Typically, samples of tissue, blood, feces, and serum are used for most diagnostic tests; however, in the last few years, oral fluids have been used to identify particular pathogens in pigs.
The Iowa State University Veterinary Diagnostic Laboratory (ISUVDL) has been using oral fluids from pigs to detect the swine flu virus, among other viruses, and to classify both North American and European strains. Positive results from oral fluids are used as an indicator that such pathogens are present in a group of pigs, rather than disease diagnosis. Sampling oral fluids have become a preferred method for detecting swine flu, as oral fluids are a more sensitive and economical approach over serum sampling, as well as a more animal-friendly system.
Swine influenza virus A (SIV) is widely present in pigs of all ages; but SIV shedding (the infectious period) can be brief, usually taking only 2-3 days. Rather than nasal swabs or tissues, oral fluids have become a better means of identifying pigs that are currently shedding SIV.
ISUVDL has found that idenfitying other viruses using oral fluids, such as porcine reproductive and respiratory syndrome (PRRS), can be better developed by:
1. Attention to details in collecting oral fluids to minimize amounts of feces or feed in the samples;
2. Immediate chilling of the oral fluid sample at collection and maintaining the “cold chain” through the entire submission process; and
3. Choosing samples with the highest concentration of virus for sequencing. Currently, data from the ISUVDL suggests that sequencing success from serum and oral fluids is fairly similar if starting concentration is similar.
Though these particulars have shown a higher success rate in detecting PRRS, they also help in the detection of SIV.
Such developments are very important: healthy animals lower the cost and safety of meat proteins for the ever-growing, -demanding and health-conscious human consumer.
Conceived, Developed and Written by Dr. Subodh Das and Tara Mahadevan
February 11, 2013
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