1. EBOLA VIRUS INFECTION
Ebola virus disease (EVD), also known as Ebola hemorrhagic fever (EHF) or simply Ebola, is a viral hemorrhagic fever of humans and other primates caused by ebola viruses.
The disease was first identified in 1976 in two simultaneous outbreaks, one in Nzara, and the other in Yambuku, a village near the Ebola River from which the disease takes its name
 EVD outbreaks occur intermittently in tropical regions of sub-Saharan Africa
 Between 1976 and 2013, the W H O reports a total of 24 outbreaks involving 1,716 cases. The largest outbreak to date was the epidemic in West Africa, which occurred from December 2013 to January 2016 with 28,616 cases and 11,310 deaths. It was declared no longer an emergency on 29 March 2016. Another outbreak in Africa began in May 2017 in the Democratic Republic of the Congo

2. Cause
There are five identified species (types) of Ebola virus. Four of the five have caused disease in humans:
Zaire ebolavirus
Sudan ebolavirus
Taï Forest ebolavirus
Bundibugyo ebolavirus
Reston ebolavirus (has not caused illness in humans)

3. Reservoir
The natural reservoir for Ebola has yet to be confirmed; however, bats are considered to be the most likely candidate species.
Three types of fruit bats were found to possibly carry the virus without getting sick. As of 2013, whether other animals are involved in its spread is not known.
 Traces of EBOV were detected in the carcasses of gorillas and chimpanzees during outbreaks in 2001 and 2003, which later became the source of human infections. However, the high rates of death in these species resulting from EBOV infection make it unlikely that these species represent a natural reservoir for the virus.

4. Pathophysiology
Similar to other filoviruses, EBOV replicates very efficiently in many cells, producing large amounts of virus in monocytes, macrophages, dendritic cells and other cells including liver cells, fibroblasts, and adrenal gland cells Viral replication triggers the release of high levels of inflammatory chemical signals and leads to a septic state
EBOV is thought to infect humans through contact with mucous membranes or through skin breaks.
 Once infected, endothelial cells (cells lining the inside of blood vessels), liver cells, and several types of immune cells such as macrophages, monocytes, and dendritic cells are the main targets of infection] Following infection with the virus, the immune cells carry the virus to nearby lymph nodes where further reproduction of the virus takes place. From there, the virus can enter the bloodstream and lymphatic system and spread throughout the body.
Endothelial cells may be infected within three days after exposure to the virus. The breakdown of endothelial cells leading to blood vesselinjury can be attributed to EBOV glycoproteins

5. Transmission

6. . 1.     Direct contact with an infected animal or human;
2.      Direct contact with the blood and or secretions of an infected person especially within families;
3.      Contact with contaminated medical equipment such as needles;
4.      Reuse of unsterilized needles in hospital;
5.      Eating or handling of the carcass of infected animals;
6.      Inhalation of contaminated air in hospital environment;
7.      Use of infected non human primate/bats as food source;
8.      Non implementation of universal precautions.
The Ebola virus may be able to persist for more than 3 months in the semen after recovery, which could lead to infections via sexual intercourse
Virus persistence in semen for over a year has been recorded in a national screening programme.
 Ebola may also occur in the breast milk of women after recovery, and it is not known when it is safe to breastfeed again.
Dead bodies remain infectious;

7. Signs and symptoms

8. Onset
incubation period is between 2 and 21 days, and usually between 4 and 10]
Symptoms usually begin with a sudden influenza-like stage characterized by feeling tired, fever, weakness, decreased appetite, muscular pain, joint pain, headache, and sore throat.
The fever is usually higher than 38.3 °C (101 °F).
 This is often followed by vomiting, diarrhea and abdominal pain. Next, shortness of breath and chest pain may occur, along with swelling, headaches and confusion. 
In about half of the cases, the skin may develop a maculopapular rash, , 5 to 7 days after symptoms begin.

9. Bleeding
In some cases, internal and external bleeding may occur.
This typically begins five to seven days after the first symptoms.
 All infected people show some decreased blood clotting
 Bleeding from mucous membranes or from sites of needle punctures has been reported in 40–50 percent of cases. This may cause hematemesis, hemoptysis, or bloody stool 
Bleeding into the skin may create petechiae, purpura, ecchymoses or hematomas (especially around needle injection sites). Bleeding into the whites of the eyes may also occur. Heavy bleeding is uncommon; if it occurs, it is usually located within the gastrointestinal tract.

