Ebola virus disease
Ebola virus disease is a filoviral hemorrhagic fever spread by direct contact with infected body fluids that progresses from a nonspecific febrile illness to diffuse hemorrhage, shock, and multiorgan failure with mortality that can reach 90 percent, and is treated with immediate isolation, supportive care, and a Zaire ebolavirus-specific monoclonal antibody.
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What this article covers
- Overview
A filoviral hemorrhagic fever, most likely to be used as a biologic weapon along with Marburg virus: Ebola and Marburg are the two viral hemorrhagic fevers of greatest bioterrorism concern because of…
- Epidemiology
Endemic transmission occurs where the natural reservoir and vector exposures exist: in endemic areas, spread occurs through vectors, contact with bodily fluids, or fomites.
- Risk factors
Direct contact with the blood, feces, vomit, or other body fluids of an infected person: the essential mode of person-to-person transmission.
- Pathophysiology
Filovirus infection produces a systemic inflammatory and coagulopathic cascade: viral replication triggers a profound inflammatory response with endothelial injury.
- Clinical features
Abrupt onset of fever, headache, and myalgia: the earliest, nonspecific presenting symptoms after the incubation period.
- Differential diagnosis
Malaria: overlapping fever, headache, and myalgia, but distinguished by a history of mosquito exposure in a malaria-endemic area and intraerythrocytic parasites on blood smear rather than hemorrhage as the dominant late feature.
- Diagnosis
Ebola virus disease is confirmed by antigen and antibody assays and polymerase chain reaction of blood, with the specific test depending on the stage of infection; there is no separate formal…
- Management
First, place the patient in strict isolation with contact and droplet precautions before any further evaluation: protecting healthcare workers and other patients is the immediate priority given the…
- Complications
Shock: from combined hemorrhage and capillary leak; the proximate cause of death in most fatal cases.
- Prognosis
Mortality can reach 90%: among the highest case fatality rates of any recognized human infection, though early aggressive supportive care and prompt monoclonal antibody therapy for confirmed Zaire ebolavirus infection reduce that risk.
- Prevention
Vaccinate at-risk contacts and healthcare workers with the vaccine strictly indicated for Zaire ebolavirus: the only species with an established preventive vaccine; it does not cover other Ebola…
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- Isolation precautions
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- Leptospirosis
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- Malaria
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- Measles
Measles (rubeola) is a highly contagious paramyxovirus infection that has re-emerged in the United States because of low vaccination rates, presenting with a prodrome of the 4 C's followed by a cephalocaudal maculopapular rash, confirmed by PCR or IgM, and managed with supportive care plus vitamin A.
- West Nile virus infection
West Nile virus (WNV) is a mosquito-borne flavivirus and the most common cause of epidemic viral encephalitis in the United States, transmitted by Culex mosquitoes between June and October. Most infections are asymptomatic, but neuroinvasive disease can present as meningitis, encephalitis with basal ganglia involvement (tremor, parkinsonism, myoclonus), or acute flaccid paralysis resembling poliomyelitis; diagnosis is by WNV IgM in serum or CSF, and treatment is supportive because no specific antiviral or vaccine exists.
- Anthrax
Anthrax is caused by Bacillus anthracis spores acquired by inhalation, cutaneous inoculation, or ingestion, with cutaneous disease most common and inhalational disease most lethal. Systemic disease is treated with ciprofloxacin or doxycycline plus additional agents and antitoxin for 60 days, and any inhalational case is a bioterrorism sentinel event requiring immediate public health notification.