Ebola hemorrhagic fever
Ebola hemorrhagic fever (Ebola HF) is a severe viral illness caused by the Ebola virus, which belongs to the Filoviridae family. This disease is characterized by its high mortality rate, with between 50% to 90% of infected individuals succumbing to the illness. The virus is primarily transmitted through direct contact with the body fluids of infected individuals or animals, with outbreaks mainly occurring in sub-Saharan Africa. Symptoms typically appear within two to twenty-one days after exposure and can include fever, muscle pain, vomiting, and severe bleeding from various body parts.
Diagnosis of Ebola HF relies on clinical symptoms and laboratory blood tests, as there is no routine screening available. Treatment is primarily supportive, focusing on hydration, managing symptoms, and preventing complications, as there is currently no proven cure. Preventive measures include avoiding exposure to known risk areas and practicing safe burial and care practices for the deceased and infected individuals. Vaccines have been developed for certain strains of the Ebola virus and are being administered in at-risk populations to help prevent future outbreaks. Despite ongoing research and the development of therapeutic options, Ebola remains a significant public health concern, with recent outbreaks underscoring the need for continued vigilance and education in affected regions.
Ebola hemorrhagic fever
- ANATOMY OR SYSTEM AFFECTED: Blood
- ALSO KNOWN AS: Viral hemorrhagic fever
Definition
Ebola hemorrhagic fever is a condition caused by the Ebola virus, leading to a serious disease that has an extremely high mortality rate. This condition is spread by contact with the body fluids of an infected person or animal, even after death, and can be spread in research laboratories from infected animals. The Ebola virus, which occurs naturally in sub-Saharan Africa, damages the lining of blood vessels and interferes with blood clotting. Ebola hemorrhagic fever appears in sporadic outbreaks.
Causes
Ebola hemorrhagic fever is caused by a virus from the family Filoviridae and the genus Ebolavirus. There are five species of the virus: Zaire, Sudan, Cote d’Ivoire, Bundibugyo, and Reston. Reston and Cote d’Ivoire cause relatively mild symptoms and are usually not fatal. Zaire, Sudan, and Bundibugyo appear to be the cause of Ebola hemorrhagic fever. These species originate in the rainforests of Africa and reside in an unknown host. Less commonly, Reston appears in the western Pacific in the Philippines. While Ebola is still being studied, scientists believe fruit bats are a main wild host and potential source of the Ebola virus.
Risk Factors
The main risk factor is direct contact with the body fluids of infected persons or animals. Other risk factors for Ebola hemorrhagic fever are living in or visiting areas where the Ebola virus is found, working in a laboratory where animal testing with the Ebola virus is being conducted, and caring for persons with Ebola virus infection. Additional risk factors for contracting Ebola include taking part in traditional burial practices for those infected by the disease and preparing and eating contaminated meat. The Ebola virus can also be passed through breastfeeding if the mother has been infected.
Symptoms
The incubation period for Ebola hemorrhagic fever ranges from two to twenty-one days after exposure. During this time, the infected person can have joint and muscle pain, low back pain, chills, a fever, diarrhea, a headache, malaise, nausea, vomiting, and a sore throat. The disease then rapidly progresses to symptoms of bleeding from the eyes, ears, nose, mouth, and rectum; internal bleeding; depression; conjunctivitis; swelling of the genitalia; skin pain; a body-wide rash; stomach pain; seizures; coma; and delirium. Between 50 and 90 percent of persons who contract Ebola hemorrhagic fever will die from the condition.
Screening and Diagnosis
There is no routine screening for Ebola hemorrhagic fever. The isolated geographic areas where the disease occurs affect diagnosis, often delayed because of a lack of medical care or inadequate medical care. Diagnosis is achieved through symptoms and blood tests, including complete blood count, blood electrolytes, blood coagulation tests, and identification of the virus or antibodies to the virus. If a person is infected, their blood cell counts will be low, electrolytes will be decreased, and blood coagulation rate will be decreased. The virus or its antibodies are tested using antigen-capture enzyme-linked immunosorbent assay or polymerase chain reaction.
Treatment and Therapy
There is no cure for Ebola hemorrhagic fever. Existing antiviral medications do not seem to be effective against this virus. The treatment for Ebola hemorrhagic fever is intensive and supportive care. This care includes intravenous fluids and blood transfusions, replacing electrolytes and blood coagulation factors, oxygen, maintaining blood pressure with medications, and treating complications, such as infections.
The treatments used are based on the symptoms and blood tests of the infected person. Blood transfusions from Ebola fever survivors to persons with Ebola have been tried. Because the survivor's blood has antibodies to the virus, experts believe this blood could assist the infected person in fighting the disease. There is limited data, however, on the effectiveness of this treatment.
Monoclonal antibodies, artificially constructed proteins that can target and neutralize the Ebola virus, have been developed. Although these treatments have only been approved for Ebola cases in the United States, they have shown promise in clinical laboratory tests. Several additional experimental therapies continued to be studied.
Prevention and Outcomes
The only way to prevent Ebola hemorrhagic fever is to avoid places where the virus is known to occur. This includes Africa, the Philippines, and laboratories that perform animal testing with viruses. Caretakers of infected persons and workers in viral-testing animal laboratories should always wear personal protective clothing, such as a gown, gloves, goggles, and a facial mask.
Education of persons living in areas where the Ebola virus resides can limit the spread of the disease. This education consists of teaching villagers to avoid unprotected contact with persons who have or had the disease, whether living or dead. It also includes teaching villagers to avoid unprotected contact with dead animals in cases in which the cause of death is unknown.
Two vaccines for the Ebola virus—one for the Zaire strain and another for the Sudan strain—have been approved. These vaccines were being administered to at-risk populations in the hopes of preventing future outbreaks. Limiting exposure to the Ebola virus remains the most effective way to avoid contracting it. Still, Ebola outbreaks remained a vital public health issue. A large outbreak of Ebola between 2014 and 2016 impacted over 28,000 individuals and had international implications. Despite the medical advances being made against the Ebola virus, outbreaks continued to occur, such as the wave that spread across Uganda in late 2022 and early 2023.
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