10. Recovery and death
Recovery may begin between 7 and 14 days after first symptoms.
 Death, if it occurs, follows typically 6 to 16 days from first symptoms and is often due to low blood pressure from fluid loss.
 In general, bleeding often indicates a worse outcome, and blood loss may result in death. People are often in a coma near the end of life.
Those who survive often have ongoing muscular and joint pain, liver inflammation, decreased hearing, and may have continued tiredness, continued weakness, decreased appetite, and difficulty returning to pre-illness weight. Problems with vision may develop.
Additionally, survivors develop antibodies against Ebola that last at least 10 years, but it is unclear if they are immune to repeated infections.

11. Diagnosis Laboratory testing
Possible non-specific laboratory indicators of EVD include a low platelet count; an initially decreased white blood cell count followed by an increased white blood cell count elevated levels of the liver enzymes  (ALT) and  (AST); and abnormalities in blood clotting often consistent with  (DIC) such as a prolonged prothrombin time, partial thromboplastin time, and bleeding time.
The specific diagnosis of EVD is confirmed by isolating the virus, detecting its RNA or proteins, or detecting antibodies against the virus in a person's blood. Isolating the virus by cell culture, detecting the viral RNA by  (PCR) and detecting proteins by  (ELISA) are methods best used in the early stages of the disease and also for detecting the virus in human remains. Detecting antibodies against the virus is most reliable in the later stages of the disease and in those who recover  IgM antibodies are detectable two days after symptom onset and IgG antibodies can be detected 6 to 18 days after symptom onset. 
the most common and sensitive diagnostic methods are real-time PCR and ELISA.
 In 2015 a rapid antigen test which gives results in 15 minutes was approved for use by WHO. It is able to confirm Ebola in 92% of those affected

12. Management Treatment is primarily supportive in nature.
Early supportive care with rehydration and symptomatic treatment improves survival.
Rehydration may be via the oral or by intravenous route.These measures may include management of pain, nausea, fever and anxiety. The World Health Organization recommends avoiding the use of aspirin or ibuprofen for pain due to the bleeding risk associated with use of these medications.
Blood products such as packed red blood cells, platelets or fresh frozen plasma may also be used. Other regulators of coagulation have also been tried including heparin in an effort to prevent (DIC) and clotting factors to decrease bleeding.
Antimalarial medications and antibiotics are often used before the diagnosis is confirmed, though there is no evidence to suggest such treatment helps. A number of experimental treatments are being studied.

13. Intensive care
Intensive care is often used in the developed world.
 This may include maintaining blood volume and electrolytes (salts) balance as well as treating any bacterial infections that may develop.
 Dialysis may be needed for kidney failure, and extracorporeal membrane oxygenation may be used for lung dysfunction.

14. Prognosis
EVD has a high risk of death in those infected which varies between 25 percent and 90 percent of those infected. As of September 2014, the average risk of death among those infected is 50 percent. The highest risk of death was 90 percent in the 2002–2003 Republic of the Congooutbreak.
Death, if it occurs, follows typically six to sixteen days after symptoms appear and is often due to low blood pressure from fluid loss. Early supportive care to prevent dehydration may reduce the risk of death.
If an infected person survives, recovery may be quick and complete. Prolonged cases are often complicated by the occurrence of long-term problems, such as inflammation of the testicles, joint pains, muscular pain, skin peeling, or hair loss.
 Eye symptoms, such as light sensitivity, excess tearing, and vision loss have been described.
Ebola can stay in some body parts like the eyes, breasts, and testicles after infection.Sexual transmission after recovery has been suspected.]

15. Vaccine
Fortunately, in December 2016, researchers reported on a human clinical trial of rVSV-ZEBOV vaccine that was apparently effective and relatively safe for vaccination against Ebola disease. The researchers used people (contacts) exposed to Ebola patients during the outbreak in a trial following similar procedures ("ring of exposure") used to eliminate smallpox. The Ebola case exposure patient was randomly assigned to get the vaccine at day 0 or 21 days later after being identified as a new case exposure. Although many vaccinated people developed side effects of injection-site pain, mild headache, fatigue and muscle pain, most individuals recovered within a few days and none develop long-term problems. The study involved 11,841 people. The vaccine was 100% effective in patients who obtained the vaccine at day 0 and those day 0 individuals who had no symptoms within 10 days (due to the approximate average incubation period of Ebola).

16. Prevention

17. How is Ebola Virus Disease prevented?
1.      Avoid contact with the blood/secretions of Ebola infected animals and humans or dead bodies by:
a)      Maintain good hygiene and sanitation practices in hospitals;
b)      Isolate Ebola infected patients;
c)      Dispose of dead bodies of Ebola patients properly in a safe manner;
d)     Avoid local traditional burial rituals such as embalming for Ebola patients;
2.      Health workers and visitors caring for Ebola patients should:
a)      Wear proper personal protective equipment such as disposable face mask. Gloves, goggles,
b)      and gown always;
c)      Use disposable needles;
d)     Avoid reuse of needles or use of inadequately sterilized needles;