Ebola Virus Disease: Introduction, Key Facts, Mode of Transmission, Sign and Symptoms, Prevention and Control

Table of Contents

Introduction

Ebola virus disease, formerly known as Ebola hemorrhagic fever, is severe and fatal illness caused by Ebola virus that affects human and non-human primates such as chimpanzee, monkeys, gorillas.
Ebola is a virus that creates problem with how our blood clots.
The virus spreads in the body and damage the immune system and organs ultimately the blood clotting cells levels drops leading to uncontrollable bleeding.
Ebola virus disease is also known as Ebola hemorrhagic fever because the clotting problems lead to internal bleeding, as blood leaks from small blood vessels in the body.
Ebola virus first appeared in 1976 at Nzara, Sudan and at Yambuku in the democratic republic of Congo near the Ebola River in Africa from where it got its name.
Ebola virus occurs occasionally but is a deadly virus.
It is caused by an infection with a group of viruses within the genus
Ebola Virus Disease mainly strikes in the central and west Africa but also has been seen in African cities

The 2014-2016 Ebola outbreak is considered as the deadliest Ebola epidemic killing about 11,325 deaths and 28,600 infections
The case fatality of Ebola virus disease was about 50% but it varied from 25% to 90% in the past outbreaks.
Ebola is not transmitted through vector but from the wild animals.
The earlier symptoms of Ebola can mimic other illness and thus makes the early diagnosis difficult.
Ebola is a severe fatal illness and bleeding is common in later stage of the disease.
For successful control of outbreak, community engagement is one of the prime factors.
Vaccines are developed in order to prevent the disease and are found to be effective too.
Early support and care can increase the rate of survival. Care and support must be especially provided to pregnant and breastfeeding women

In Africa, fruit bats are considered to be the natural host of Ebola virus
It spreads in human through contact with the skin or bodily fluids (blood, saliva, sweat, tears, mucus, vomit, feces, breast milk, urine, and semen) of an infected person, chimpanzee, fruit bat or monkey.
Human to human transmission takes place via contact with fluids and secretions. Therefore, Ebola virus can also transmit to those who take care of the sick person or bury the dead person who suffered the disease.
The virus also spreads by touching things that have been contaminated with these fluids.
Pregnant women who suffered from acute Ebola and recovered may still carry the virus in the breast milk or pregnancy related fluids.
Semen of a man recovered from EVD can also have remains of virus but there is no evidence that supports EVD can be transmitted from the vaginal fluids of recovered women.

Symptoms of EVD include:

This is followed by:

Nausea and vomiting
Diarrhea (may be bloody)
Rashes
Red eyes
Chest pain
Stomach pain
Symptoms of impaired kidney and liver function
Severe weight loss
Bleeding, usually from the eyes, and when close to death, possible bleeding from the ears, nose and rectum
Internal bleeding
In some cases, both internal and external bleeding (for example, oozing from the gums, or blood in the stools).
Laboratory findings include low white blood cell and platelet counts and elevated liver enzymes.

Symptoms of other infectious disease such as malaria, typhoid fever clash with EVD. Thus it is sometimes difficult to differentiate between these diseases.
Even the symptoms of pregnancy are similar in EVD
Following diagnostic methods can be used to detect EVD:
antibody-capture enzyme-linked immune sorbent assay (ELISA)
antigen-capture detection tests
serum neutralization test
reverse transcriptase polymerase chain reaction (RT-PCR) assay
electron microscopy
virus isolation by cell culture

Automated or semi-automated nucleic acid tests (NAT) for routine diagnostic management.
Rapid antigen detection tests for use in remote settings where NATs are not readily available.

Integrated package of interventions such as case management, surveillance and contact tracing, a good laboratory service, safe burials and social mobilization are required for effective management of Ebola outbreak.
Raising awareness about the risk factors and protective measure including vaccine of the disease and community engagement.
Avoiding the contact with the bodily fluids such as blood, saliva, vomit of the infected person.
Avoiding contacts with the wild animals and handling the meat of wild animals.
Knowing the symptoms of Ebola virus especially in the endemic areas and consulting health care professional after it develops.
Controlling the infection in the health care setting through following the standard precautions measures while caring infected person.
Avoid funeral or burial practices that involve touching the body of someone who died from EVD or suspect EVD
It is not necessary that a recovered person from Ebola may not carry the virus. Thus, care even after recovery is essential, especially for pregnant and vulnerable ones

Food and Drug Administration (FDA) has approved ERVEBO^®vaccine as the first approved vaccine of Ebola in 2019.
ERVEBO vaccine has been found to be safe and protective against only the Zaire ebolavirusspecies of ebolavirus.
Ebola vaccine is given in a single dose to individuals above 18 years of age except for pregnant and breastfeeding women.
It is said to prevent Ebola virus disease caused by the Zaire ebolavirus.
In May 2020, a two-dose vaccine regimen was also designed to protect against Zaire ebolavirus given in the gap of 8 weeks after the first dose. Zabdeno is administered first and Mvabea is given in second dose.

Currently there are two treatment regimens to treat Ebola Virus Disease (EVD) caused by Zaire species in adult and children: Inmazeb and Ebanga
Other treatment process is to provide supportive care which includes:
Rehydration with oral or intravenous fluids
Treatment of specific symptoms and other infections if they occur
Using medication to support blood pressure, reduce vomiting and diarrhea, and to manage fever and pain.