Ebola Virus Disease (EVD)

Symptoms, Causes, Prevention & Treatment

Ebola Virus Disease (EVD) is a severe and often fatal illness caused by the Ebola virus. Since its discovery, the virus has led to multiple Ebola outbreaks, primarily in Africa, with devastating effects on human populations and healthcare systems. Understanding what causes Ebola, its symptoms, transmission, and prevention strategies is essential for global health preparedness. This article provides an in-depth exploration of the Ebola virus disease, focusing on its history, origin, symptoms, transmission, prevention, vaccine development, and treatment options.

Key Facts About Ebola Virus Disease

• First Identified: 1976 in the Democratic Republic of the Congo and Sudan.
• Transmission: Spreads through bodily fluids like blood, saliva, vomit, and urine.
• Symptoms: High fever, severe headache, muscle pain, vomiting, diarrhea, and internal/external bleeding.
• Fatality Rate: Can range from 25% to 90%, depending on the outbreak and healthcare response.
• Treatment: No specific cure, but supportive care (IV fluids, oxygen therapy, and experimental treatments) can improve survival chances.
• Prevention: Includes vaccination (Ervebo), hand hygiene, PPE for healthcare workers, and safe burial practices.

History and Origin of the Ebola Virus

Discovery and Early Outbreaks

The Ebola virus was first identified in 1976 during two simultaneous outbreaks in Nzara, South Sudan, and Yambuku, Democratic Republic of the Congo (DRC). The disease was named after the Ebola River, near Yambuku, where one of the outbreaks occurred. These initial outbreaks resulted in high fatality rates, killing up to 90% of infected individuals.

Origin of the Ebola Virus

Scientists believe that Ebola is a zoonotic virus, meaning it originates in animals and can jump to humans. The primary natural reservoir of the virus is thought to be fruit bats (Pteropodidae family). The virus is transmitted to humans through direct contact with infected animals, such as:\n\n- Fruit bats (carriers of the virus)\n- Monkeys, gorillas, and chimpanzees\n- Antelopes and porcupines found dead in the forest

Spread and Global Awareness

Over the years, Ebola outbreaks have been reported mainly in Central and West Africa, including Uganda, Gabon, the Republic of Congo, and Sierra Leone. The most devastating outbreak occurred between 2014-2016 in West Africa, which resulted in over 28,000 cases and 11,000 deaths. This outbreak brought global attention to the need for vaccines, better healthcare infrastructure, and international response measures.

Ebola Virus Symptoms

Ebola Virus Disease (EVD) progresses in different stages, starting with mild flu-like symptoms and worsening into severe complications. Symptoms typically appear 2 to 21 days after exposure to the virus.

Early Symptoms (First 1-5 Days)

Initially, Ebola symptoms resemble common illnesses like the flu or malaria, including:

• High fever (above 101°F or 38.3°C)
• Severe headache
• Muscle and joint pain
• Sore throat
• Extreme fatigue and weakness

Progressive Symptoms (Days 5-10)

As the disease worsens, more severe symptoms appear, such as:

• Vomiting and diarrhea (sometimes bloody)
• Severe abdominal pain
• Skin rash
• Impaired kidney and liver function

Severe and Life-Threatening Symptoms (Days 10-21)

In critical cases, internal and external bleeding occurs, leading to:

• Bleeding from the nose, gums, or eyes
• Blood in vomit, stool, or urine
• Organ failure
• Shock and coma

Due to these severe effects, Ebola has a high fatality rate (25%-90%), depending on medical care availability. Immediate medical attention is crucial for increasing survival chances.

Ebola Virus Transmission

Ebola Virus Disease (EVD) spreads through direct contact with the body fluids of an infected person or contaminated surfaces. The virus does not spread through the air, like the flu or COVID-19.

How is Ebola Transmitted?

1. Human-to-human transmission

Ebola spreads through contact with:

• Blood, saliva, sweat, urine, feces, vomit, breast milk, or semen of an infected person.
• Broken skin or mucous membranes (eyes, nose, mouth) coming into contact with infected fluids.
• Contaminated objects like needles, syringes, bedding, or clothing.
• Sexual transmission, as the virus can remain in semen for months after recovery.

