Hemorrhagic Fever Viruses Examined As Potential Bioweapons

Ebola, Marburg, Lassa, and other viruses that cause deadly hemorrhagic fever illnesses could be used as biological weapons, according to a report from the Working Group on Civilian Biodefense, a panel of 26 experts convened by the Center for Civilian Biodefense Strategies at the Johns Hopkins Bloomberg School of Public Health. The group’s consensus statement, which appears in the May 8, 2002 issue of the Journal of the American Medical Association (JAMA), is based on an analysis of published research and offers public health and medical guidelines for managing a potential attack.

Like smallpox and anthrax, the Centers for Disease Control and Prevention (CDC) considers hemorrhagic fever viruses “category A” biological weapons agents, because they have the potential to cause widespread illness and death, and would require special public health preparedness measures to contain an outbreak. The Working Group’s report focuses on eight viruses: Ebola, Marburg, Lassa fever, New World Arenavirus, Rift Valley Fever, yellow fever, Ornsk hemorrhagic fever, and Kyasanur Forest Disease. Ebola and Marburg, which belong to the Filoviridae family of viruses, can be spread from person to person and are among the most deadly hemorrhagic fever illnesses. Ebola kills 50 to 90 percent of those infected, while Marburg is fatal 23 to 70 percent of the time.

“An outbreak of Ebola and Marburg would have a significant impact on our society, because they carry significant morbidity and mortality, and other than supportive medical care, there are no specific treatments,” explains lead author Luciana Borio, MD, fellow at the Johns Hopkins Center for Civilian Biodefense Strategies and the Critical Care Medicine Department of the National Institutes of Health. “It is not possible to predict whether any of the hemorrhagic fever viruses are likely to be used as a bioweapon. However, we know that it is not impossible to weaponize these viruses and we, in medicine and public health, are obliged to prepare.”

If an attack were to occur in the United States, the report notes that diagnosing hemorrhagic fever viruses may be difficult, since most clinicians are unfamiliar with these diseases. Most hemorrhagic fever illnesses begin with a fever and rash, which is similar to other more common illnesses. In addition, there are no widely available diagnostic tests. Currently, the CDC in Atlanta, Georgia and USAMRIID in Frederick, Maryland house the only facilities in the U.S. equipped to diagnose hemorrhagic fever viruses.

According to the Working Group, few effective therapies or vaccines are available to deal with hemorrhagic fever viruses. The antiviral drug ribavirin is recommended only for the treatment of the Arenaviridae and the Bunyaviridae families of viruses. For the Filoviridae (Ebola, Marburg) and the Flaviviridae, the researchers recommend providing supportive care to treat the symptoms of infected patients. There is a vaccine to prevent yellow fever, but it is not widely available and it would not be useful to provide protection after exposure.

The Working Group says strict infection controls must be used to prevent the spread of hemorrhagic fever viruses during an outbreak, many of which can be spread from person-to-person contact, and less commonly, via the airborne route. The report recommends clinicians wear special protective gear and that patients be isolated.

“The Working Group’s consensus recommends improvements to our diagnostic capacity and the development of a rapid test for diagnosing hemorrhagic fever viruses. Research efforts should also focus on new antiviral medications, vaccines, and a more fundamental scientific study of the viruses that cause hemorrhagic fever illness,” adds Dr. Borio.

“Hemorrhagic Fever Viruses as Biological Weapons, Medical and Public Health Management” was written by Luciana Borio, MD; Thomas V. Inglesby, MD; C.J. Peters, MD; Alan L. Schmaljohn, PhD; James M. Hughes, MD; Peter B. Jahrling, PhD; Thomas Ksiazek, DVM, PhD; Karl M. Johnson, MD; Andrea Meyerhoff, MD; Tara O’Toole, MD, MPH; Michael S. Ascher, MD; John Bartlett, MD; Joel G. Breman, MD, DTPH; Edward M. Eitzen, Jr., MD, MPH; Margaret Hamburg, MD; Jerry Hauer, MPH; D.A. Henderson, MD, MPH; Richard T. Johnson, MD, Gigi Kwik, PhD; Marci Layton, MD; Scott Lillibridge, MD; Gary J. Nabel, MD, PhD; Michael T. Osterholm, PhD, MPH; Trish M. Perl, MD, MSc; Philip Russell, MD; and Kevin Tonat, DrPH, MPH and appears in the May 8 edition of JAMA.

The participant’s institution or agency provided funding for the study.