VIDO-InterVac Developing Subunit Vaccine for Lawsonia Intracellularis

Researchers with VIDO-InterVac are developing a new subunit vaccine to protect pigs from Lawsonia intracellularis

by Bruce Cochrane – FarmScape Online

Lawsonia intracellularis, a bacteria found in about 90 percent of the world’s swine herds causes Ileitis, a swelling of the intestine in pigs.

Researchers with the Vaccine and Infectious Disease Organization are developing a subunit DIVA vaccine which will allow the differentiation of infected from vaccinated animals.
Dr. Heather Wilson, a research scientist with VIDO-InterVac, says a DIVA vaccine, especially a subunit vaccine offers a number of advantages over those that are currently available.

“We need to differentiate between infected versus vaccinated animals”

 

“There are two right now on the market but one of them is a live-attenuated vaccine, which means the bacteria is in a weakened state, so there is a small degree of worry that it might change and become more virulent and the other one is a killed vaccine. There is a little bit of hesitancy to administer that in some barns, not because they’re not effective. They are but you can’t tell if the animals have been infected or if they’ve been vaccinated.

“We call that DIVA.

“We need to differentiate between infected versus vaccinated animals. So what we’re doing is developing a subunit vaccine which means we’re just taking select proteins from Lawsonia and we’re paring that with some proteins that are absolutely are not related to Lawsonia and administering that in a vaccine so we can measure the antibody response against the Lawsonia and the non-Lawsonia components and if they’re both high then you know the animal has actually been vaccinated.

“You can actually back up the fact that the antibody titers are due to vaccination, not background infection.

Dr. Wilson says a subunit vaccine is safe. She says there is absolutely no way you can contract a disease from a subunit vaccine.

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