Untreated Ebola virus disease (EVD) has a 70-90% fatality rate. The virus has intensely affected the lives of those connected to outbreaks of the infection. Today, ongoing research and development have yielded some milestones that will begin to reshape public health preparedness and response.
Patients with EVD commonly begin to show symptoms 8 to 12 days postexposure, with an incubation period of 2 to 21 days. Initial signs and symptoms are often nonspecific and may include fever, chills, myalgia, and malaise. Symptom progression typically occurs within 5 more days, evolving into gastrointestinal issues such as severe watery diarrhea, nausea, vomiting, or abdominal pain. Patients may also have chest pain, shortness of breath, headache, confusion, conjunctival injection, hiccups, seizures, or cerebral edema. Bleeding can sometimes manifest as petechiae, ecchymosis/bruising, oozing from venipuncture sites, and mucosal hemorrhage. A diffuse erythematous maculopapular rash (usually involving the neck, trunk, and arms) may develop by days 5 to 7. There is also a risk for spontaneous miscarriage in pregnant women.
The pathogenesis involves Ebola virus entering through mucous membranes, breaks in the skin, or parenteral exposure. It infects multiple cell types, including monocytes, macrophages, dendritic cells, endothelial cells, fibroblasts, hepatocytes, adrenal cortical cells, and epithelial cells. There may be a relationship between the incubation period and the infection route (eg, 6 days for injection vs 10 days for contact). From the initial infection site, Ebola virus migrates to regional lymph nodes and then to the liver, spleen, and adrenal glands. Lymphocytes undergo apoptosis, resulting in decreased lymphocyte counts. Hepatocellular necrosis can occur, which is associated with clotting factor dysregulation and subsequent coagulopathy. It is also possible to find adrenocortical necrosis, which is associated with hypotension and steroid synthesis impairment. Multiorgan failure and shock typically result from the vascular leaking and impairment of clotting that occurs after the virus triggers a release of proinflammatory cytokines.
A boon for protection against EVD arrived with its first vaccine's approval on December 19, 2019. Ervebo
(recombinant vesicular stomatitis virus–Zaire Ebola virus [rVSV-ZEBOV], or Ebola Zaire vaccine, live) is a sterile suspension for intramuscular injection consisting of a vesicular stomatitis virus (VSV) backbone deleted for the VSV envelope glycoprotein and substituted with the envelope glycoprotein of the Zaire ebolavirus. Ervebo is indicated for the prevention of EVD in individuals aged 18 years and older. Ervebo is a suspension for injection supplied as a 1mL dose in single-dose vials.
The most recent milestone for battling EVD came on October 14, 2020, with the FDA approval of Inmazeb
. This drug is a combination of Zaire ebolavirus
glycoprotein-directed human monoclonal antibodies (atoltivimab/maftivimab/odesivimab), indicated for the treatment of infection caused by Zaire ebolavirus
in adult and pediatric patients, including neonates born to a mother who is RT-PCR positive for Zaire ebolavirus
infection. The recommended dosage of Inmazeb is 50mg atoltivimab/50mg maftivimab/50mg odesivimab per kg, diluted and administered as a single intravenous infusion.
These landmark approvals are vital advancements in EVD preparedness. Direct guidance and recommendations
for healthcare professionals are available from the CDC. For patients with questions about Ebola stemming from heightened concerns about viruses due to the current COVID-19 pandemic, the CDC has created an infographic entitled, "Is it COVID-19 or Ebola?
" that can be helpful as a part of patient engagement during counseling conversations.