2. Animal-to-Human Transmission

Ebola originates from wild animals and spreads to humans through:

• Consumption or handling of infected bushmeat (monkeys, bats, antelopes).
• Direct contact with infected fruit bats, which are believed to be the natural reservoirs.
• Exposure to sick or dead primates, such as gorillas or chimpanzees.

3. Transmission in Healthcare Settings

• Healthcare workers face high risk if they do not use proper Personal Protective Equipment (PPE).
• Unsafe injection practices or improper disposal of medical waste can spread the virus.

4. Transmission During Funerals

Ebola transmission during funerals is a significant concern, as the virus remains highly contagious in the bodies of deceased individuals. Traditional burial practices, such as washing, touching, or kissing the body, increase the risk of infection. Family members, mourners, and funeral workers who come into direct contact with bodily fluids can contract the virus. To prevent transmission, safe burial practices must be followed, including handling the body with protective equipment, disinfecting burial sites, and ensuring minimal direct contact. Health authorities often train burial teams to conduct dignified yet safe funerals, reducing the risk of further spread while respecting cultural traditions.

How Ebola Does NOT Spread

Ebola does not spread through the air, water, or casual contact. Here’s how it does NOT spread:

1. Airborne Transmission – Unlike the flu or COVID-19, Ebola does not spread through the air by coughing or sneezing.
2. Water or Food – It does not spread through drinking water or most foods. However, consuming bushmeat (wild animal meat) from infected animals can be a risk.
3. Mosquitoes or Insects – Unlike malaria or dengue, Ebola is not transmitted by mosquitoes or other insects.
4. Casual Contact – Shaking hands, hugging, or being near someone without bodily fluids involved does not typically spread Ebola.
5. Recovered Individuals – Once a person recovers and is cleared by doctors, they cannot spread Ebola through casual contact, though the virus can persist in certain body fluids (like semen) for a while.

Ebola spreads only through direct contact with an infected person’s bodily fluids (blood, saliva, sweat, vomit, feces, urine, breast milk, or semen) or contaminated surfaces.

Ebola Prevention and Control

Since Ebola Virus Disease (EVD) has a high fatality rate, preventing infection and controlling outbreaks is crucial. Strategies include hygiene practices, vaccination, early detection, and safe handling of infected individuals.

1. Preventive Measures

A. Personal Hygiene and Protection

• Frequent handwashing with soap and water or alcohol-based sanitizers.
• Avoid contact with infected individuals and their bodily fluids.
• Use gloves and protective gear (PPE) when caring for patients.
• Avoid touching your eyes, nose, and mouth with unwashed hands.

B. Safe Burial Practices

• Do not touch or wash the body of an Ebola victim.
• Only trained health workers should handle burials using proper safety gear.

C. Avoiding Animal-to-Human Transmission

• Avoid handling or eating bushmeat (monkeys, bats, antelopes).
• Do not touch sick or dead animals in Ebola-affected areas.

2. Controlling Ebola Outbreaks

A. Rapid Detection and Isolation

• Early diagnosis and isolation of infected patients prevent further spread.
• Healthcare workers must follow strict infection control protocols.

B. Quarantine and Contact Tracing

• Monitor and isolate anyone who had close contact with an infected person.
• Quarantine suspected cases for 21 days, the Ebola incubation period.

C. Vaccination

• The Ervebo vaccine (rVSV-ZEBOV) protects against Ebola.
• Given to healthcare workers and at-risk individuals in outbreak areas.

3. Healthcare and Public Awareness

Ebola prevention relies heavily on healthcare measures and public awareness. Early detection and isolation of infected individuals are crucial to stopping the spread. Healthcare workers must use protective equipment such as gloves, masks, gowns, and goggles to ensure safety. Proper hygiene, including frequent handwashing with soap or hand sanitizers, plays a significant role in prevention. Safe burial practices for Ebola victims are essential, as the virus can still spread from the deceased. Public awareness campaigns help educate communities about symptoms, transmission, and the importance of seeking medical help immediately. Avoiding direct contact with infected individuals, their bodily fluids, or contaminated objects is necessary. Misinformation must be countered with reliable health information to ensure people follow proper guidelines. Effective healthcare systems, combined with widespread awareness, can significantly reduce the risk of Ebola outbreaks.

4. Travel Restrictions in Affected Areas

• Screening travelers from Ebola-affected regions.
• Avoiding non-essential travel to outbreak zones.

