Farmscape for August 24, 2022
The Swine Health Information Center has completed an evaluation of two types of pen-side tests for African Swine Fever.
Research conducted in Vietnam by the Swine Health Information Center has evaluated three pen-side tests for African Swine Fever virus detection, a pen-side PCR test and two lateral flow tests.
Dr. Paul Sundberg, the Executive Director of the Swine Health Information Center and a member of the Swine Innovation Porc Coordinated African Swine Fever Research Working Group, both types of tests were evaluated using whole blood and oral swabs.
Clip-Dr. Paul Sundberg-Swine Health Information Center:
The pen-side PCR test was actually pretty good at detecting ASF.
It was able to detect ASF in infected pigs within three days after they were infected and then detecting them as positive as long as ten days later and we stopped the project at 10 days post infection.
The pen-side PCR test was able to detect that infection early, it detected it all the way through and it was 100 percent specific.
We analysed whether there was an opportunity for false positives and that was the specific test and we also analysed if there was an opportunity for false negatives and that's testing its sensitivity.
Both of those were very good with the pen-side PCR test.
The specificity of the lateral flow was also very good but its sensitivity was very low.
It didn't detect ASF antigen in those samples as quickly in those samples as the PCR test did and it also didn't test positive as long.
It was very specific but it wasn't very sensitive in that it missed infections early and it missed infections late.
Dr. Sundberg says the ability of the lateral flow test to find infection throughout the course of infection was only about 50 percent at best and that's fairly low when you want to have confidence in a pen-side test.
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