Ebola Virus Disease: Symptoms, Transmission, Prevention, and Treatment

Comprehensive guide to Ebola virus disease: understand its symptoms, causes, risks, prevention strategies, and current treatments.

By Medha deb

Created on Oct 3, 2025

Comprehensive guide to Ebola virus disease: understand its symptoms, causes, risks, prevention strategies, and current treatments.

Ebola virus disease (EVD), also known as Ebola hemorrhagic fever, is a rare but severe and often fatal illness in humans and non-human primates. Caused by infection with one of several Ebola virus species, EVD has resulted in deadly outbreaks, particularly in sub-Saharan Africa. A deep understanding of its clinical features, causes, prevention strategies, and treatment options is essential for public health and individual protection.

What is Ebola?

Ebola virus disease is a severe, acute viral illness caused by infection with viruses of the genus Ebolavirus, which belong to the Filoviridae family. The disease was first identified in 1976 near the Ebola River in what is now the Democratic Republic of Congo. Since then, sporadic outbreaks have occurred throughout Africa, with the most significant impacting West Africa in 2014-2016.

Ebola Virus Species That Infect Humans

Zaire ebolavirus: Most common and responsible for the majority of outbreaks.
Sudan ebolavirus
Bundibugyo ebolavirus
Taï Forest ebolavirus (formerly Côte d’Ivoire ebolavirus)

Reston ebolavirus infects primates but has not caused illness in humans, while Bombali ebolavirus has been detected in bats but has not been associated with human disease.

Causes and Transmission

EVD is zoonotic, meaning it is transmitted from animals to humans and then can spread between people. Most outbreaks begin when a person comes into contact with the bodily fluids of an infected animal, such as a fruit bat or non-human primate (monkey, chimpanzee, or gorilla). Once the virus enters the human population, it spreads via direct contact.

How Ebola is Transmitted

Direct contact with blood, saliva, urine, feces, vomit, breast milk, sweat, semen, or other body fluids of an infected person.
Contact with objects contaminated by infected bodily fluids, including needles and medical equipment.
Handling or eating the meat of infected wild animals (bushmeat).
Sexual transmission can occur for months after infection, as the virus may persist in semen.

The Ebola virus is not spread through the air, water, or, in general, food sources common in non-outbreak areas. However, consumption of bushmeat from infected animals remains a risk in endemic regions.

Pathogenesis: How Ebola Affects the Body

Once inside the body, the Ebola virus attacks the immune system, impairing both innate and adaptive responses. This leads to a massive inflammatory reaction, coagulopathy (disrupted blood clotting), and damage to multiple organs.

Key effects of the virus include:

Disruption of dendritic cells and activated macrophages.
Triggering of disseminated intravascular coagulation (DIC), leading to both clotting and bleeding.
Extremely high viral loads in fatal cases; survivors typically present with lower viral counts and robust immune responses.

Symptoms of Ebola Virus Disease

Symptoms normally appear between 2 and 21 days after exposure (average 8-10 days). The clinical presentation of EVD progresses through several phases:

Initial (Non-Specific) Symptoms

Fever
Severe headache
Muscle pain
Joint pain
Chills
Weakness

Progressive Symptoms

Nausea and vomiting
Diarrhea (sometimes severe and bloody)
Abdominal pain
Chest pain and cough
Pharyngitis (sore throat)
Photophobia (sensitivity to light)
Conjunctivitis (red eyes)

Severe and Late-Stage Symptoms

Skin rash (erythema progressing to maculopapular rash, typically on days 5-7)
Desquamation (peeling) of skin
Hemorrhagic manifestations (unexplained bruising, petechiae, mucosal bleeding)
Multi-organ failure resembling septic shock
Jaundice
Pancreatitis

Key Points About Ebola Symptoms

Symptoms are not unique to Ebola and may mimic other infections, making early diagnosis challenging.
A cluster of unexplained deaths or severe illness in an area should raise suspicion, particularly if there is a risk of exposure to bodily fluids from a known case or wild animals.

Who is Most at Risk?

Individuals at the highest risk of contracting Ebola include:

Healthcare workers in close contact with Ebola patients without adequate protective equipment
Family and household members of infected individuals
Laboratory personnel handling specimens
People participating in funeral rituals involving contact with the deceased
Hunters and those preparing bushmeat in affected regions

Diagnosis of Ebola Virus Disease

Early diagnosis is difficult due to non-specific symptoms. Laboratories use the following methods to confirm infection:

RT-PCR (Reverse transcriptase-polymerase chain reaction): The main method for early detection; requires specialized laboratory capacity.
Antigen detection: FDA-approved rapid tests (such as OraQuick® Ebola Rapid Antigen Test) are now available for clinical and post-mortem use.
Serologic testing: Used primarily in research or retrospective settings.

Other laboratory findings in EVD often include:

Leukopenia, evolving to neutrophilia
Atypical lymphocytes
Elevated liver enzymes (aminotransferases)
Thrombocytopenia (low platelets)
Coagulopathy (disseminated intravascular coagulation)

Note: A negative RT-PCR test early in the course of illness does not exclude Ebola; repeat testing over 72 hours is recommended if clinical suspicion remains.

Treatment of Ebola Virus Disease

There is no specific cure for Ebola virus disease. Treatment focuses on supportive care to help the body fight off the virus and manage complications.

