What causes Ebola hemorrhagic fever?

The cause of Ebola hemorrhagic fever is Ebola virus infection that results in coagulation abnormalities, including gastrointestinal bleeding, development of a rash, cytokine release, damage to the liver, and massive viremia (large number of viruses in the blood) that leads to damaged vascular cells that form blood vessels. As the massive viremia continues, coagulation factors are compromised and the microvascular endothelial cells are damaged or destroyed, resulting in diffuse bleeding internally and externally (bleeding from the mucosal surfaces like nasal passages and/or mouth and gums and even from the eyes [termed conjunctival bleeding]). This uncontrolled bleeding leads to blood and fluid loss and can cause hypotensive shock that causes death in many Ebola-infected patients.

What are risk factors for Ebola hemorrhagic fever?

The risk factors for Ebola hemorrhagic fever are travel to areas where Ebola infections (see current CDC travel advisories for African countries) have been reported. In addition, association with animals (mainly primates in the area where Ebola infections have been reported) is potentially a risk factor according to the CDC. Another potential source of the virus is eating "bush meat." Bush meat is the meat of wild animals, including hoofed animals, primates, and rodents. Currently, evidence for any airborne transmission of this virus is lacking. During Ebola hemorrhagic fever outbreaks, health-care workers and family members and friends associated with an infected person are at the highest risk of getting the disease. Researchers who study Ebola hemorrhagic fever viruses are also at risk of developing the disease if a laboratory accident occurs.