Ebola!

Ebola (pictured right) is an RNA filovirus in the family Filoviridae, genus Ebolavirus. Ebola was first discovered in 1976 in the Democratic Republic of the Congo. Of the five species, four cause serious disease in humans and one only causes disease in nonhuman primates. Ebolavirus is spread through direct person-to-person (or primate-to-primate) contact with blood, secretions, organs or bodily fluids of infected patients.

Ebolavirus infection is fatal in 50-90% of cases, with some strains less virulent (50-60%) and others more virulent (80-90%). Symptoms appear 2-21 days post-exposure with a rapid onset. Initial symptoms are flu-like, but quickly progress to more serious symptoms such as chest pain, red eyes, skin rash, jaundice, hiccups, or bleeding. Laboratory findings of interest are low WBC/platelet counts with elevated liver enzymes. Definitive diagnosis of ebolavirus occurs through ELISA, antigen detection or serum neutralization tests, RT-PCR assays, electron microscopy, or viral culture.

The virus produces proteins that increase blood vessel permeability, causing hemorrhage. Ebolavirus may also prevent the body from mounting an appropriate immune response through an unknown mechanism. One theory is that the virus overwhelms the immune system using a cytokine storm, sending the patient into shock. Another theory is the virus prevents the immune system from mounting a response at all by reducing interferon activity within the cells (normally, this activity would signal NK cells or T cells that a cell has been taken over by a virus and mark it for destruction).

Unfortunately, there is no treatment for ebolavirus, but a vaccine is in clinical trials. Infected patients are placed into quarantine and receive supportive therapy, such as pain medicine or fluids. Death results from pulmonary or gastrointestinal hemorrhage, hepatitis, or encephalitis one to two weeks after the onset of symptoms. Patients who recover may remain infectious for several weeks after symptoms clear.

References
Picture: http://edwardmd.files.wordpress.com/2013/11/ebola1.jpg
1. Basler Christopher, et al. The Ebola Virus VP35 Protein Inhibits Activation of Interferon Regulatory Factor 3. Journal of Virology. July 2003: 88(11).
2. CDC. Ebola Hemorrhagic Fever. CDC Viral Hemorrhagic Fevers. 2014. Available at: http://www.cdc.gov/vhf/ebola/. Accessed May 16, 2014.
3. Federation of American Scientists. Ebola Fact Sheet. FAS Biosecurity Fact Sheets. Available at: http://www.fas.org/programs/ssp/bio/factsheets/ebolafactsheet.html. Accessed May 16, 2014.
4. Villinger Francois, et al. Markedly Elevated Levels of Interferon (IFN)-y, IFN-a, Interleukin (IL)-2, and Tumor Necrosis Factor-a Associated with Fatal Ebola Virus Infection. The Journal of Infectious Diseases. 1999: 179 pp S188-S191.
5. WHO. Ebola virus disease. WHO Media Centre Fact Sheets. 2014. Available at: http://www.who.int/mediacentre/factsheets/fs103/en/. Accessed May 16, 2014.