Ebola natural history
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Ebola natural history On the Web |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Michael Maddaleni, B.S.; Guillermo Rodriguez Nava, M.D. [2] João André Alves Silva, M.D. [3]
Overview
Ebola infection rapidly progresses to death in the absence of supportive care. Ebola infection can be complicated by multiorgan failure and shock. Mortality rates, depending on the viral strain, can range between 25% - 90%.[1]
Natural History
The symptoms of Ebola hemorrhagic fever usually develop 2 to 21 days following exposure to Ebola virus. Early symptoms include high-grade fever, chills, myalgias, and generalized fatigue. Without treatment, patients subsequently develop multisystem symptoms, including nasal discharge, cough, abdominal pain, nausea, vomiting, chest pain, and dyspnea.
Ebola infection commonly occurs from direct contact with the virus through mucosal surfaces, cuts on the skin or parenterally. The risk of infection is increased when there is contact with patients or cadavers infected by the virus. It commonly takes 2 - 21 days for symptoms to develop with earlier symptoms associated with worse outcomes. Death occurs in approximately 50% of patients between the 6 and 16 days from the onset of the disease classically from multiorgan failure and shock.
Although different species of Ebola virus have different clinical manifestations, a common progression of symptoms includes 2 phases:[2][3][4] an incubation period (2 - 21 days) with fever, myalgias and non-specific systemic symptoms followed by an abrupt onset of hemorrhagic signs and symptoms; a short pseudoremission period lasting approximately 24 - 48 hours may be observed.
Complications
Patients who survive Ebola infection may have the following complications:[4]
- Myalgias
- Headache
- Tinnitis
- Hearing loss
- Psychosis
- Myelitis
- Recurrent hepatitis
- Amenorrhea
- Unilateral orchitis
- Suppurative parotitis
- Shock
Prognosis
- Ebola infection is associated with poor survival. Mortality rates depend on the species of virus:[4]
- Zaire Ebola virus species - mortality rate of 60 - 90%
- Sudan Ebola virus species - mortality rate 40 - 60%
- Bundibugyo Ebola virus species - mortality rate 25%
- Côte d’Ivoire Ebola virus - mortality rate 0%, with only 1 case reported, who survived
- Patients who survived Ebola infection for two weeks are usually able to recover slowly, despite potential complications.[4]
- Survival for 11 days is generally associated with recovery.
- Desquamation of the maculopapular rash by the 5th or 7th day is often associated with survival.[4]
- Tachypnea is the strongest correlate of fatal outcome. It often appears a few hours before death. Other correlates of fatal outcome are hypotension, tachycardia and anuria.
- Severe hemorrhagic complications such as hematemesis, melena, epistaxis, ear bleeding and hematuria are associated with a poorer prognosis and are often associated with death within a week.[5]
- In pregnant women there is an increased risk of miscarriage.[4]
References
- ↑ "CDC Ebola Hemorrhagic Fever Information Packet" (PDF). April 2010.
- ↑ Ndambi R, Akamituna P, Bonnet MJ, Tukadila AM, Muyembe-Tamfum JJ, Colebunders R (1999). "Epidemiologic and clinical aspects of the Ebola virus epidemic in Mosango, Democratic Republic of the Congo, 1995". J Infect Dis. 179 Suppl 1: S8–10. doi:10.1086/514297. PMID 9988156.
- ↑ Bwaka MA, Bonnet MJ, Calain P, Colebunders R, De Roo A, Guimard Y; et al. (1999). "Ebola hemorrhagic fever in Kikwit, Democratic Republic of the Congo: clinical observations in 103 patients". J Infect Dis. 179 Suppl 1: S1–7. doi:10.1086/514308. PMID 9988155.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 Feldmann H, Geisbert TW (2011). "Ebola haemorrhagic fever". Lancet. 377 (9768): 849–62. doi:10.1016/S0140-6736(10)60667-8. PMC 3406178. PMID 21084112.
- ↑ Sureau PH (1989). "Firsthand clinical observations of hemorrhagic manifestations in Ebola hemorrhagic fever in Zaire". Rev Infect Dis. 11 Suppl 4: S790–3. PMID 2749110.