Journal of bioterrorism & biodefense最新文献

Select agent research in the United States must meet federally-mandated biological surety guidelines and rules which are comprised of two main components: biosecurity and biosafety. Biosecurity is the process employed for ensuring biological agents are properly safeguarded against theft, loss, diversion, unauthorized access or use/release. Biosafety is those processes that ensure that operations with such agents are conducted in a safe, secure and reliable manner. As such, a biological surety program is generally concerned with biological agents that present high risk for adverse medical and/or agricultural consequences upon release outside of proper containment. The U.S. Regional and National Biocontainment Laboratories (RBL, NBL) represent expertise in this type of research, and are actively engaged in the development of programs to address these critical needs and federal requirements. While this comprises an ongoing activity for the RBLs, NBLs and other facilities that handle select agents as new guidelines and regulations are implemented, the present article is written with the goal of presenting a simplified yet comprehensive review of these requirements. Herein, we discuss the requirements and the various activities that the RBL/NBL programs have implemented to achieve these metrics set forth by various agencies within the U.S. Federal government.

The identification of flavin-dependent thymidylate synthase (FDTS) as an essential enzyme and its occurrence in several pathogenic microbes opens opportunities for using FDTS enzyme as an excellent target for new antimicrobial drug discovery. In contrast to the human thymidylate synthase enzyme that utilizes methylene-tetrahydrofolate (CH₂H₄ folate) for the conversion of dUMP to dTMP, the microbial enzymes utilize an additional non-covalently bound FAD molecule for the hydride transfer from NAD(P)H. The structural and mechanistic differences between the human and microbial enzymes present an attractive opportunity for the design of antimicrobial compounds specific for the pathogens. We have determined the crystal structure of FDTS enzyme in complex with the methyl donor, CH₂H₄ folate. We describe here the structure of a FDTS mutant and compare it with other FDTS complex structures, including a FDTS-CH₂H₄ folate complex. We identified a conformational change essential for substrate binding and propose a strategy for the design of FDTS specific inhibitors.

Countermeasures that will effectively prevent or diminish the impact of a biological attack will depend on the rapid and accurate generation and analysis of genomic information. Because of their increasing level of sensitivity, rapidly decreasing cost, and their ability to effectively interrogate the genomes of previously unknown organisms, Next Generation Sequencing (NGS) technologies are revolutionizing the biological sciences. However, the exponential accumulation microbial data is equally outpacing the computational performance of existing analytical tools in their ability to translate DNA information into reliable detection, prophylactic and therapeutic countermeasures. It is now evident that the bottleneck for next-generation sequence data analysis will not be solved simply by scaling up our computational resources, but rather accomplished by implementing novel biodefense-oriented algorithms that overcome exiting vulnerabilities of speed, sensitivity and accuracy. Considering these circumstances, this document highlights the challenges and opportunities that biodefense stakeholders must consider in order to exploit more efficiently genomic information and translate this data into integrated countermeasures. The document overviews different genome analysis methods and explains concepts of DNA fingerprints, motif fingerprints, genomic barcodes and genomic signatures. A series of recommendations to promote genomics and bioinformatics as an effective form of deterrence and a valuable scientific platform for rapid technological insertion of detection, prophylactic, therapeutic countermeasures are discussed.

Zaire Ebola virus (ZEBOV) is a pathogen that causes severe hemorrhagic fever in humans and non-human primates. There are currently no licensed vaccines or approved treatments available against ZEBOV infections. The goal of this work was to evaluate different treatment strategies in conjunction with a replication deficient, recombinant human adenovirus serotype 5-based vaccine expressing the Zaire Ebola virus glycoprotein (Ad-CAGoptZGP) in Ebola infected mice and guinea pigs.Guinea pigs were treated with Ad-CAGoptZGP in combination with different treatment strategies after challenge with guinea pig adapted-ZEBOV (GA-ZEBOV). B10.BR mice were used to further characterize efficacy and immune responses following co-administration of Ad-CAGoptZGP with the most effective treatment: AdHu5 expressing recombinant IFN-α (hereafter termed DEF201) after challenge with a lethal dose of mouse adapted-ZEBOV (MA-ZEBOV).In mice, DEF201 treatment was able to elicit full protection against a lethal dose of MA-ZEBOV when administered 30 minutes after infection. In guinea pigs the Ad-CAGoptZGP and DEF201 combination therapy elicited full protection when treated 30 minutes post-exposure and were a superior treatment to Ad-CAGoptZGP supplemented with recombinant IFN-α protein. Further analysis of the immune response revealed that addition of DEF201 to Ad-CAGoptZGP enhances the resulting adaptive immune response against ZGP. The results highlight the importance of the innate immune response in the prevention of ZEBOV pathogenesis and support further development of the Ad-CAGoptZGP with DEF201 treatment combination for post-exposure therapy against ZEBOV infection.

