Medical Countermeasures for Filoviruses and Other Viral Agents

Abstract

Many viruses were considered historically and have been reconsidered recently as potential agents of great harm, through intentional release as weapons of biological warfare or bioterrorism. Two such lists, of which several circulate, are shown in Table 1. Another variation, a recent prioritization of concerns by the National Institute of Allergy and Infectious Disease (NIAID), is shown in Table 2. The discerning reader may note that regarding certain viral agents, different listings may appear wildly or illogically discordant. Conflicting perspectives will not be resolved herein: a consideration of the particular threat characteristics, diseases, vaccines, and treatments for even these truncated rosters of viral agents is well beyond the scope of this chapter. It suffices to note that priorities and concerns are drawn from imprecise and sometimes disputed information about these viruses in myriad areas, including the medical consequences of infection in terms of morbidity and mortality; the feasibility and ease of agent production; the minimal viral dose required to cause disease; the stability of the virus in storage and in aerosol form; the contagiousness or limited transmissibility of the virus via contacts of infected persons; the current availability of medical countermeasures; the ease by which individuals or groups may acquire the virus; and credible intelligence information indicating past or present weaponization. Variola virus, causative agent of smallpox, is considered separately in this volume. Here, emphasis is on the filoviruses Marburg virus (MARV) and Ebola virus (EBOV); these are among the most frightening of natural viral threat agents, not as contagious as variola virus, but more deadly, and uncontrolled by any currently available vaccine or therapy. Genetically engineered viruses are not considered here, nor are agents that have serious but solely indirect effects on humans through their impacts on agriculture or environment.