Ebola virus disease
Introduction
Introduction to Ebola virus disease Ebola virus disease is an acute hemorrhagic infection caused by the Ebolavirus (EBOV) of filoviridae. It is mainly transmitted through the patient's blood and excretion. The main clinical manifestations are acute onset, fever, myalgia, hemorrhage, rash and liver and kidney dysfunction. basic knowledge The proportion of illness: this disease is rare, the incidence rate is about 0.0001% - 0.0002% Susceptible people: no specific people Mode of transmission: blood transmission, contact transmission Complications: Myocarditis, pneumonia, orchitis
Cause
Ebola virus disease etiology
Causes:
The virus is a linear body of varying lengths, 70-90 nm in diameter, 0.5-1400 nm in length, containing an inner spiral shell with a diameter of 40 nm, mostly in the form of branches. The viral genome is a single-stranded negative-strand RNA, about 19 kb long. It encodes seven nuclear structural proteins, including VP3VP40, VP30, VP24, glycoprotein (GP) and RNA polymerase. The GP gene has unique coding and transcriptional functions for EBOV replication, and the virus replicates in the cytoplasm of infected cells. It is released in a budding manner. However, the specific steps of the virus replication are still unclear. The outer membrane of the virus is composed of lipoproteins. The membrane has a 10 nm long brush-like projection, which is a viral glycoprotein. The virus can infect a variety of mammals. Animal cells grow well in Vero-E6 cells and can cause cytopathic effects. Ebola virus is mainly divided into four subtypes: Zaire (EBOV-Z) and Sudan (EBOV-S). , Côte d'Ivoire (EBOV-C) and Reston (EBOV-R), different subtypes have different characteristics, of which Zaire is the most toxic, followed by Sudan, both for humans and non-human primates The mortality rate of the class is very high, and the virulence of the Reston and Côte dIvoire types is higher. , Manifested as subclinical infection, but lethal for non-human primates.
Pathogenesis:
EBOV is a pan-tropic virus that invades various system organs, especially liver and spleen damage. The occurrence of this disease is related to the level of immune response in the body. IL-2, IL-10, TNF- in serum of patients. The levels of , IFN- and IFN- are significantly increased. The mononuclear phagocytic system, especially the phagocytic cells, is the first target cell to be attacked by the virus. Subsequently, both fibroblasts and endothelial cells are infected, and the vascular permeability is increased. The protein was precipitated. The virus was first detected in the lungs 2 days after infection, and was detected in the liver, spleen and other tissues 4 days later, and the whole body tissues were detected after 6 days.
The main pathological changes of this disease are mononuclear phagocytic system involvement, thrombosis and hemorrhage, extensive necrosis of systemic organs, especially liver, spleen, kidney, and lymphoid tissues.
Prevention
Ebola virus disease prevention
At present, it is controversial to produce protective neutralizing antibodies against individuals who can induce Ebola virus infection. The prevention is mainly to isolate patients, and the secretions, excretions and used items of patients should be thoroughly disinfected. Medical personnel must be strict. With the implementation of protective measures, the Ebola virus may have new, more virulent variants due to natural selection and may cause a global pandemic through aerosol transmission. In order to obtain high titer antiviral immune serum, it has been obtained from animals such as sheep, goats and the like which are not sensitive to Ebola virus, and has protective effects on animals. After continuous processing and improvement, it can be developed for human beings in the near future. Immune products.
Complication
Ebola virus disease complications Complications Myocarditis pneumonia orchitis
Concurrent with myocarditis, pneumonia.
Symptoms of myocarditis: fatigue, fever, chest tightness, palpitations, shortness of breath, dizziness, severe heart failure or cardiogenic shock.
Signs of myocarditis: increased heart rate, disproportionate to elevated body temperature, enlarged heart, murmur, arrhythmia.
Pneumonia is characterized by fever, cough, phlegm and wheezing.
Symptom
Ebola virus disease symptoms Common symptoms Skin rash Myalgia fever with hemorrhage Joint pain, nausea, diarrhea, tinnitus, fatigue, abdominal pain
The disease is a multi-organ damage disease, mainly affecting the liver, spleen and kidney, the incubation period is 3 to 18 days. The main clinical manifestations are the onset of fever, fever, severe headache, sore muscles and joints, sometimes abdominal pain, onset 2 to 3 There may be nausea, vomiting, abdominal pain, diarrhea, mucus or bloody stools. Diarrhea can last for several days. The course of disease is 4 to 5 days into the extreme phase. The fever persists and changes in consciousness occur. Such as sputum and lethargy, this period of bleeding is common, and there may be hematemesis. , black stool, bleeding at the injection site, nose bleeding, hemoptysis, etc., pregnant women have abortion and postpartum hemorrhage, the course of 6 to 7 days can occur in the trunk of measles-like rash and spread to all parts of the body, a few days later desquamation, to the shoulder, palm More common in the soles of the feet, severe patients often die from bleeding, liver, kidney failure or serious complications on the 8th to 9th day of the disease, non-severe patients, gradually recovering 2 weeks after onset, most patients have asymmetric joint pain, May be migratory, mainly involving large joints, some patients with myalgia, fatigue, suppurative mumps, hearing loss or tinnitus, conjunctivitis, monocular blindness, uveitis, etc. Harm, in addition, also due to the persistence of the virus in the semen, causing orchitis, testicular atrophy, acute myocarditis complications, such as pneumonia.
Some people with asymptomatic infections in the EHF outbreak have EBOV IgG in their serum. Asymptomatic infections have little epidemiological significance, their virus levels are low, and they are cleared by the body's effective immune response in a short period of time. It can disappear quickly within 2 to 3 days, thus avoiding heat and tissue damage.
Examine
Ebola virus disease check
It can be seen that white blood cells and thrombocytopenia, prolonged prothrombin time and abnormal liver function, serum amylase is often elevated, proteinuria can occur, some cases have confirmed the presence of DIC, the diagnosis mainly depends on virus isolation and immunological examination, the first week of onset Blood is inoculated into guinea pig or Vero cells for the isolation of Ebola virus, serum-specific IgM, IgG antibodies can appear as early as 10 days, and IgM antibodies can persist for 3 months, which is a sign of recent infection. IgG antibodies can be sustained. It has been used for a long time, mainly for sero-epidemiological investigations. It also uses double-anti-sandwich method to detect viral antigens and PCR technology to detect viral nucleic acids. However, these tests must be performed in a P4 laboratory to prevent the spread of infection.
The virus can be found under electron microscopy, but the positive rate is low.
Diagnosis
Ebola virus disease diagnosis and identification
The diagnosis of this disease is mainly based on epidemiological data, clinical manifestations and laboratory tests. Must be differentiated from other viral hemorrhagic fever.
Viral hemorrhagic fever: a natural epidemic disease caused by a group of arboviruses. It is characterized by fever, hemorrhage and shock. These diseases are widely distributed in the world, and the clinical manifestations are more serious. The mortality rate is very high. High, more than ten kinds have been found in the world. Their pathogens, parasitic hosts and routes of transmission vary, and there are some differences in clinical manifestations, which are often prevalent in certain areas.
