One reason I know that I went into the right speciality is that we HAVE to know about Ebola. Virology is uber fascinating, and we aim to hammer out everything the EP provider needs to know regarding this Ebola virus disease (EVD).
Aside from being an interesting topic, there is currently a budding outbreak of ebola in the congo. See news article below.
(note: I wrote this for a departmental memo in 2018)
Now the outbreak is worsening: https://www.apnews.com/49fcb435740b4c5b88bab2a1c873b763
So it is even more important for the EP to keep this disease on their radar.
If you recall from the last outbreak, there were several notable US cases, one of which received treatment in NYC.
It is thought that there is animal reservoir (likely fruit bats) and the animal to human transmission of the virus may come from individuals handling bushmeat.
Ebola is a filovirus (meaning it looks like a string). It is a negative sense single stranded RNA virus.
Below is a colorized scanning electron microscope image of the virus (curtesy wikimedia commons)
Transmission is via contact of viral particles to mucus membranes or broken down skin.
Incubation time is 9-11 days.
The ebola virus is one of the most infectious agents known to man. A single ebola virion is enough to be infectious. This is in stark contrast to most other infectious agents which typically require a large inoculum to cause clinically significant disease.
Symptoms typically develop by infection day 5:
- -fever, fatigue
- GI upset: vomiting, watery diarrhea, abdominal pain
- this can progress to seizures and cerebral edema
- renal failure
- hepatic failure
- ecchymoses and petechial rash are also possible
- hemorrhage is uncommon, but reported in 18% of patients (typically GI)
Patients with severe disease typically die within 6-16 days. Mortality rate in west Africa was ~40-70%. Of 27 patients treated in the United States, the fatality rate was 18.5%.
The mechanism for the hemorrhagic fever is thought to be massive activation of macrophages and other immune cells causing a cytokine storm, which then leads to break down of the vascular endothelium and results in leaking. Other research suggests the virus itself has proteins which lead to endothelial dysfunction and leakage.
You can utilize ELISA, PCR, or virus isolation to test for the disease. These tests are only available in consultation with a governmental health agency.
Mainstay of treatment is supportive. However, you can transfuse convalescent serum from recovered and now immune individuals. A more elegant and certainly more expensive treatment is ZMapp, which is a mix of “3 humanized monoclonal antibodies” against Ebola. There also several vaccines including rVSV-ZEBOV which have been experimentally deployed in west Africa.
As per the CDC, travelers from endemic outbreak regions should self monitor their health for 21 days. Febrile patients who may had contact with ebola, should be placed on contact precautions and NYDOH should be immediately contacted.
Hopefully this is something we never see. But preparedness is critical for our specialty. Thank you for taking the time to read and have a great day.
References:
Bah EI, Lamah MC, Fletcher T, et al. Clinical presentation of patients with Ebola virus disease in Conakry, Guinea. N Engl J Med. 2015;372(1):40-7.
Cantoni D, Rossman JS. Ebolaviruses: New roles for old proteins. PLoS Negl Trop Dis. 2018;12(5):e0006349.
https://www.cdc.gov/vhf/ebola/healthcare-us/preparing/clinicians.html
https://commons.wikimedia.org/wiki/File:Ebola_virus_virion.jpg
Sanford guide, app on iOS
Zwart MP, Hemerik L, Cory JS, et al. An experimental test of the independent action hypothesis in virus-insect pathosystems. Proc Biol Sci. 2009;276(1665):2233-42.