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Phi 6 and Phi 8 as Potential Surrogates for Avian Influenza Viruses in Persistence Studies in Water-Abstract
ADCOCK, N., M. SIVAGANESAN, A. YU, J. D. BROWN, D. E. STALLKNECHT, AND E. W. RICE. Phi 6 and Phi 8 as Potential Surrogates for Avian Influenza Viruses in Persistence Studies in Water-Abstract . Presented at American Society for Microbiology 109th General Meeting, Philadelphia, PA, May 17 - 21, 2009.
To inform public
Wild aquatic birds are the natural reservoir for avian influenza viruses, and water is known to play an important role in the transmission of virus within this reservoir system. Despite its recognized importance, we have very little understanding of what factors enhance or limit the persistence of these viruses in water. Experimental work with these viruses is labor intensive and work with the highly pathogenic avian influenza (HPAI) strains is limited to laboratories with specialized biosafety and security capabilities. Information on the suitability of surrogates for these viruses would be valuable for studying their persistence in the aquatic environment. A published survival study for two Asian lineage H5N1 HPAI and eight low pathogenic avian influenza (LPAI) viruses was repeated using two lipid enveloped RNA bacteriophages, phi 6 and phi 8. Phage suspensions were diluted in sterile, buffered, distilled water (pH 7.4) at three salinities (0, 15, 30 ppt) and incubated at either 17°C or 28°C. Triplicate aliquots for each phage, salinity and temperature were removed weekly over a 180 day period and titer assays were determined by plaque assay using Pseudomonas syringae LM2489 as the host. The log reductions of the phage and virus titers over time were compared using covariance analysis. At 0 ppt salinity, phi 6 persisted at least as long as the two HPAI and seven of the eight LPAI viruses at 17°C and at 28°C. Phi 6 also persisted as long as both HPAI viruses at 15 and 30 ppt salinity at both temperatures with the exception of 17°C, 15 ppt where it inactivated more rapidly than one of the HPAI viruses. The persistence of phi 6 was similar to that of all but one of the LPAI viruses at 30 ppt, but the results were more varied at 15 ppt. For the most part, phi 8 did not persist as long as the HPAI and LPAI viruses. Based upon these results, the RNA bacteriophage phi 6 may have potential to serve as a useful surrogate for the H5N1 HPAI viruses for determination of persistence in fresh water, but not in brackish and salt water, at 17°C and 28°C.