Ebola virus disease, previously referred to as Ebola haemorrhagic fever, is a severe and often lethal illness that affects both humans and other primates. The virus is transmitted from wild animals, including fruit bats, porcupines, and non-human primates, to humans through direct contact with their bodily fluids such as blood, secretions, organs, and contaminated surfaces such as clothing and bedding.
The fatality rate for EVD cases is approximately 50%, with previous outbreaks having rates ranging from 25% to 90%. Initially, the disease was observed in remote villages close to tropical rainforests in Central Africa. However, the 2014-2016 West African outbreak, which began in Guinea and spread to Sierra Leone and Liberia, was the most significant and complex Ebola outbreak to date, surpassing all other outbreaks in terms of cases and deaths.
It is believed that fruit bats from the Pteropodidae family serve as natural hosts for the Ebola virus.
Symptoms
The time period between becoming infected with Ebola and exhibiting symptoms is called the incubation period, which lasts from 2 to 21 days. Ebola cannot be transmitted by an infected person until they display symptoms.
Symptoms of Ebola virus disease (EVD) may appear suddenly and consist of fever, tiredness, muscle pain, headache, and sore throat. Subsequently, there may be vomiting, diarrhea, rash, indications of kidney and liver dysfunction, and in severe cases, both internal and external bleeding (e.g., bleeding gums, bloody stools). Diagnostic tests have been created to verify the existence of the virus, although it can be challenging to differentiate EVD from other infectious illnesses like malaria, typhoid fever, and meningitis.
Treatment and prevention
Survival rates can be improved by providing supportive care such as rehydration with oral or intravenous fluids, and addressing specific symptoms. Several treatments are being evaluated, including blood products, immune therapies, and drug therapies.
During the 2018-2020 Ebola outbreak in the Democratic Republic of the Congo (DRC), a randomized control trial was conducted to assess the effectiveness and safety of drugs used to treat Ebola patients, with an ethical framework created in collaboration with experts and the DRC.
The US Food and Drug Administration authorized two monoclonal antibodies, Inmazeb and Ebanga, for the treatment of Zaire ebolavirus infection in both adults and children in late 2020. The Ervebo vaccine has been shown to be effective in protecting people against the Zaire ebolavirus and is recommended by the Strategic Advisory Group of Experts on Immunization as part of a broader set of Ebola outbreak response tools. The vaccine was authorized for use by the US Food and Drug Administration in December 2020 and prequalified by WHO for individuals aged 18 and above, except for pregnant and breastfeeding women.
In May 2020, the European Medicines Agency suggested approving a two-component vaccine, Zabdeno-and-Mvabea, for individuals aged one and above. The vaccine is administered in two doses, with Zabdeno being given first and Mvabea around eight weeks later as a second dose. However, this prophylactic two-dose regimen is not suitable for immediate protection during an outbreak response.
