Apart from other microscopic organisms like bacteria, fungi, and protozoa, there is another tiniest entity that the naked eye cannot see, it can only survive inside the living cells of the host, found in realms of the microbial world, and that creature is labeled as a virus. These viruses can infect humans and other biotic components, including plants, animals, and even bacteria. These viruses damage host tissues and cause severe illnesses that are often fatal. One of these viruses is Ebola, first identified in 1976 when outbreaks were recorded in central Africa, in the village of Congo near river Ebola, which gave name to these viruses as Ebola viruses.
What is Ebola?
Ebola is a disease caused by four out of six viruses belonging to the genus Ebola. It is characterized by moderate to intense life-endangering conditions that affect the majority of the systems of the body, which can consequently lead to viral hemorrhagic fever (VHF) in animals. Yellow fever, Rift Valley fever, dengue fever, Crimean-Congo fever, and Ebola disease are various forms of viral hemorrhagic fevers. VHF targets body organ systems, including damage to the liver, disturbing the bone-marrow functioning, and causing disseminated intravascular coagulation (DIC) blockage of blood vessels due to the formation of small blood clots throughout the body. DIC is thought to be the reason for internal and external bleeding from the body. Because of these conditions, Ebola disease is also named Ebola virus disease (EVD) or Ebola hemorrhagic fever (EHF).
How does Ebola virus transmission occur from animals to humans?
Along with arthropods, rodents, and birds, the most common natural reservoirs of Ebola virus are fruit bats. The three types of fruit bats, including Hypsignathus monstrous, Epomops franqueti, and Myonycteris torquata, can carry this virus without being infected by this lethal Ebola disease. Animals become infected by eating any leftover meal, such as fruit or meat previously eaten by a fruit bat carrying viruses.
How Does the Ebola Virus Transmit From Person to Person?
Humans can catch this virus by coming in direct contact with an infected animal’s feces or body fluids. The virus transmits from person to person through contact with broken skin, body fluids, or mucus membranes in the eyes, nose, or mouth.
This virus enters inside a new host when a healthy individual comes in direct contact with blood or body fluids such as urine, saliva, feces, vomit, breast milk, amniotic fluid, and semen of a person who is already suffering from EVD. World health organization (WHO) stated that the virus cannot be transmitted through sweat.
The Ebola virus can survive in dried form on any object’s surface. Fomites are non-living objects such as clothes, bed sheets, needles, or other medical instruments. Fomites contaminated with an infected person’s blood or body fluids also serve as transmission sources of EVD.
Breast milk and semen may have the chance to contain the Ebola virus even if the person has recovered from the disease.
Unlike viruses, no cases of Ebola virus transmission were recorded through water, air, food, or mosquitoes.
Ebola Virus Outbreaks
The Ebola virus was first identified in 1976. Since then, 2,387 cases have been confirmed, with 1,590 fatalities till 2013.
A major outbreak occurred in West Africa in 2014. In this epidemic, almost 40% of the casualties were documented in Guinea, Liberia, and Sierra Leone. Subsequently, in September 2014, the first person who flew from Liberia to Texas developed symptoms of this lethal disease and died within ten days. This was the first case of Ebola virus diagnosed in the United States of America. Additionally, a few people caught this infection, and this way, the Ebola virus began to spread outside of Africa and began affecting people in the USA. Following this, another Ebola virus outbreak was recorded from May to July 2017, declared an epidemic of Ebola hemorrhagic fever by the World Health Organization (WHO). Similarly, WHO declared the 2019 Ebola virus outbreak in DRC a world health emergency.
More than ten outbreaks were documented from 2014–2022 in several regions of DRC, including North Kivu and Equateur province. The latest Ebola virus outbreak was recorded in Uganda in September 2022. This outbreak lasted four months, from September 2022 to January 2023. During this outbreak, 80 confirmed deaths were reported because of the Ebola virus.
The Ebola virus affected numerous countries since its first appearance in 1976, including Italy, Mali, the United Kingdom, the United States, Spain, Nigeria, and Senegal.
