Ebola virus a very rare virus, in 1976 in southern Sudan and the Democratic Republic of the Congo (DRC) (formerly known as Zaire) in the Ebola River region found its existence, causing widespread concern and attention of the medical community, "Ebola" thus named. Ebola" is a generic term used to refer to a group of viruses belonging to the genus Ebola in the family Fibroviridae. It is a virulent infectious virus that causes Ebola hemorrhagic fever in humans and primates, with a high mortality rate of between 50% and 90%, mainly due to stroke, myocardial infarction, hypovolemic shock, or multiple organ failure.
2, virus classification
Ebola virus has been identified in four subtypes, namely, Ebola-Zaire (EBO-Zaire), Ebola-Sudan (EBO-Sudan), Ebola-Leiston (EBO-R) and Ebola-C?te d'Ivoire (EBO-CI). Different subtypes have different characteristics. EBO-Z and EBO-S are highly pathogenic and lethal to humans and non-human primates; EBO-R is non-pathogenic to humans and lethal to non-human primates; EBO-CI is clearly pathogenic to humans but generally non-lethal, and is highly lethal to chimpanzees. magazine, it was reported that an Ebola virus called reston (EBO-R) has been identified in pigs on some farms in the Philippines, but unlike other types of Ebola, so far it has not posed a threat to humans.
a, Zaire type
Zairean Ebola virus has a lethality rate of up to 90%, with mortality rates in endemic areas of 88% in 1976, 100% in 1977, 59% in 1994, 81% in 1995, 73% in 1996, 80% in 2001-2002, 90% in 2003, and an 2007 averaged 83 percent.
The first outbreak occurred in the northern towns of the DRC on August 26, 1976, and the first case was recorded in Mabalo Lokela, a 44-year-old teacher, who was diagnosed with a high fever suspected to be malaria infection and was treated with quinine injections.
Shortly afterward, more patients sought medical attention with similar symptoms, including fever, headache, muscle pain, joint pain, fatigue, nausea and dizziness. These often develop into bloody diarrhea, severe vomiting and multiple hemorrhages, with initial transmission likely due to the reuse of unsterilized used syringes, and subsequent transmission primarily due to exposure to the virus while caring for the patient without proper safety precautions, or from the cleaning process of traditional pre-burial operations.
b, Sudanese
Sudanese Ebola was first identified in 1976 in a Sudanese cotton mill worker. The researchers pointed out that the worker should have been exposed to the carrier organism host in or near the factory, but after testing animals and insects near the factory there was still nothing, and the carrier host is still unknown. The second case was a nightclub owner living in Sudan, who was pronounced dead after local hospitals tried everything they could to treat him, but to no avail. Healthcare workers did not take proper precautions when treating him, leading to a major outbreak as the virus spread throughout the hospital. The most recent outbreak occurred in May 2004, when 20 cases were reported in Yambio County, Sudan, and five people died. The Bureau of Disease Control confirmed the cases as Sudanese Ebola a few days later, and neighboring countries such as Uganda and the Congo increased border guards to control the outbreak. the average mortality rate for Sudanese Ebola was 53% in 1976, 68% in 1979, and 53% in 2000-2001, for an average mortality rate of 53.76%.
c, Reston type
First found in November 1989 in crab-eating monkeys (Macacaascicularis) imported from the Philippines to Reston, Virginia, USA. This virus is highly lethal to monkeys but not to humans. in February 1990, Reston Ebola virus was again found in Reston, Texas and the Philippines. in 1992 and 1996, more cases were found in Tuscany, Italy, and in Texas. All infected monkeys showed symptoms similar to those of ape hemorrhagic fever. No humans were infected in either outbreak.
d, Ivorian type
This variety of Ivorian Ebola virus was first found in the Ta? National Park in C?te d'Ivoire. On November 1, 1994, two chimpanzee carcasses were found in the forest. Examiners found that the blood in the hearts was brown and liquefied (blood in a carcass should normally clot completely after ten hours or so of death), that there were no visible traces of internal organs, and that the lungs were full of blood. Tissues taken from the chimpanzees showed that the virus was very similar to Ebola in Sudan and to the 1976 Ebola outbreak in Zaire. After 1994, more dead chimpanzees were found and scientists tested the virus using many methods. The source of the infection was thought to be a colobus monkey that had been preyed upon by the chimps and had the virus.
One of the scientists who performed the autopsy contracted the virus. She developed dengue-like symptoms and was hospitalized in Switzerland a week later. She was discharged from the hospital two weeks later and made a full recovery in the sixth week after contracting the virus. [4]
c, mutated novel
Dr. Peter, an American scientist at the National Institute of Infectious Diseases and Allergy, believes that this may have been an infection caused by a mutation of the Ebola virus, which became easier to transmit than before.