Preventing and controlling Ebola requires strict hygiene, early detection, vaccinations, and public awareness. Governments and health organizations must work together to stop the spread and protect communities.

Ebola Vaccine Development

Ebola Virus Disease (EVD) has a high fatality rate, making the development of an effective vaccine crucial for prevention. Over the years, researchers have worked on vaccines to protect high-risk individuals, particularly healthcare workers and people in outbreak regions.

1. Early Efforts in Ebola Vaccine Research

• Scientists began developing experimental Ebola vaccines after the 1976 outbreak in the Democratic Republic of the Congo (DRC).
• However, due to sporadic outbreaks and limited funding, vaccine development was slow.
• The 2014–2016 West Africa outbreak led to increased global efforts to create a licensed Ebola vaccine.

2. Ervebo (rVSV-ZEBOV): The First Approved Ebola Vaccine

• Approved in 2019 by the U.S. FDA and WHO.
• Developed by Merck & Co., Inc.
• Uses a weakened vesicular stomatitis virus (VSV) to carry the Ebola virus protein, stimulating an immune response.
• Provides high protection against the Zaire Ebola virus strain.
• Given as a single-dose injection and used in ring vaccination strategies to contain outbreaks.

3. Other Ebola Vaccines Under Development

Several Ebola vaccines are currently under development to improve protection against the virus. Researchers are working on vaccines targeting different strains of the Ebola virus, such as Sudan and Bundibugyo, in addition to the Zaire strain. Some promising candidates include the rVSV-based vaccines, which use a genetically modified virus to stimulate an immune response, and adenovirus vector vaccines, which use weakened viruses to deliver Ebola proteins. Scientists are also exploring multivalent vaccines that protect against multiple strains in a single dose. Clinical trials are ongoing to ensure their safety and effectiveness, with global health organizations supporting these efforts to prevent future outbreaks.

A. Zabdeno (Ad26.ZEBOV) and Mvabea (MVA-BN-Filo)

• Developed by Johnson & Johnson.
• Requires two doses given eight weeks apart.
• Provides long-term immunity but is not used for emergency outbreak response.

B. GamEvac-Combi

• Developed by Russia’s Gamaleya Institute.
• Uses a prime-boost strategy for extended immunity.

C. Emerging Multi-Strain Vaccines 

Emerging multi-strain vaccines are being developed to provide broader protection against various strains of the Ebola virus, including Zaire, Sudan, and Bundibugyo. Traditional vaccines primarily target a single strain, but multi-strain vaccines aim to protect against multiple variants in a single dose. Researchers are using advanced technologies such as viral vector platforms and mRNA-based approaches to enhance immune response and long-term immunity. These vaccines are currently undergoing clinical trials to assess their safety and effectiveness. If successful, they could play a crucial role in preventing future outbreaks and improving global preparedness against Ebola.

4. Impact of Ebola Vaccination

• Drastically reduced outbreaks in affected regions.
• Protected frontline healthcare workers and people in high-risk areas.
• Used in ring vaccination campaigns to prevent further transmission.

5. Challenges in Ebola Vaccine Distribution

• Cold storage requirements make distribution difficult in rural areas.
• Limited production capacity affects availability during outbreaks.
• Vaccine hesitancy and misinformation slow down immunization efforts.

Ebola vaccine development has made significant progress, with Ervebo being the first widely used vaccine. Ongoing research aims to create more effective, multi-strain vaccines to prevent future outbreaks.

Ebola Outbreaks and Global Impact

Ebola is a highly contagious and deadly virus that has caused outbreaks primarily in sub-Saharan Africa. The disease is transmitted through direct contact with bodily fluids from an infected person or animal. Symptoms include fever, vomiting, diarrhea, muscle pain, and in severe cases, hemorrhagic fever, which can lead to organ failure and death.

Major Ebola Outbreaks:

1. 1976 Outbreak (Zaire and Sudan): The first recognized Ebola outbreaks occurred in Sudan and Zaire (now the Democratic Republic of Congo). The virus was named after the Ebola River in Congo.

2. 2014-2016 West Africa Outbreak: This was the largest outbreak in history, affecting Guinea, Liberia, and Sierra Leone, with more than 28,000 cases and over 11,000 deaths. It also spread to other countries, including the U.S. and Spain, leading to a global health crisis.

