The recent Ebola virus disease (EVD) outbreak is the largest in our planet’s history. The epidemic is centered in West Africa, but isolated cases are being recognized across continents and represent a global health crisis1. The mortality rate, once infected in non-hospitalized patients, is near 70%2. Over 11,000 individuals have died in the recent outbreak, and this likely represents an underreported figure. In addition to the ever-rising death toll, children in West Africa are being orphaned at an alarming rate. With no proven vaccine or curative therapy currently available and the possibility for spread to tens of thousands of individuals or more, there is a desperate and urgent need for novel therapy to combat this deadly disease, yet clinical trials are just getting under way.
Clinical Features of Viral Hemorrhagic Fever (VHF)
Ebola virus infection, following an incubation period of 2 to 21 days, is clinically characterized initially by fever, myalgia, headache, weakness, and abdominal pain. This is frequently followed by vomiting, diarrhea, and occasionally by bruising and bleeding (about 1 in 5 infected); thus the terminology, Ebola hemorrhagic fever.
The hemorrhagic complications seen in Ebola virus infection are also described in other specific virus families by the US Centers for Disease Control, including arenaviruses, filoviruses, bunyaviruses, and flaviviruses; hence, the term viral hemorrhagic fever is used to describe the severe multiorgan dysfunction syndrome (MODS) in a substantial number of infected individuals3. VHF shares striking similarities with hemophagocytic syndromes (HPS), both familial hemophagocytic lymphohistiocytosis (HLH) and reactive hemophagocytic syndrome (rHPS, also called macrophage activation syndrome, or MAS), which include the following: prolonged fever, coagulopathy, hyperferritinemia, liver enzyme elevations, increased serum interleukin 1 (IL-1) levels, thrombocytopenia, and central nervous system (CNS) dysfunction4,5 (Table 1)6. Moreover, it has recently been elegantly shown in samples from the 2000–2001 …
Address correspondence to Dr. R.Q. Cron, Children’s of Alabama, Division of Pediatric Rheumatology, 1600 7th Ave. South, CPP #M210, Birmingham, Alabama 35233-1711, USA. E-mail: rcron{at}peds.uab.edu