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\section{Introduction}  \emph{Francisella tularensis} is a Gram-negative bacterial pathogen capable of causing disease in a remarkably diverse array of hosts; at least 190 different species of mammals, 23 birds, 3 amphibians and 88 invertebrates are recognized as being susceptible to \emph{F. tularensis} infection \cite{9780470344880}. In addition, \textit{F. tularensis} utilizes a wide variety of environmental arthropod vectors for transmission \cite{24057273,21529386,20482589,18950590,22530023,21612530,20885922}. In experimental animals, \emph{F. tularensis} invades and replicates within both phagocytic and non-phagocytic cells \cite{24427743,23966861,21687806,23322778} and several studies have demonstrated that \emph{F. tularensis} survives engulfment by bacterivorous protists, often escaping from the food vacuole and replicating within the cytosol (\cite{12514047}Abd et al 2003; \cite{1501052,19820161}). \cite{12514047, 15010524,19820161}.  This ability to survive intracellularly is thought to contribute to the low infectious dose of \textit{F. tularensis}, which is fewer than 10 bacteria for the highly-virulent strains \cite{12364373}. Due to this high infectivity and an accompanying high rate of mortality and morbidity, \emph{F. tularensis} is of particular concern as an agent of biological terrorism and is therefore classified as a Tier 1 select agent by the US Centers for Disease Control \cite{11386933}. An attenuated live vaccine strain (LVS) was created from a virulent isolate in the 1950s \cite{833449}. LVS is not currently approved by the US Food and Drug Administration for standard human use because of safety and efficacy concerns. However, the LVS strain can be safely manipulated in biosafety level two laboratories (BSL2) and still causes rapid and severe disease in many hosts, allowing for \textit{F. tularensis} pathogenesis studies without the need for BSL3 containment.