Symptoms of Ebola Virus Disease
Ebola virus disease frequently causes death. The estimated incubation period of Ebola is from 2 to 21 days. Early stages include dry symptoms of flu-like conditions such as lethargy, chills, sore throat, fever of 38.6 oC or greater, myalgia, or muscle pain. Later wet symptoms also start to show, like nausea, vomiting, diarrhea, stomach pain, and hiccups, eventually leading to loss of fluids and cause dehydration. Rashes develop in almost half of the cases of EVD. Later, internal or external bleeding begins after five to seven days of dry and wet symptoms. Ebola patients have been reported to have reduced blood clotting, which leads to bleeding from the eyes, ears, or nose. Other conditions include blood in cough, vomit, and stool. The gastrointestinal tract, mainly the rectum, shows heavy bleeding in fewer cases. If the patient is kept under proper care and the immune system is strong enough to combat the deadly Ebola virus. Recovery is possible between 7 to 14 days from the appearance of the first symptom. Patients who survive EVD develop antibodies against the virus, which remain in the body for at least ten years.
However, if there is a significant loss of fluids and heavy bleeding from the organs, coma, and death may occur within 6 to 16 days from the appearance of the first symptom.
Diagnosis of Ebola Virus Disease
The symptoms of the Ebola virus are often misdiagnosed due to their resemblance to the symptoms of other infections, including malaria, dengue, and typhoid fever. Therefore, diagnosing the Ebola virus can be challenging; however, samples of body fluids extracted from infected patients are subjected to laboratory tests, including antibody detection in the patient’s blood, virus-cell culturing, RNA or protein detection through real-time polymerase chain reaction (RT-PCR), or virus-specific proteins identification through enzyme-linked immunosorbent assay, in short ELISA. Cell culturing, RT-PCR, and ELISA have high sensitivity and specificity and are feasible irrespective of the viral infection stage, whereas antibodies such as IgM and IgG detection tests are more reliable in later stages of the disease. Likewise, although cell culturing is a reliable virus detection method, it is laborious and time-consuming, hence cannot be a feasible choice during EVD outbreaks.
Treatment of Ebola Virus Disease
The Food and drug administration (FDA) in the United States approved two therapeutic drugs, Inmazeb and Ebanga in October and December 2020, respectively, for treating patients with Ebola hemorrhagic fever. These drugs consist of monoclonal antibodies specifically to glycoproteins on the surface of the Ebola virus. These drugs have enhanced the rate of survival in patients with Ebola virus disease.
Supportive care includes intravenous injection of fluids and salts, blood transfusions, use of medicines to treat other infections, maintain blood pressure, and control fluid loss volume through vomiting and diarrhea.
Prevention Strategies To Avoid EVD
A vaccine named Ervebo is designed to protect the people who dwell in countries with a high risk of Ebola. Besides, the Centers for Disease Control and Prevention (CDC) issued preventive measures to protect yourself from catching this lethal disease. These preventions include:
- Avoid coming in contact with the blood or body fluids of the infected person.
- Using alcohol-based handwash or soap to wash hands.
- Avoid touching bed sheets, clothing, and medical equipment used by an infected person.
- Always wear personal protection equipment (PPE) whenever going near the patients or visiting the hospitals treating Ebola patients.
- Disinfecting the surfaces with sodium hypochlorite or calcium hypochlorite to eliminate the presence of viruses on fomites.
- Avoid touching the dead body of a person who has died from EVD. Burning the dead body can be an alternate option instead approaching traditional burying rituals.
Final Thoughts
Ebola, a disease which has symptoms that have close resemblance to other infections like typhoid, malaria and meningitis. Among six various species of Ebola, only four of them are capable of causing infection in humans. Ebola virus interferes with the blood clotting system of human body which causes internal bleeding due to rupturing of blood vessels. Touching infected person’s body fluids or fomites that are contaminated with Ebola virus is reason behind catching this deadly infection. If not treated carefully and not given basic aid, this viral disease can lead to fatal consequences.
About the author
Dr. Madilyn Adams is a PhD in molecular medicine from Harvard University and has been working as a medical blogger for seven years.
References
- https://www.mountsinai.org/health-library/diseases-conditions/ebola-virus-disease#:~:text=Ebola%20is%20a%20severe%20and,%2C%20monkeys%2C%20and%20chimpanzees).
- https://www.hopkinsmedicine.org/health/conditions-and-diseases/ebola
- https://www.who.int/news-room/fact-sheets/detail/ebola-virus-disease
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4205154/
- https://www.cdc.gov/vhf/ebola/symptoms/index.html
