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PUBLIC RELEASE DATE:
26-Apr-2007

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Contact: Carrie Patterson
cpatterson@asmusa.org
American Society for Microbiology
@ASMnewsroom

Tips from the Journals of the American Society for Microbiology

Copper Surfaces May Inhibit Influenza A Transmission

Researchers have determined that copper surfaces are significantly better than stainless steel at protecting against influenza A exposure. They report their findings in the April 2007 issue of the journal Applied and Environmental Microbiology.

Influenza A is a viral pathogen responsible for high mortality rates worldwide. The virus is easily transferred and can survive on a range of environmental surfaces. Previous studies have confirmed antimicrobial properties in copper against pathogenic bacteria, but antiviral activity has yet to be tested.

In the study influenza A particles were exposed to copper and stainless steel surfaces and incubated at 71.6 degrees Fahrenheit and 50 to 60% relative humidity. After 6 hours of exposure to copper only 500 virus particles were active, while 500,000 remained viable after 24 hours of incubation on stainless steel.

"The current study shows that copper surfaces may contribute to the number of control barriers able to reduce transmission of the virus, particularly in facilities, such as schools and health care units, where viral contamination has the ability to cause serious infection," say the researchers.

(J.O. Noyce, H. Michels, C.W. Keevil. 2007. Inactivation of influenza A virus on copper versus stainless steel surfaces. Applied and Environmental Microbiology, 73. 8: 2748-2750).


Chronic Wasting Disease Transmissible Among Rodents

For the first time, a new study demonstrates that certain rodents can be directly infected with CWD and therefore serve as animal models for further study of the disease. The researchers report their findings in the April 2007 issue of the Journal of Virology.

Chronic wasting disease (CWD), also known as mad cow disease in cattle and Creutzfeldt-Jacob disease in humans, is a transmissible prion disease most commonly found in deer and elk. Conversion of the normal host protein to an abnormal disease-associated form is an important part in the tracking of prion diseases and researchers are hopeful that rodent-adapted CWD models could assist in therapeutic development.

In the study transgenic and wild-type mice in addition to Syrian, Djungarian, Chinese, Siberian and Armenian hamsters were inoculated with CWD samples retrieved from deer and elk and monitored over various amounts of time. Distinct neuropathological patterns throughout differing incubation periods were observed in Chinese hamsters and transgenic mice offering the highest susceptibility rates. Wild-type mice and Djungarian hamsters were found not to be susceptible to CWD.

"We have shown that CWD from one or more cervid species can be transmitted to Sg, Chinese, Siberian, and Armenian hamsters and to Tg mice that express Sg hamster prion protein," say the researchers. "The resulting rodent-adapted CWD models could be useful in comparative studies of TSE strains in vivo as well as for testing potential anti-TSE therapeutic agents."

(G.J. Raymond, L.D. Raymond, K.D. Meade-White, A.G. Hughson, C. Favara, D. Gardner, E.S. Williams, M.W. Miller, R.E. Race, B. Caughey. 2007. Transmission and adaptation of chronic wasting disease to hamsters and transgenic mice: evidence for strains. Journal of Virology, 81. 8: 4305-4314).


Oral Vaccine Containing Salmonella May Protect Against Aerosolized Anthrax

Researchers from the U.S. and abroad have developed an orally administered Salmonella-based vaccine that protects mice against aerosolized anthrax and may also have human implications. They report their findings in the April 2007 issue of the journal Infection and Immunity.

Anthrax is a deadly disease that affects wildlife, livestock and humans and presents a serious threat as a potential biological weapon. Currently, there is a vaccine licensed for use in the US and the United Kingdom, and although effective, it requires multiple injections over several months, is expensive to produce and is only available to military personnel. A safe, effective and long-lasting vaccine available to civilians is necessary to protect mass populations in the event of an attack.

In the study researchers produced Salmonella enterica serovar Typhimurium expressing differing levels of the necessary protective antigen to induce anthrax immunity and orally immunized groups of mice. Following immunization the mice were then challenged with aerosolized anthrax spores. Five of the six mice that received the vaccine containing full expression of the antigen were protected against infection, while the vaccine with reduced antigen levels only provided up to 25 % protection.

"In the present study, we have shown for the first time that orally administered Salmonella expressing PA is able to protect mice against infection caused by airborne B. anthracis," say the researchers.

(M.G.M. Stokes, R.W. Titball, B.N. Neeson, J.E. Galen, N.J. Walker, A.J. Stagg, D.C. Jenner, J.E. Thwaite, J.P. Nataro, L.W.J. Baillie, H.S. Atkins. 2007. Oral administration of a Salmonella enterica-based vaccine expressing Bacillus anthracis protective antigen confers protection against aerosolized B. anthracis. Infection and Immunity, 75. 4: 1827-1834).

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