3. 2018-2020 Democratic Republic of Congo Outbreak: Another large-scale outbreak occurred in the DRC, resulting in nearly 3,500 cases and over 2,200 deaths.

Global Impact:

• Health Systems: The outbreaks strained health systems, particularly in low-resource settings, as hospitals were overwhelmed, and healthcare workers were at high risk of infection. This led to challenges in providing care for both Ebola patients and other medical needs.

• Economic Consequences: The outbreaks disrupted economies in affected regions, with industries such as agriculture, trade, and tourism suffering due to the fear of spread and travel restrictions.

• International Response: Global organizations, including the World Health Organization (WHO) and Médecins Sans Frontières (MSF), responded with aid and medical assistance. Research into vaccines, such as the rVSV-ZEBOV vaccine, has made significant progress, and there has been a stronger focus on global preparedness.

• Psychosocial Effects: The fear of Ebola, combined with quarantines and loss of life, caused significant psychological stress in affected communities. There was also a cultural impact, as traditional funeral practices, which involved close contact with the deceased, were linked to the spread of the virus.

Ebola Treatment and Cure

Ebola is a severe and often fatal illness, but advances in treatment and prevention have improved over the years. While there is no definitive cure for Ebola, significant progress has been made in treating those infected and managing outbreaks.

Treatment for Ebola:

1. Supportive Care:

   • Hydration: One of the main treatment methods is providing intravenous fluids (IV) to keep the body hydrated. Electrolyte imbalances and dehydration are common in Ebola patients due to vomiting and diarrhea.
   • Oxygen Therapy: Patients may need oxygen if their blood oxygen levels are low.
   • Pain and Symptom Management: Medications to control pain, reduce fever, and manage other symptoms such as nausea, vomiting, and diarrhea are often given.

2. Antiviral Medications: Several experimental antiviral treatments have been tested, with some showing promising results:

   • Remdesivir: This antiviral drug, originally developed for treating other viruses like COVID-19, has shown some effectiveness in treating Ebola.
   • Favipiravir: Another antiviral that has been tested for its potential in treating Ebola.
   • ZMapp: This is a combination of monoclonal antibodies that showed effectiveness during the 2014 outbreak. It has since been used in treating infected individuals under emergency conditions.

3. Monoclonal Antibodies:

   • Inmazeb (REGN-EB3): This is a combination of three monoclonal antibodies that target the Ebola virus. It was approved by the FDA in 2020 and has been used with great success, significantly improving survival rates in clinical trials.
   • Ebanga (mAb114): Another monoclonal antibody treatment that has shown effectiveness in clinical trials. It was approved by the FDA in December 2020.

4. Convalescent Plasma: During some outbreaks, survivors who have recovered from Ebola have donated blood plasma containing antibodies against the virus. This treatment method has been used in emergencies, though its effectiveness is still being studied.

5. Vaccine: While not a treatment for those already infected, the rVSV-ZEBOV vaccine is the first licensed vaccine for Ebola and is highly effective in preventing infection, especially during outbreaks. Vaccination campaigns targeting at-risk populations have been instrumental in controlling Ebola outbreaks and preventing further spread.

Cure and Long-Term Outcomes:

While the above treatments can significantly improve survival rates, particularly with early intervention, there is still no definitive cure for Ebola. The survival rate can vary greatly depending on the strain of the virus, how early the infection is detected, and the effectiveness of the supportive care provided. Some patients who survive Ebola may experience post-Ebola syndrome, which includes joint pain, fatigue, vision problems, and neurological issues. This highlights the long-term effects of the virus on the body.

Ongoing Research:

Ongoing research continues to focus on finding more effective treatments and a complete cure for Ebola. Efforts are also being directed at better understanding the virus and improving rapid diagnostic tools, vaccines, and therapies for future outbreaks.

Ebola virus disease remains one of the world’s most dangerous viral infections, requiring global vigilance, medical advancements, and public health interventions. With continuous research on Ebola prevention, vaccines, and treatment, the world is better prepared to manage future outbreaks. By understanding what causes Ebola, recognizing Ebola virus symptoms, and following strict Ebola prevention and control measures, we can minimize its devastating effects on communities worldwide.