Dong Li and colleagues at the Chinese Academy of Agricultural Sciences in Lanzhou have published a paper in Virology Journal investigating an alternative way to test the efficacy of FMD vaccines.

FMD is a serious disease of pigs around the world, they say, and vaccination prevention is still an important policy. OIE specifies 10,000 TCID₅₀(0.2 ml) of virulent virus for challenge test in pigs to test the potency of FMD vaccine by intradermal route inoculating the virus in the heel bulbs of one foot or by intramuscular route administering into one site of the neck behind the ear.

Convenience and speediness are available in the process of potency test of commercial FMD vaccine.

Li and co-workers selected the route of 'administering into one site of the muscular part of the neck behind the ear' because of convenience and speediness.

However, they found it difficult to infect control pigs even up to 100,000TCID₅₀ so they changed the challenged virus from cell-passaged strain to suckling mice-passaged one, measured its PID₅₀ (pigs median infected dose) and defined the virus challenge dose as 1000PID₅₀. They also increased the number of control pigs from two to three for easy evaluation.

Reference

Li D., Z-J. Lu, B.X. Xie, P. Sun, Y-L. Chen, Y-F. Fu and Z-X. Liu. 2010. Alternative way to test the efficacy of swine FMD vaccines: measurement of pigs median infected dose (PID50) and regulation of live virus challenge dose. Virology Journal, 7:215. doi:10.1186/1743-422X-7-215.

Further Reading

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You can view the full report (as a provisional PDF) by clicking here.

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Find out more information on foot and mouth disease (FMD) by clicking here.