Ebola: Symptoms, Types, Causes and Treatment

Ebola virus disease (EVD) is one of the most feared infectious diseases, notorious for its rapid onset, severe symptoms, and high fatality rates. Since its discovery, Ebola has periodically emerged to cause devastating outbreaks, most notably in West and Central Africa. Yet, despite its notoriety, Ebola remains poorly understood by many. This article sheds light on the disease, explaining its symptoms, the different types of Ebola virus, how it spreads, and the latest treatment advances—drawing on the latest scientific research.

Symptoms of Ebola

When Ebola strikes, it often does so suddenly and with a range of symptoms that can be both severe and bewildering. Understanding these symptoms is vital for early detection and care, which can improve survival rates.

Onset	Main Symptoms	Late/Severe Manifestations	Source
Sudden	Fever, Fatigue, Headache, Muscle Pain, Diarrhea, Vomiting	Hemorrhage, Multi-organ failure, Shock, Neurologic & Ocular Issues	1,2,3,4,10,11,12

Table 1: Key Symptoms

Early Symptoms: Sudden and Non-Specific

Ebola’s early symptoms often mimic other illnesses like malaria or flu, making early diagnosis challenging. Most patients present with:

• Fever: Often the first sign, with temperatures averaging around 38.6°C (101.5°F) 1.
• Fatigue and Malaise: Profound tiredness and weakness are common 1,2.
• Headache and Muscle Aches: Severe headaches, myalgia (muscle pain), and joint pain (arthralgia) are frequent 1,2,4.
• Gastrointestinal Symptoms: These include diarrhea, vomiting, and abdominal pain, which are especially prominent and can lead to dehydration 1,2,5.

Severe and Late-Stage Manifestations

As the disease progresses, more severe symptoms arise:

• Hemorrhagic Signs: Bleeding (internal and external) occurs in less than half of cases, despite the term "hemorrhagic fever" 2,12.
• Multi-Organ Dysfunction: The liver, kidneys, and other organs may fail, leading to shock, anuria (absence of urine), and obtundation (reduced alertness) 2,10,11,12.
• Neurologic and Ocular Complications: Survivors may develop memory loss, uveitis (eye inflammation), and even depression 3,4.

Long-Term Effects in Survivors

Even after recovery, Ebola survivors may face persistent problems:

• Musculoskeletal Pain and Headaches: These can linger for months or even years 3,4.
• Ocular Disorders: Including uveitis and vision problems 3,4.
• Psychological Effects: Depression and post-traumatic stress are not uncommon 4.

Types of Ebola

Ebola is not a single virus, but rather a group of closely related viruses within the Ebolavirus genus. Knowing the differences is crucial, as not all types affect humans equally.

Ebolavirus Species	Human Disease	Geographic Origins	Source
Zaire	Yes (most severe)	Central/West Africa	6,7
Sudan	Yes	East Africa	6,7
Bundibugyo	Yes	Uganda/DRC	6,7
Taï Forest	Rare, mild	Côte d’Ivoire (Ivory Coast)	6,7
Reston	No (humans); Yes (primates)	Philippines/Asia	6,7

Table 2: Ebola Virus Types

The Five Known Ebola Viruses

• Zaire Ebolavirus: The most lethal and best known, responsible for the deadliest outbreaks, including the 2014–2016 West African epidemic 6,7.
• Sudan Ebolavirus: Also causes severe disease in humans, with several outbreaks documented, mainly in Sudan and Uganda 6,7.
• Bundibugyo Ebolavirus: Less common but still a cause of human disease, first identified in Uganda 6,7.
• Taï Forest Ebolavirus: Rare and less severe, with only one known human case 6,7.
• Reston Ebolavirus: Known to infect primates and pigs, but so far not associated with disease in humans 6,7.

Severity and Geographic Range

• Zaire and Sudan ebolaviruses have caused the largest and deadliest outbreaks, with case fatality rates up to 90% for Zaire 7.
• Bundibugyo generally results in lower mortality than Zaire or Sudan types 7.
• Reston is unique for its Asian origin and apparent harmlessness to humans 6.

Causes of Ebola

Understanding how Ebola emerges and spreads is key to controlling outbreaks and protecting communities.

Primary Cause	Transmission Route	Risk Factors	Source
Zoonotic Transmission	Direct contact with body fluids	Caring for ill, Burial practices, Healthcare work	8,9,10,11

Table 3: Causes and Transmission

Zoonotic Origins: Jumping from Animals to Humans

Ebola is considered a zoonotic disease, meaning it originates in animals and occasionally spills over into humans:

• Natural Reservoir: The exact animal reservoir remains unconfirmed, but fruit bats are strongly suspected 11.
• Initial Infection: Most outbreaks begin with a single case of animal-to-human transmission, sometimes from handling or eating bushmeat (wild animals) 11.

