Ebola

Ebola virus disease (EVD), formerly known as Ebola hemorrhagic fever, is a rare but severe, often fatal illness in humans. The virus is transmitted to people from wild animals and spreads in the human population through human-to-human transmission. The average EVD case fatality rate is around 50%. Case fatality rates have varied from 25% to 90% in past outbreaks¹.

EVD first appeared in 1976 in 2 simultaneous outbreaks, one in what is now Nzara, South Sudan, and the other in Yambuku, DRC. The latter occurred in a village near the Ebola River, from which the disease takes its name. A 2014–2016 outbreak in West Africa was the largest Ebola outbreak since the virus was first discovered in 1976. The outbreak started in Guinea and then moved across land borders to Sierra Leone and Liberia¹. Since 2016 sporadic outbreaks have occurred in African countries including a 2022 outbreak in Uganda².

WHAT ARE THE SYMPTOMS?

Symptoms may appear anywhere from 2 to 21 days after contact with the virus, with an average of 8 to 10 days. The course of the illness typically progresses from “dry” symptoms initially (such as fever, aches and pains, and fatigue), and then progresses to “wet” symptoms (such as diarrhea and vomiting) as the person becomes sicker.

Primary signs and symptoms of Ebola often include some or several of the following³:

• Fever
• Aches and pains, such as severe headache and muscle and joint pain
• Weakness and fatigue
• Sore throat
• Loss of appetite
• Gastrointestinal symptoms including abdominal pain, diarrhea, and vomiting
• Unexplained hemorrhaging, bleeding or bruising

Many common illnesses can have the same symptoms as EVD, including influenza (flu), malaria, or typhoid fever.
Studies show that survivors of Ebola virus infection have antibodies (proteins made by the immune system that identify and neutralize invading viruses) that can be detected in the blood up to 10 years after recovery. Survivors are thought to have some protective immunity to the type of Ebola that sickened them.

HOW IS IT TRANSMITTED?

It is understood that people are initially infected with Ebola virus through contact with an infected animal, such as a fruit bat or nonhuman primate. Following the initial infection, the virus can spread from person to person through direct contact (such as through broken skin or mucous membranes in the eyes, nose, or mouth) with⁴:

• Blood or body fluids (urine, saliva, sweat, feces, vomit, breast milk, amniotic fluid, and semen) of a person who is sick with or has died from Ebola virus disease (EVD).
• Objects (such as clothes, bedding, needles, and medical equipment) contaminated with body fluids from a person who is sick with or has died from EVD.
• Infected fruit bats or nonhuman primates (such as apes and monkeys).
• Semen from a man who recovered from EVD (through oral, vaginal, or anal sex). The virus can remain in certain body fluids (including semen) of a patient who has recovered from EVD, even if they no longer have symptoms of severe illness. There is no evidence that Ebola can be spread through sex or other contact with vaginal fluids from a woman who has had Ebola.

During an Ebola outbreak, the virus can spread quickly within healthcare settings (such as clinics or hospitals). Clinicians and other healthcare personnel providing care should use dedicated, preferably disposable, medical equipment. Proper cleaning and disposal of instruments such as needles and syringes are important. If instruments are not disposable, they must be sterilized before using again⁴.

WHO IS AT GREATEST RISK?

• Health workers who do not use proper infection control while caring for Ebola patients, and family and friends in close contact with Ebola patients, are at the highest risk of getting sick. Ebola can spread when people come into contact with infected blood or body fluids⁴.
• Ebola poses little risk to travelers or the general public who have not cared for or been in close contact (within 3 feet or 1 meter) with someone sick with Ebola⁴.

HOW IS IT CONTROLLED?

An outbreak of Ebola Virus Disease can be controlled by breaking the chain of infection. Previous Ebola outbreaks have been halted through a combination of control measures including, case management, infection prevention and control practices, surveillance and contact tracing, a good laboratory testing service, safe and dignified burials, social mobilization and effective communication¹.
Vaccines to protect against Ebola have been developed and have been used to help control the spread of Ebola outbreaks in Guinea and in the Democratic Republic of the Congo (DRC)¹.

The best defense against Ebola and other viral and bacterial diseases is prevention.

• Follow and state up-to-date on local, regional and/or national public health recommendations.
• Establish policies and training on symptoms and risk factors for employees in high-risk areas.
• Train and encourage employees to practice good personal hygiene, including washing their hands frequently with soap and water or using an alcohol-based hand rub.
• Clean and disinfect hard, non-porous surfaces and areas that are touched frequently. Use disinfectants approved for use against Ebola by the local national authority and if not available use disinfectants recommended by national public health authorities, or the World Health Organization. For example, in the US, use an EPA-registered disinfectant with a claim against Ebola or a product listed as having an emerging viral pathogen claim⁵. In the EU, use a disinfectant labeled with either ‘Virucidal’, ‘Limited Spectrum Virucidal’ or ‘Virucidal Activity against enveloped viruses’ activity⁶. Always follow the manufactures use instructions, including concentration, application and contact time.
• Make sure you have personal protective equipment (PPE), such as gloves, goggles and gowns, on hand and ensure that employees are trained in its proper use.
• Ensure that needles and sharps are disposed of in an appropriate manner.

REFERENCES AND FURTHER INFORMATION

¹ Ebola virus disease (who.int)
²Ebola outbreak 2022 - Uganda (who.int)
³Signs and Symptoms | Ebola Hemorrhagic Fever | CDC
⁴Transmission | Ebola Hemorrhagic Fever | CDC
⁵List L: Disinfectants for Use Against Ebola Virus | US EPA
⁶Explanation of virus claims for disinfectants | Biocides | Board for the Authorisation of Plant Protection Products and Biocides (ctgb.nl)