ARS | Publication request: Improvements in avian influenza virus (AIV) specimen collection, transport and processing

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: January 3, 2012
Publication Date: April 2, 2012
Citation: Spackman, E., Mckinley, E.T. 2012. Improvements in avian influenza virus (AIV) specimen collection, transport and processing [abstract]. 8th International Symposium on Avian Influenza. p.32.

Technical Abstract: Specimen collection and transport are critical to achieving optimal sensitivity and specificity of diagnostic tests. Since influenza tests are so widely used, small improvements in sensitivity and specificity can translate into substantial cost savings from better test accuracy. To optimize testing for avian influenza virus (AIV) we have evaluated several aspects of sample collection and transport. First, advances in the manufacture of swabs has improved their capture and release properties. Using virus isolation, real-time reverse-transcription-polymerase chain reaction (rRT-PCR), and commercial antigen detection assays, we compared the performance of urethane foam and nylon flocked swabs with the standard Dacron swabs which are widely used for AIV sample collection. Initial results suggest that flocked swabs are superior to standard swabs for AIV detection from experimentally infected chickens. Other condition we are evaluating are: different transport conditions (wet versus dry), the effect of different media on detection by rRT-PCR, and whether up to 11 swabs can be pooled without affecting AIV detection. In addition to collection and transport conditions we have looked at the value of pre-enriching samples for rRT-PCR by incubating samples in eggs for 24, 48, 72 or 96 hours. Ten isolates from different avian species that were expected to have varying degrees of adaptation to eggs were used. In most cases 24 hours was sufficient to increase the sensitivity of rRT-PCR by 10-100 50% egg infectious doses for isolates which replicated well in chicken eggs. However, if isolates were not egg adapted pre-enrichment did not substantially improve sensitivity.