Thanks to Greg Folkers for sending the link to this report in Annals of Internal Medicine: Ebola Hemorrhagic Fever in 2014: The Tale of an Evolving EpidemicEbola. Excerpt:
The current outbreak, which began in December 2013 and is the largest ever, was first detected in March 2014 when cases were recognized in southern Guinea (4). Liberia, Sierra Leone, and Nigeria are now also involved in the epidemic. The challenge is unprecedented because these countries have some of the worst physician–patient ratios in West Africa (more than 86 000 patients per physician in Liberia and 45 000 patients per physician in Sierra Leone).
Through 1 August 2014, a total of 1603 suspected and confirmed cases (1009 of which are laboratory-confirmed) and 887 deaths have been reported for a mortality rate of approximately 55%. Because contemporary international travel affords the ability to board an airplane and be virtually anywhere in the world in less than 24 hours, there is substantial concern that the disease could spread beyond West Africa to such places as Europe and North America.
For this reason, on 31 July 2014, the Centers for Disease Control and Prevention issued a level 3 travel advisory urging all U.S. residents to avoid nonessential travel to the affected region (5).
The incubation period of Ebola is generally 1 to 2 weeks but can range from 2 to 21 days. Initial clinical symptoms are nonspecific, with sudden onset of fever, chills, myalgia, and malaise. This is followed by flu-like symptoms (nasal discharge, cough, and shortness of breath); gastrointestinal symptoms (diarrhea, nausea, vomiting, and abdominal pain); and, finally, hemorrhagic symptoms in the most severe cases.
Poor prognosis is associated with the development of shock, encephalopathy, and extensive hemorrhage. Laboratory findings include leukopenia, thrombocytopenia, elevated levels of aminotransferase and prothrombin, and partial thromboplastin times with presence of fibrin split products indicating diffuse intravascular coagulation (1).
The pathogenesis of the disease is not well-understood. Studies in nonhuman primates have shown that EBOV replicates in monocytes, macrophages, and dendritic cells (6); however, in situ hybridization and electron microscopy have also shown the presence of virus in endothelial cells, fibroblasts, hepatocytes, and adrenal cells. The virus disseminates to lymph nodes, the liver, and the spleen.
There is little inflammatory response and significant lymphocyte apoptosis, which leads to lymphopenia and seems to be a marker of prognosis. Inhibition of the type I interferon response seems to be important in the pathogenesis of Ebola. Dysregulation of the coagulation cascade and production of proinflammatory cytokines by macrophages leads to shock and multiorgan failure in the terminal phase (1).
Diagnosis of Ebola can be difficult initially because the symptoms can be confused with those of diseases that are more common in Equatorial Africa, such as malaria, typhoid fever, bacterial meningitis, or Lassa fever. When the diagnosis is suspected, reverse transcriptase polymerase chain reaction and antigen detection by enzyme-linked immunosorbent assay are the most useful tests. Unfortunately, these tests are only available in referral centers or national reference laboratories and have not been readily available in remote areas of Africa where most outbreaks have occurred (1).
Infection occurs through contact of infected body fluids with mucosal surfaces or skin or through parenteral injection. Thus, most cases occur in persons providing direct care to patients, such as family members or health care professionals. Traditional medical practices and funerals contribute to transmission to household members. Amplified transmission occurs in health care facilities, with approximately one quarter of cases occurring among health care workers.
The most important measure to control an outbreak is implementing strict barrier and droplet precautions. Personal protective equipment and sterile injection equipment are also important.
When a patient dies, the body should be handled with extreme caution. Incineration is recommended but is not a usual practice in Africa and is rarely available in the field.