Ebola Virus Disease: Case Fatality Ratio

According to the recent report of WHO [22 August 2014], Case Fatality Ratio (CFR) is of 55-60% (Total number of cases 2615 – Deaths 1427).

WHO Report included data of confirmed, probable, suspect and new patients:

- Confirmed: 1528 Cases and Deaths 844 (CFR 55.2%).
- Probable: 733 Cases and Deaths 440 (CFR 60%).
- Suspect: 354 Cases and Deaths 143 (CFR 40.4%).
- New: 142 Cases and Deaths 77 (CFR 54.2%); Too early to calculate CFR. 
- Total: 2615 Cases and Deaths 1427 (CFR 54.6%).

Considering only confirmed and probable cases (2261 Cases and 1284 Deaths), CFR will be of 56.8%. CFR could not be trustworthy based on these numbers, however this is the largest outbreak with valid number of cases we have.

Of no doubt, we cannot jump to conclusions based on simple calculation of CFR, however this raises an important question; why CFR in the current outbreak is much lower than previous out breaks of Ebola Virus Disease?

Several possible reasons could be the explanation:
1. Virus strain. The current strain could a less virulent than strains isolated from previous outbreaks.
2. The virus is adapting to the human host. Fruit bats are considered the natural hosts for Ebola virus.
3. Patient’s immune system and general health.
4. Early detection of patients and commencement of supportive treatment.

Treatment for Ebola Hemorrhagic Fever

Currently there is no specific treatment for Ebola Hemorrhagic Fever.

Till date, only supportive care is available (intravenous fluids; blood and platelet transfusions), although upcoming human vaccine trials may be promising. The National Institutes of Health (USA) will begin a human vaccine trial in September 2014.

The prospects of transfusing blood or plasma from those patients who have recently recovered from Ebola virus infection seem promising. This could be an effective treatment as Ebola prophylaxis or for use in early onset of Ebola symptoms.

Use of an experimental compound, referred to as BCX4430, was reported in the journal Nature in April 2014. The compound, an RNA-dependent RNA polymerase inhibitor, has proven successful in a nonhuman primate model, whereby postexposure prophylaxis to BCX4430 prevented death in 17 of 18 macaques studied. No human trials have yet been reported.

Ebola Virus is not that lethal as thought before!!!

Since 1976, all epidemiological studies about Ebola Hemorrhagic Fever reported case fatality rate of up to 90%.
According to the last report of WHO (1 August 2014) the case fatality rate is of 55-60% (Total number of cases 1603 – Deaths 887). It is clear that nonspecific treatment with oral rehydration with solutions containing electrolytes or intravenous fluids reduced the case fatality rate.
Could we save lives simply by using oral rehydration with solution containing electrolytes?
Is this the best treatment to avoid hepatic and/or renal failures?

Please check out this site: http://www.who.int/csr/don/2014_08_04_ebola/en/

Virus del Ébola/ Fiebre Hemorrágica del Ébola

Información Básica sobre el Virus del Ébola

Nombre: El virus debe su nombre al rio Ébola en Zaire (actualmente República Democrática del Congo).

Primeros casos: En 1976, se declararon dos brotes simultáneos en Sudán y Zaire.
Enfermedad: Fiebre Hemorrágica del Ébola.
Especias del virus del Ébola: 1) Zaire. 2) Sudán. 3) Bundibugyo. 4) Reston. 5) Tai Forest. Las primeras tres especias son muy virulentas.
Modo de transmisión: Contacto directo con sangre, órganos, secreciones u otros líquidos corporales de personas infectadas. Contacto indirecto con cualquier material contaminado por líquidos corporales de personas infectadas.
Tasa de letalidad: 90%.
Periodo de incubación: 3-21 días (hasta 35-40 días en algunos casos).
Cuadro clínico: Fiebre súbita, dolores musculares, cefalea, dolor de garganta, vómitos, diarrea, erupciones cutáneas y hemorragias (internas y externas). La mortalidad se debe al fallo hepático y/o renal.
Diagnóstico: ELISA y PCR.
Prevención: Medidas generales. Hasta la fecha no hay vacuna (según CDC EE.UU. posible vacuna en Septiembre de 2014).
Tratamiento: No hay ningún tratamiento específico. Tratamiento sintomático: antipiréticos y rehidratación (oral e IV).

Brote/ Epidemia actual de Ébola:
El día 22 de marzo de 2014 el Ministerio de Sanidad de Guinea Conakry notificó a la OMS un brote de enfermedad por virus Ébola.
Hasta el 27 de Julio el número acumulado de casos atribuidos a enfermedad por virus Ébola en Guinea, Liberia, Sierra Leona y Nigeria es de 1.323 incluyendo 729 muertes (letalidad: 55%).

Nota del Ministerio de Sanidad, Servicios Sociales e Igualdad (31 de Julio de 2014): http://www.msssi.gob.es/profesionales/saludPublica/ccayes/alertasActual/docs/Fiebre_hemorragica_Ebola_Guinea_2014(2).pdf

Nota del European Centre for Disease Prevention and Control (17 de Julio de 2014):

http://www.ecdc.europa.eu/en/press/news/_layouts/forms/News_DispForm.aspx?List=8db7286c-fe2d-476c-9133-18ff4cb1b568&ID=1035