Tips from the Journals of the American Society for Microbiology
New Test May Allow for Rapid Detection of the Smallpox Virus
Researchers from Spain have developed a new test that may rapidly detect the variola virus, the etiological agent of smallpox, as well as differentiate it from other orthopoxviruses while avoiding false-negative results. Their findings appear in the December 2006 issue of the Journal of Clinical Microbiology.
Smallpox, one of the most serious and deadly diseases in the history of mankind, is attributed to the variola virus (VARV). Belonging to the orthopoxvirus genus, humans are the only know reservoir and despite its eradication in1980, smallpox is currently considered to pose major risk as a biological weapon.
In the study researchers used a specific probe to detect the variola virus and simultaneously differentiate it from other orthopoxviruses using a real-time genome amplification test based on TaqMan 3'-minor groove binder. A series of tests utilizing this method regularly detected 100 copies of variola virus DNA while avoiding false-negative results.
"The results obtained suggest that the assay is rapid, sensitive, specific, and suitable for the generic detection of orthopoxviruses and the identification of variola virus and avoids false-negative results in a single reaction tube.
(C.G. Fedele, A. Negredo, F. Molero, M.P. Sanchez-Seco, A. Tenorio. 2006. Use of internally controlled real-time genome amplification for detection of Variola virus and other Orthopoxviruses infecting humans. Journal of Clinical Microbiology, 44. 12: 4464-4470.)
Novel Peptide Targets Viral Cells and May Inhibit Influenza Virus Infection
Researchers from the University of Wisconsin have identified a novel antiviral peptide that may inhibit influenza viruses including the H5N1 strain. They report their findings in the December 2006 issue of the Journal of Virology.
Influenza A viruses are associated with approximately 31,000 annual deaths in the U.S. alone and currently pose a serious health threat throughout many parts of the world. Yearly vaccinations are the primary method of protection, however antiviral therapy plays an important role in treatment and transmission control. Although two classes of antiviral drugs are currently available, the H5NI strain has demonstrated resistance in recent testing.
In the study researchers tested the newly identified peptide, EB (entry blocker), for antiviral activity against influenza viruses including the H5N1 strain in mice. Results showed the peptide capable of inhibiting viral attachment to the cellular receptor ultimately preventing infection.
"This novel peptide has potential value as a reagent to study virus attachment and as a future therapeutic," say the researchers.
(J.C. Jones, E.A. Turpin, H. Bultmann, C.R. Brandt, S. Schultz-Cherry. 2006. Inhibition of influenza virus infection by a novel antiviral peptide that targets viral attachment to cells. Journal of Virology, 80. 24: 11960-11967.)
Microneedle Vaccination Technique Protects Rabbits Against Inhalation Anthrax Using Smaller Dosage
Microneedle-based vaccination with the current anthrax vaccine produced an equally effective immune response to intramuscular injection in rabbits using smaller dosage say researcher from Maryland and North Carolina. They report their findings in the December 2006 issue of the journal Infection and Immunity.
The anthrax attacks of September 2001, which killed 5 people and sickened many more, spurred an unprecedented level of support for the development of new treatment and prevention methods. Antibiotics have shown to be 100% effective at treating the cutaneous form of anthrax, however inhalation anthrax has a fatality rate of 75% or higher even with antibiotic treatment. The vaccine currently available is administered intramuscularly (i.m.), but recent studies suggest that intradermal (i.d.) delivery (in the skin) can increase the immune response while utilizing smaller doses, which is much more difficult to do with a conventional needle.
In the study researchers compared the efficacy of immunizing rabbits with the current anthrax vaccine intradermally using a microneedle and intramuscularly using a conventional needle. Results showed that intradermal delivery required less dosage to induce similar antibody levels as those seen following intramuscular injection. Rabbits that were administered the vaccine using the microneedle-based technique showed protection against inhalation anthrax at 100%, while those vaccinated using conventional methods were protected at 71%. Groups receiving lower dosages of the vaccine displayed partial protection regardless of vaccination technique.
"Our results suggest that i.d. delivery induces a level of protection against inhalation anthrax in a rabbit model that is comparable to that achieved via i.m. injection using conventional needle and syringe technology," say the researchers. "The use of minimally invasive, easy-to-use delivery devices such as the microneedle-based system described herein could potentially reduce the burden on highly skilled medical practitioners for biodefense vaccination.
(J.A. Mikszta, J.P. Dekker III, N.G. Harvey, C.H. Dean, J.M. Brittingham, J. Huang, V.J. Sullivan, B. Dyas, C.J. Roy, R.G. Ulrich. 2006. Microneedle-based intradermal delivery of the anthrax recombinant protective antigen vaccine. Infection and Immunity, 74. 12: 6806-6810.)
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