Ebola and Marburg viruses are emerging/re-emerging zoonotic pathogens that cause severe viral hemorrhagic fever with case-fatality rates up to 90% in humans. Over the last three decades numerous outbreaks, of increasing frequency, have been documented in endemic regions. Furthermore, as a result of increased international travel filovirus infections have been imported into South Africa, Europe and North America. Both viruses possess the potential of being used as bioterrorism agents and are classified as category A pathogens. Currently there is neither a licensed vaccine nor effective treatment available, despite substantial efforts being d́edicated to understanding filovirus well as vaccine and drug development. One of the most promising vaccine platforms is based on replication competent recombinant vesicular stomatitis viruses (rVSV) that express a filovirus glycoprotein as the surface antigen. These rVSVs have been extensively studied in rodent and nonhuman primate models of filovirus disease and, in general, have been shown to be 100% protective in pre-exposure prophylaxis. In addition, rVSVs have demonstrated potential for post-exposure treatment, and thus would be particularly useful in the event of intentional release as well as accidental exposures in outbreak and laboratory settings.

Japanese encephalitis (JE) is a significant human health concern in Asia, Indonesia and parts of Australia with more than 3 billion people potentially at risk of infection with Japanese encephalitis virus (JEV), the causative agent of JE. Given the risk to human health and the theoretical potential for JEV use as a bioweapon, the development of safe and effective vaccines to prevent JEV infection is vital for preserving human health. The development of vaccines for JE began in the 1940s with formalin-inactivated mouse brain-derived vaccines. These vaccines have been shown to induce a protective immune response and to be very effective. Mouse brain-derived vaccines were still in use until May 2011 when the last lots of the BIKEN(®) JE-VAX(®) expired. Development of modern JE vaccines utilizes cell culture-derived viruses and improvements in manufacturing processes as well as removal of potential allergens or toxins have significantly improved vaccine safety. China has developed a live-attenuated vaccine that has proven to induce protective immunity following a single inoculation. In addition, a chimeric vaccine virus incorporating the prM and E structural proteins derived from the live-attenuated JE vaccine into the live-attenuated yellow fever 17D vaccine virus backbone is currently in clinical trials. In this article, we provide a summary of JE vaccine development and on-going clinical trials. We also discuss the potential risk of JEV as a bioweapon with a focus on virus sustainability if used as a weapon.

Tick-borne encephalitis (TBE) is a disease that is found from western Europe across Asia and into Japan. In recent years the incidence rate has been increasing as has the endemic range of the virus. Tick-borne encephalitis is caused by three genetically distinct sutypes of viruses within a single TBE virus (TBEV) serocomplex. These three subtypes consist of Far-eastern subtype TBEV (TBEV-FE), Siberian subtype (TBEV-Sib) and European subtype (TBEV-Eu). Each of these subtypes cause clinically distinct diseases with varying degrees of severity. Development of the first vaccines for TBEV began in the late 1930s shortly after the first isolation of TBEV-FE in Russia. In the 1970s Austria began large scale vaccine production and a nationalized vaccine campaign that significantly reduced the incidence rate of TBE. Currently there are four licensed TBE vaccines, two in Europe and two in Russia. These vaccines are all quite similar formalin-inactivated virus vaccines but the each use a different virus strain for production. Published studies have shown that European vaccines are cross-protective in rodent studies and elicit cross-reactive neutralizing antibody responses in human vaccines. European vaccines have been licensed for a rapid vaccine schedule that could be used in response to a significant outbreak and reasonable neutralizing antibody titers can be achieved after a single dose although a second dose provides nearly complete and long-lasting protection. This review focuses on the current status of licensed TBE vaccines and provides a brief summary of technology currently being developed for new vaccines.