News On Biodefense

Main Category: Bird Flu / Avian Flu
Also Included In: Flu / Cold / SARS;  Infectious Diseases / Bacteria / Viruses;  Bio-terrorism / Terrorism
Article Date: 25 Feb 2009 - 5:00 PDT

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The following news is based on presentations at the 2009 ASM Biodefense and Emerging Diseases Research Meeting, February 22-25 at the Baltimore Marriott Waterfront Hotel in Baltimore, Maryland.

IS OUR OBSESSION WITH PANDEMIC BIRD FLU JUSTIFIED?

While it is almost a certainty that within the next few decades humanity will experience another influenza pandemic, it may not be caused by the avian influenza strain H5N1 that many scientists believe could be a prime candidate.

"We continue to be aroused and some nearly panicked by the threat of a flu pandemic caused by the avian influenza virus, H5N1. Is this anxiety justified? In the more than 15 years since it was first recognized, this bird flu virus has yet cause very much mortality in humans or evolve to be readily transmitted between people," says Bruce Levin, the Samuel Candler Dobbs Professor of Biology at Emory University.

Nevertheless, because of the high case mortality of humans infected with H5N1 (sometimes exceeding 90%), pandemic influenza caused by this avian virus has appropriately stimulated a great deal of research on the microbiology, immunology, pathology, virulence, epidemiology and evolution of influenza. It has also contributed to a renaissance of interest in the great influenza of 1918, says Levin.

"The next pandemic could well have the potential to kill as many or more people than that in 1918, but we are far better prepared to deal with the next influenza pandemic than we were that of 1918," says Levin.

Unlike now, in 1918:

• It was not clear that a virus was responsible for the pandemic
  
  
• There were no vaccines or even ways to develop vaccines to prevent the disease
  
  
• There were no antiviral drugs to mitigate the course of this disease and reduce the rate of transmission
  
  
• There were no antibiotics to treat, or vaccines to prevent, secondary bacterial infections that evidence suggests were the major cause of mortality in influenza patients.

Plenary Session #6

NEW TECHNIQUE USES NANOPARTICLES TO QUICKLY IDENTIFY INFECTION AND PROPER TREATMENT

A new technique developed by University of Central Florida researchers can help quickly identify bacterial infections and determine the best antibiotic for treatment in a matter of hours instead of days.

Bacteria rapidly evolve mechanisms to become resistant to antibiotics. Therefore, identifying an effective antibiotic and administering it at a dosage that will successfully treat the infection is critical for healthcare decision making and vital in battle against antibiotic resistance.

Current methods for testing antibiotic susceptibility take a minimum of 24 hours to complete. Charalambos Kaittanis, Sudip Nath and J. Manuel Perez have developed a system using nanoparticles that successfully detected a bacterial strain in milk within 45 minutes and determined which antibiotics would work on it within 2 hours.

"Our nanoparticle-based method provided results faster without the need of sample purification and amplification," says Perez.

Poster Presentation #44

THE SCIENCE BEHIND THE "ANTHRAX LETTER" ATTACK INVESTIGATION

Scientists directly involved in the investigation of the anthrax letter attacks of 2001 will present their analyses and conclusions. Innovative science was a very important part of the investigation but has been widely misrepresented in the popular press because of secrecy requirements imposed by the FBI. This secrecy veil is now being lifted by allowing the investigative scientists to present their finds.

Paul Keim of Northern Arizona University will set the crime scene, the events, letters and the victims in the context of their work. Much of Dr. Keim's talk will be about the Ames strain, which was the type of B. anthracis found in the letters. This will include a global analysis of B. anthracis strains. Whole genome sequencing of the Ames genome led to the discovery of DNA polymorphisms that were unique to the Ames laboratory strain. Highly sensitive and specific assays were developed to identify the strain material. These were subjected to extensive validation to insure that the investigators knew their strengths and weaknesses.

Joe Michael from the Sandia National Lab in Albuquerque will be presenting spore analysis - in particular he will discuss the electromagnetic analysis for silicon in the spores. His analysis explains where the silicon is found within the letter spores and that its origin was probably part of the culture and growth process.

Jacques Ravel of University of Maryland School of Medicine/Institute for Genome Sciences, Baltimore, Maryland, will present the discovery of colony morphology mutants in the letter material and how these morphs were isolated and then whole genome sequenced. He and his team used comparative genomics to identify the genetic basis of the morphological differences. Finally, he will present their assay development, validation and implementation.

Tom Reynolds of Commonwealth Biotechnologies, Inc., Richmond, Virginia, will talk about his team's development of two assays to detect the genetic signatures associated with the morphological variants from the letters. This will include a description of the forensic analysis standards that were applied to the work. He will include results from his team's analysis of the evidentiary material.

Jason Bannan of the Federal Bureau of Investigation coordinated the scientific investigation of multiple laboratories and handled the evidence in the case. He will discuss integrating the science from multiple labs and how it tied the anthrax letters to a particular source flask. He will include a discussion of the federal legal standards for new scientific evidence and how the scientific teams were addressing this requirement.

Plenary Session #15

VACCINE PROTECTS AGAINST 1918 INFLUENZA STRAIN

Researchers have developed a vaccine that appears to protect against the 1918 "Spanish" influenza virus. Using a mammalian expression system they created a virus-like particle (VLP) that mimics the 1918 influenza virus, prompting the immune system to develop protective antibodies.

This is the first report describing the use of a 1918 VLP vaccine expressed and purified from mammalian cells. The results show that a non-replicating VLP is an effective influenza vaccine against the 1918 virus.

Scientists from the University of Pittsburgh and the Centers for Disease Control and Prevention administered the VLP vaccine to mice and ferrets, which were completely protected from a lethal challenge with the 1918 virus.

VLPs are small packages of artificially produced viral protein. They are assembled either spontaneously using high concentrations of viral protein, or by embedding the protein in a lipid membrane during protein synthesis. When encountered by an immune cell, a VLP looks like a real virus particle, because it is coated in viral protein (the antigen). However, because a VLP lacks DNA or RNA, it is not infectious.

VLP vaccines are made using cell expression systems. This genetic engineering approach, utilizing either mammalian cells or yeast, is often found in the production of vaccines. Cell culture systems are closely controlled, and can be scaled up relatively easily. In contrast, egg-based systems which provide the main source of current influenza vaccines rely on large supplies of fertilised chicken eggs for vaccine production, and are more difficult to control.

Poster Presentation #215

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Article adapted by Medical News Today from original press release.
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Source: Jim Sliwa
American Society for Microbiology