he US Food and Drug Administration (FDA) has granted emergency authorization for two new tests for detecting Ebola in humans. The tests, which can detect Ebola in blood or urine samples in 1 hour, can be performed on-site in hospitals with the proper lab equipment from the tests’ manufacturer, BioFire Defense. In other tests, samples must be sent from hospitals to be run in specialized labs and require 24-48 hours to produce results. Emergency use authorizations by the FDA permit the use of unapproved medical products in dealing with life-threatening illnesses when no approved or available alternatives exist.[1]
Signs and symptoms
The following 2 types of exposure history are recognized:
Primary exposure – This typically involves travel to or work in an Ebola-endemic area
Secondary exposure – This refers to human-to-human exposure (eg, medical caregivers, family caregivers, or persons who prepared deceased patients for burial), primate-to-human exposure (eg, animal care workers who provide care for primates), or persons who collect or prepare bush meat for human consumption
Physical findings depend on the stage of disease at the time of presentation. With African-derived Ebolavirus infection, there is an incubation period (typically 3-8 days in primary cases and slightly longer in secondary cases).
Early findings may include the following:
Fever
Pharyngitis
Severe constitutional signs and symptoms
Maculopapular rash (best seen in white patients)
Bilateral conjunctival injection
Later findings may include the following:
Expressionless facies
Bleeding from intravenous (IV) puncture sites and mucous membranes
Myocarditis and pulmonary edema
In terminally ill patients, tachypnea, hypotension, anuria, and coma
Survivors of Ebola virus disease have developed the following late manifestations:
Myalgias
Asymmetric and migratory arthralgias
Headache
Fatigue
Bulimia
Amenorrhea
Hearing loss
Tinnitus
Unilateral orchitis
Suppurative parotitis
See Clinical Presentation for more detail.
Diagnosis
Diagnostic studies that may be helpful include the following:
Basic blood tests – Complete blood count (CBC) with differential, bilirubin, liver enzymes, blood urea nitrogen (BUN), creatinine, pH
Studies for isolating the virus – Tissue culture (only to be performed in one of a few high-containment laboratories throughout the world), reverse-transcription polymerase chain reaction (RT-PCR) assay
Serologic testing – Enzyme-linked immunosorbent assay (ELISA) for antigens or for immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies
Other studies – Immunochemical testing of postmortem skin, electron microscopy
See Workup for more detail.
Management
General principles of care are as follows:
Supportive therapy with attention to intravascular volume, electrolytes, nutrition, and comfort care is of benefit to the patient
Such therapy must be administered with strict attention to barrier isolation; all body fluids contain infectious virions and should be handled with great care
No specific therapy is available that has demonstrated efficacy in the treatment of Ebola hemorrhagic fever
There are no commercially available Ebola vaccines; however, neutralizing antibodies have been studied that may be useful in vaccine development or as passive prophylactic agents
At present, no specific anti-Ebolavirus agents are available. Agents that have been studied for the treatment or prevention of Ebola virus disease include the following:
Ribavirin (possesses no demonstrable anti-Ebolavirus activity in vitro and has failed to protect Ebolavirus -infected primates)
Nucleoside analogue inhibitors of S-adenosylhomocysteine hydrolase (SAH)
Interferon beta
Horse- or goat-derived immune globulins
Human-derived convalescent immune globulin preparations
Recombinant human interferon alfa-2
Recombinant human monoclonal antibody against the envelope glycoprotein (GP) of Ebola virus
DNA vaccines expressing either envelope GP or nucleocapsid protein (NP) genes of Ebola virus
Activated protein C[2]
Recombinant inhibitor of factor VIIa/tissue factor[3]
In those patients who do recover, recovery often requires months, and delays may be expected before full resumption of normal activities. Weight gain and return of strength are slow. Ebola virus continues to be present for many weeks after resolution of the clinical illness.
