.

What prognosis is Ebola haemorrhagic fever?

Ebola haemorrhagic fever has a serious prognosis. In diseases caused by EBO-S and EBO-CI, lethality reaches 50%, EBO-Z - 90%. If the outcome is favorable, the recovery is prolonged.

Mortality and causes of death

Mortality is 50-90%. Causes of death: infectious-toxic shock, hypovolemic shock, DIC-syndrome.