Research efforts to find a more effective Johne’s vaccine has now moved into Phase III, with five different vaccines being tested on goats at the University of Georgia.
The hope is to develop a more effective vaccine that prevents bacterial shedding, reduces injection site lesions and does not have cross reactivity with bovine tuberculosis tests.
Two years ago, the Johne’s Disease Integrated Program (JDIP) started a rigorous screening project of 22 mutant Johne’s strains. The first phase of the project was to test those mutants at the cellular level. Eight of the best testing strains were then tested in a mouse trial to see which showed the most promise.
Now five strains are being tested in 80 goat kids (including test groups and controls). Goats react similarly as cattle to Johne’s but are cheaper and provide faster results. “The goats have been vaccinated and exposed to Johne’s at this point,” says Ken Olson, JDIP outreach coordinator. “The goats will be sacrificed to determine Johne’s infection status, with about a year needed to collect all the data.”
It’s hoped that one or two of the mutant strains will prove to be superior for Johne’s protection. Those strains will then be offered for commercial development, which could take a further three to five years. But even that should be expedited, since of the preliminary screening work that has already been done, says Olson.
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