EXPLAINER: All you need to know about Ebola

EXPLAINER: All you need to know about Ebola
Strand of Ebola Virus

Health authorities in Uganda on Tuesday declared outbreak of Ebola after they confirmed a case of the relatively rare Sudan strain.

The health ministry and World Health Organization (WHO) said that a 24-year-old man in Uganda’s central Mubende district showed symptoms and later died.

“We want to inform the country that we have an outbreak of Ebola which we confirmed yesterday (Monday),” said Diana Atwine, the Uganda health ministry’s permanent secretary at a news conference.

The news sent a fever not just for people who work and live within the borders of Uganda, but also for the neighboring countries and beyond, given how fast people can move from one corner of the earth to the other.

What is Ebola Virus Disease?

WHO defines Ebola Virus Disease (EVD) as a deadly disease with occasional outbreaks that occur mostly on the African continent. EVD most commonly affect people and nonhuman primates (such as monkeys, gorillas, and chimpanzees). It is caused by an infection with a group of viruses within the genus Ebolavirus:

The strains include Ebola virus (species Zaire ebolavirus), Sudan virus (species Sudan ebolavirus), Taï Forest virus (species Taï Forest ebolavirus, formerly Côte d’Ivoire ebolavirus), Bundibugyo virus (species Bundibugyo ebolavirus), Reston virus (species Reston ebolavirus) and Bombali virus (species Bombali ebolavirus)

“Of these, only four (Ebola, Sudan, Taï Forest, and Bundibugyo viruses) have caused disease in people. Beston virus can cause disease in nonhuman primates and pigs, but there have not been cases in people.

Bombali virus was first identified in bats in 2018, and experts do not know yet if it causes disease in either animals or people,” reads one of the advisories from WHO website.

Ebola virus was first discovered in 1976 near the Ebola River in what is now the Democratic Republic of Congo. Since then, the virus has been infecting people from time to time, leading to outbreaks in several African countries. Scientists do not know where Ebola virus comes from.

Based on similar viruses, they believe EVD is animal-borne, with bats or nonhuman primates being the most likely source. Infected animals carrying the virus can transmit it to other animals, like apes, monkeys, duikers and humans.

“The virus first spreads to people through direct contact with the blood, body fluids and tissues of animals. Ebola virus then spreads to other people through direct contact with body fluids of a person who is sick with or has died from EVD.

“This can occur when a person touches these infected body fluids or objects that are contaminated with them. The virus then gets into the body through broken skin or mucous membranes in the eyes, nose, or mouth.

“People can get the virus through sexual contact with someone who is sick with or has recovered from EVD. The virus can persist in certain body fluids, like semen, after recovery from the illness,” says WHO.

In the wake of the 2014 West African outbreak and 2018 Democratic Republic of the Congo outbreak, the two largest outbreaks of Ebola virus disease (EVD) to date, there are now more EVD survivors than ever before. This large number of survivors provides a chance to better understand how Ebola virus affects people who have recovered, and to advise survivors on how to take care of themselves and their communities.

Recovery from EVD depends on good supportive care and the patient’s immune response. Investigational treatments are also increasing overall survival.

Those who do recover develop antibodies that can last 10 years, possibly longer. Survivors are thought to have some protective immunity to the type of Ebola that sickened them. It is not known if people who recover are immune for life or if they can later become infected with a different species of Ebola virus. Some survivors may have long-term complications, such as joint and vision problems.

According to WHO, a large outbreak of haemorrhagic fever (subsequently named Ebola haemorrhagic fever) occurred in southern Sudan (present day South Sudan) between June and November 1976.

There was a total of 284 cases; 67 in the source town of Nzara, 213 in Maridi, 3 in Tembura, and 1 in Juba. The outbreak in Nzara appeared to have originated in the workers of a cotton factory. The disease in Maridi was amplified by transmission in a large, active hospital.

Transmission of the disease required close contact with an acute case and was usually associated with the act of nursing a patient. The incubation period was between 7 and 14 days. Although the link was not well established, it appears that Nzara could have been the source of infection for a similar outbreak in the Bumba Zone of Zaire.

In this outbreak Ebola haemorrhagic fever was a unique clinical disease with a high mortality rate (53% overall) and a prolonged recovery period in those who survived. Beginning with an influenza-like syndrome, including fever, headache, and joint and muscle pains, the disease soon caused diarrhoea (81%), vomiting (59%), chest pain (83%), pain and dryness of the throat (63%), and rash (52%).

Haemorrhagic manifestations were common (71%), being present in half of the recovered cases and in almost all the fatal cases.

Additional reporting by WHO.