Ebola virus disease or EVD is also known as Ebola haemorrhagic fever or EHF. As the name suggests this disease occur following infection by Ebola virus. Usually the first symptoms arise within 2 days to 3 weeks after initial contact with the virus. The most common presenting symptoms include high fever, sore throat, severe degree of headache, nausea, vomiting, loose motion etc. In many affected person there is impairment of normal kidney and liver functions and in some severe degree of bleeding may occur.
Several animals act as the natural reservoir of Ebola virus; these include African monkeys, chimp or primates (nonhuman), fruit bats, etc; among all the animals mentioned fruit bats are capable of harboring the virus inside their bodies without being infected by it. The usual route of contraction of infection is through contact with blood and other body fluids of an already infected animal. However, once the disease starts spreading in humans, the infection may spread by infected humans. Once infected, males even after being cured of the symptoms may spread the disease through sexual contact (via seminal fluid) for about 2 months.
There is no specific treatment for Ebola virus. Symptomatic management is the cornerstone of treatment. The disease has quite high mortality rate killing about 50 to 90% of the infected persons. The disease usually occurs in the Sub Saharan countries of Africa. Currently ongoing the 2014 West Africa Ebola outbreak is considered as one of the largest outbreaks of Ebola virus disease.
Prevention of infection can be done by regular screening of susceptible animals for infections and killing and properly disposing of the infected animals are to be done, if any.
Symptoms
Usually Ebola virus disease starts with common flu like symptoms which include high grade fever, generalized body ache, tiredness, muscle and joint pain, loss of appetite. Often diarrhea and vomiting also occur. Sometimes difficulty in breathing, sore throat, resulting into difficulty in swallowing, skin rashes (in about 50% of the cases) may also occur.
In some patients a severe form of Ebola virus disease may occur. In this form bleeding occurs beneath the skin (subcutaneous area) or in the internal organs characterized by hemorrhage in the conjunctivae of the eyes, several skin manifestations as purpuric, petechial spots, ecchymoses and even hematoma (in order of severity of bleeding). Sometimes a severe degree of internal bleeding may also occur, leading to blood vomiting (due to bleeding in the upper part of the digestive tract), passage of bloody stool (due to bleeding in the lower part of the digestive tract), nose bleeding (epistaxis), gum bleeding, etc.
Bleeding usually means poor outcome and as such severe degree of blood itself may lead to death of the person. In severe cases multiple organ failure, jaundice, coma, attack of seizure and ultimately death occurs.
Some people may survive the infection although, recovery is slow and may also have some residual complications like loss of hair, loss of body weight, inflammatory changes in the liver (hepatitis), eyes and testicles (orchitis), persistent weakness, loss of appetite, etc.
Causes
Ebola virus disease is caused by four viruses, including the Ebola virus; the other three viruses are Bundibugyo virus, Sudan virus and Tai forest virus.
Ebola virus disease occurs initially through human contact with infected animal’s body fluid later human to human transmission may also occur through body fluids during sexual contact or during handling of the patient or dead body of an infected person or during the embalming procedure. Medical workers may contract infection through contact with contaminated medical and surgical instruments, needles, syringes, etc.
Bats are considered as the one of the important natural reservoir of the viruses. Half eaten fruits and their pulps by the bats may be eaten by other animals resulting into an outbreak of Ebola virus diseases in animal population which eventually may spread to humans.
The virus mainly acts by incapacitating the natural immune system of the body so that the natural protective response of the body towards this virus infection is absent.
Risk factors
Usually contracting Ebola virus infection for a normal healthy person is low however the risk increases in certain circumstances namely,
1. Travelling to endemic area mainly Africa
2. Participating in animal research without proper precautionary measures
3. Family members of an infected person
4. People who are involved in preparation of dead bodies for burial
Treatment
There is no specific cure for Ebola virus disease, supportive treatment is the mainstay of managing these patients.
These measures include avoiding dehydration by replacing lost fluid either through oral administration of ORS or intravenous fluids, giving oxygen, blood transfusion to replace the lost blood, management of secondary bacterial infection, if any.