Pathogenic rickettsiae as bioterrorism agents

Abstract

The diseases caused by rickettsiae vary from mild to severe clinical presentations, with case fatality ranging from none to over 30%. The severity of rickettsial diseases has been associated with age, delayed diagnosis, hepatic and renal dysfunction, central nervous system abnormalities, and pulmonary compromise. Despite the variability in clinical presentations many pathogenic rickettsiae cause debilitating diseases, any one of which could be used as a potential biological weapon. While Rickettsia prowazekii, R. rickettsii, and Coxiella burnetii pose serious problems and are currently considered bioterrorism agents, several other species could cause havoc once intentionally released into human populations. The complicating factors include misdiagnosis due to the similarity of rickettsial-induced clinical signs to many commonly occurring infections and subsequent delayed treatment. Vigilance, preparedness, and the availability of efficacious vaccines and antibiotics are required to avert the morbidity and mortality and disturbances generated by the intentional release of pathogenic rickettsiae into large and immunologically naive human populations. This presentation reviews the rickettsial attributes that make them potential bioterrorism agents, as well as issues related to signs that would alert the responsible authorities, and the preventive measures that could reduce impact of these agents.