Human-to-Human Transmission

Once Ebola enters the human population, it spreads rapidly through:

• Direct Contact: With blood, saliva, vomit, urine, feces, sweat, breast milk, semen, or other body fluids of infected people 11,12.
• Contaminated Objects: Needles, medical equipment, or bedding contaminated with infectious fluids 11.
• Traditional Practices: Funeral and burial rituals, especially where relatives wash or touch the body, are high-risk 8,10.
• Healthcare Settings: Healthcare workers are at high risk without proper protective gear; nosocomial (hospital-acquired) transmission is common in outbreaks 1,8.

Factors Affecting Spread

• Close Quarters: Dense urban areas can accelerate transmission 8.
• Delayed Recognition: Early symptoms are non-specific, leading to late isolation and more secondary cases 1,10.
• Persistence in Survivors: Ebola virus can persist in certain body fluids (notably semen) for months or years after recovery, raising the risk of rare secondary outbreaks 3,4.

Treatment of Ebola

While Ebola was once almost universally fatal, recent advances have revolutionized care and improved survival prospects for those infected.

Approach	Example/Description	Effectiveness	Source
Supportive Care	Fluids, Electrolytes, Oxygen, Organ Support	Reduces mortality	1,10,11
Antivirals	Remdesivir, Favipiravir	Some benefit, under study	14,16,17
Monoclonal Antibodies	MAb114, REGN-EB3, ZMapp	Improved survival	13,15
Vaccines	rVSV-ZEBOV	Prevents infection	11

Table 4: Treatment Modalities

Supportive Care: The Foundation

The primary treatment for Ebola remains supportive care, which includes:

• Rehydration: Managing dehydration caused by vomiting and diarrhea with intravenous fluids 1,10.
• Electrolyte Correction: Balancing salts and minerals lost due to severe gastrointestinal symptoms 10.
• Organ Support: Oxygen, blood pressure support, and sometimes dialysis for kidney failure 10,11.
• Antibiotics/Antimalarials: Used to treat or prevent secondary infections 1.

Early, aggressive supportive care can dramatically improve survival, especially when started promptly 1,10.

Antiviral Therapies: Emerging Options

Several antiviral drugs have been tested:

• Favipiravir: An oral antiviral used in trials, with some evidence of benefit; well tolerated but further studies needed 14,17.
• Remdesivir: An intravenous antiviral with promising results in animal models and early human studies 16.

Monoclonal Antibody Treatments: A Breakthrough

Recent clinical trials have shown that monoclonal antibody therapies can significantly reduce Ebola mortality:

• MAb114 and REGN-EB3: Both have demonstrated superior survival rates compared to previous treatments (like ZMapp and remdesivir) 13.
• ZMapp: Showed some benefit, but recent trials favor the newer monoclonal antibodies 15.

Patients who receive these treatments earlier in the course of their illness have better outcomes 13.

Vaccines: Prevention at Last

The development of the rVSV-ZEBOV vaccine has been a game-changer:

• Prevents Ebola infection: Used successfully in ring vaccination strategies during outbreaks 11.
• Not a Treatment: But critical for outbreak control and protecting healthcare workers 11.

Post-Recovery Care

• Monitoring for Sequelae: Regular check-ups are required for survivors to manage lingering symptoms and complications 3,4.
• Preventing Transmission: Counseling on sexual health and safe practices is important due to viral persistence in semen 3,4.

Conclusion

Ebola virus disease remains a formidable global health challenge, but progress is being made. Understanding its symptoms, types, causes, and the latest treatment options is essential for healthcare workers, policymakers, and at-risk communities.

Main Points Covered:

• Symptoms: Begin suddenly with fever, fatigue, headache, and gastrointestinal distress; severe cases develop hemorrhage, multi-organ failure, and long-term sequelae 1,2,3,4.
• Types: Five known Ebola viruses, with Zaire, Sudan, and Bundibugyo causing most human cases 6,7.
• Causes: Originates in animals (likely bats), spreads through direct contact with body fluids, with healthcare workers and family members at highest risk 8,9,11.
• Treatment: Supportive care is key; new monoclonal antibody therapies (MAb114, REGN-EB3) and vaccines (rVSV-ZEBOV) are improving outcomes and providing hope 10,11,13.

With continued research, improved outbreak response, and global cooperation, the impact of Ebola can be contained—and lives can be saved.