Supportive Care Includes:

Maintaining hydration and electrolyte balance (oral or intravenous fluids)
Monitoring blood pressure, oxygen status, and organ function
Treating secondary infections
Managing pain, nausea, and fever
Replacing lost blood components in case of severe bleeding

Mortality rates for EVD have varied between 25% and 90%, depending on the outbreak, healthcare infrastructure, and timely initiation of treatment. With proper supportive care, the chance of survival increases significantly.

Experimental Treatments

Monoclonal antibody therapies have been developed and used during outbreaks. Some, such as REGN-EB3 and mAb114, have shown promise in improving survival rates during clinical trials and compassionate use scenarios.
Experimental antiviral drugs have also been tested; ongoing research aims to develop more effective therapeutic options.

Post-Recovery Considerations

Survivors may harbor the virus in immune-privileged sites (e.g., eye, semen) for months or even years after recovery.
Vigilance and counseling are required to prevent late transmission, particularly through sexual contact.

Prevention of Ebola Virus Disease

Preventing the spread of Ebola virus disease requires coordinated public health measures, community education, and individual precautions:

Key Prevention Strategies

Strict infection control practices for healthcare workers, including the use of appropriate personal protective equipment (PPE).
Safe handling and burial of deceased individuals with suspected or confirmed EVD.
Avoiding contact with bats or non-human primates, particularly in outbreak regions.
Proper cooking and handling of meat from wild animals.
Immediate isolation of suspected cases and contact tracing.
Community engagement and education to dispel myths and reduce stigma.

Vaccines

As of recent years, vaccines to prevent Ebola infection have been developed and deployed:

rVSV-ZEBOV (Ervebo): A single-dose vaccine approved for use in several countries, effective against the Zaire ebolavirus species. It has been used in mass vaccination campaigns during outbreaks.
Additional vaccine candidates are under evaluation for other Ebola virus species.

Outbreaks and Global Impact

The largest recorded Ebola outbreak occurred in West Africa (2014-2016), resulting in more than 28,000 cases and over 11,000 deaths across Guinea, Liberia, and Sierra Leone. Smaller outbreaks have continued to occur, notably in the Democratic Republic of Congo. Each outbreak challenges public health systems and underlines the importance of preparedness, rapid response, and international cooperation.

Year	Region	Cases	Fatalities	Notable Aspects
1976	Zaire (now DRC), Sudan	~600	431	First recognized outbreaks
2000	Uganda	425	224	First major outbreak after 1970s
2014–2016	West Africa	~28,000	~11,000	Largest outbreak; international crisis
2018–2020	DRC	3,481	2,299	Use of new vaccines and therapies

Preparedness and Response

Hospitals in regions at risk of Ebola have established protocols for safe isolation, transportation, and management of suspected and confirmed patients. Teams are drilled in donning and doffing PPE, containment, and rapid mobilization of response units. Lessons from past outbreaks have improved community engagement, case detection, and international aid mobilization.

Johns Hopkins’ Role in Ebola Research and Care

Johns Hopkins Medicine and its affiliates have played a significant role in the understanding and management of Ebola virus disease by:

Conducting research into vaccine development and testing new therapeutic strategies.
Developing protocols for rapid response, including patient transport drills and protective equipment innovation.
Providing training and expertise for healthcare professionals in outbreak regions.
Participating in multi-institutional studies to track and analyze outbreaks.

Frequently Asked Questions (FAQs)

What is the natural host or reservoir for Ebola?

The most widely accepted theory identifies African fruit bats as the natural hosts of Ebola virus, although precise reservoirs remain under investigation. Outbreaks often begin following human contact with infected animals such as bats or primates.

How long does Ebola virus survive outside the body?

The Ebola virus can survive on dry surfaces for several hours and in body fluids for several days at room temperature, but it is readily killed by disinfectants like bleach and by heat.

Is there an Ebola vaccine for the general public?

The rVSV-ZEBOV (Ervebo) vaccine is approved for use in people at high risk during outbreaks, primarily in Africa. It is not routinely given to the general public, but is deployed rapidly in ring vaccination campaigns following the identification of cases.

What is the survival rate for Ebola virus disease?

Survival rates vary by outbreak and the availability of medical care. Overall mortality has ranged from 25% to 90%. Early supportive care increases the chance of survival.

Can Ebola survivors be infectious after recovery?

Yes, especially through certain body fluids such as semen, where the virus can persist for months to years. Survivors are monitored and counseled on measures to prevent possible late transmission.

Is it safe to travel to areas affected by Ebola?

Travel advisories are issued by the CDC and WHO during outbreaks. Avoiding exposure and following all public health recommendations is essential during active transmission.

What should I do if I suspect Ebola in myself or others?

If you or someone you know develops symptoms of Ebola within 21 days of possible exposure, seek medical care immediately. Inform healthcare providers of the exposure risk in advance to ensure safe isolation and testing protocols are followed.

Key Facts About Ebola: At a Glance

Ebola is a severe, often fatal illness caused by the Ebolavirus genus.
Transmission occurs through direct contact with bodily fluids or contaminated surfaces.
Symptoms can be non-specific early, but rapid progression to severe illness is common.
Treatment is primarily supportive; vaccination is available for certain outbreaks.
Strict public health measures are essential to control and prevent outbreaks.

For the latest updates on Ebola virus outbreaks, prevention guidelines, travel advisories, and research advances, always consult reputable health organizations such as the World Health Organization (WHO) and Centers for Disease Control and Prevention (CDC).

References

Author

medha deb

Medha Deb is an editor with a master's degree in Applied Linguistics from the University of Hyderabad. She believes that her qualification has helped her develop a deep understanding of language and its application in various contexts.

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