3, transmission
Sensitive cells
Green monkey kidney cells (Vero), gopher kidney cells (BHK), human embryonic lung fibroblasts can be used to culture EBoV. 7h after the virus infects the cells, viral RNA can be detected in the cultures, the peak is reached at 18h, and the cellular lesions can be seen after 48h. 7-8 days later, the cells become rounded, wrinkled. Intracellular viral inclusion bodies were visible after staining.
Transmission method
A variety of non-human primates are generally susceptible to infection through the intestinal, non-gastrointestinal or intranasal routes can cause infection, 2 to 5 days after infection, high fever, 6 to 9 days after death. Blood contains the virus from 1 to 4 days after the onset of the disease until death. Guinea pigs, hamsters, and suckling mice are more sensitive and can be infected by intraperitoneal, intravenous, intradermal, or intranasal routes of inoculation. Adult mice and chicken embryos are not susceptible. The population is generally susceptible, regardless of age or sex. High-risk groups include patients with Ebola hemorrhagic fever, people in close contact with infected animals such as medical personnel, inspectors, and workers at Ebola epidemic sites.
Experts in the study found that the Ebola virus is heat-resistant but will be killed in 60 minutes at 60 degrees Celsius. The virus mainly exists in the patient's body fluids, blood, so the patient used syringes, needles, a variety of puncture needles, cannulas, etc., should be thoroughly disinfected, the most reliable is to use high-pressure steam sterilization. Ebola may also be airborne. Experimenters exposed the heads of rhesus monkeys to the outside of their cages and allowed them to inhale an aerosol containing the virus at a diameter of about 1 micron, and the monkeys developed the disease 4 to 5 days later. The sera of six staff members who were in close contact with the sick monkeys on a daily basis were found to be positive for antibodies to the virus, and five of them had not suffered trauma or had a history of injections, so it is thought that it could be transmitted by droplet. [4]
The virus can be transmitted through direct contact with the patient's body fluids, or through contact with the patient's skin or mucous membranes. The incubation period of the virus can range from 2 to 21 days, but is usually only 5 to 10 days.
While airborne transmission between monkeys has been demonstrated in the laboratory, it has not been proven that the virus can be transmitted from person to person through the air. Nurse Mainka is a possible case of airborne transmission, and researchers aren't sure how she came into contact with the virus. Much of the Ebola epidemic is due to the hospital environment, where poor public **** hygiene, needles discarded everywhere, and the lack of negative pressure rooms pose a great threat to healthcare workers. Because of better equipment and hygiene, it is almost impossible for Ebola to break out into a large epidemic in modern hospitals.
In the early stages of the disease, Ebola may not be highly contagious. Contact with a patient during this period may not even result in infection. As the disease progresses, the patient's body fluids from diarrhea, vomiting and bleeding will be highly biohazardous. Because of the lack of proper medical equipment and hygiene training, large epidemics tend to occur in impoverished areas that do not have modern hospitals and trained medical personnel. Many of the areas where the source of infection is present have exactly these characteristics. In such environments, the only measures available to control the disease are: prohibition of *** enjoyment of needles, and no reuse of needles under strict sterilization; isolation of patients; and the use of disposable masks, gloves, goggles, and protective clothing, following strict protocols in all cases. These measures should be strictly enforced by all health care workers and visitors.
The World Health Organization issued a communiqué on Oct. 6, 2014, saying that Ebola is not airborne and there is no evidence of mutation of the virus. Therefore, some claims that the Ebola virus may mutate to become airborne are unfounded speculation. WHO emphasized that studies have shown that all previous cases of Ebola have been contracted through direct contact with symptomatic patients. The Ebola virus is transmitted by direct contact with the patient's bodily fluids, of which the patient's blood, feces and vomit are the most infectious, and the virus can also be found in the patient's breast milk, urine and semen, and there is a certain risk of contagion from saliva and tears, although no intact live viruses have ever been detected in samples of the patient's sweat.
4. Main Distribution
So far, the Ebola hemorrhagic fever has Ebola hemorrhagic fever has so far been mainly endemic, confined to the Central African rainforests and the savannahs of Southeast Africa, but has expanded from Sudan and the Democratic Republic of the Congo*** and countries to the Congo*** and countries, the Central African*** and countries, Libya, Gabon, Nigeria, Kenya, C?te d'Ivoire, Cameroon, Zimbabwe, Uganda, Ethiopia, and South Africa. Occasional cases have been reported outside of Africa, all of which were imported or accidental laboratory infections, and no epidemics of Ebola hemorrhagic fever have been detected. Ebola virus is only intermittently endemic in individual countries and regions, and is somewhat limited in space and time. Epidemic area infection, off-site disease: so far, the United States, the United Kingdom, Switzerland reported imported cases, are traveling in endemic areas, involved in the diagnosis and treatment of patients or involved in the investigation of researchers. There is no epidemic.