IB could best be described as the “eye of the storm,” says Guillermo Zavala, DVM, PhD, a poultry health and production consultant for Avian Health International.

IB is caused by an RNA virus, which tends to mutate quickly. Vaccines developed to combat these viruses work well — until variant viruses emerge and the vaccines may or may not be effective. That’s why the poultry industry is always trying to play catch up with IB, he told Poultry Health Today.

Once the birds contract an IB virus, it becomes easy for dust particles and bacteria to penetrate deep into the tissues of the respiratory tract. Birds are then predisposed to secondary bacterial infections such as Escherichia coli. It’s the complications that occur with bacterial infections secondary to IB that can become so economically devastating, Zavala said.

Healthy environment is key

Providing a healthy environment for birds is key to reducing the incidence of IB. That means good air quality and good litter quality. If those things are in place, the consequences of an IB field challenge won’t be as serious, the veterinarian emphasized.

Biosecurity is also important for control of infectious diseases, but it alone can’t control viruses like IB, which can be easily transmitted via air, he noted.

When there’s an outbreak of IB producers can’t control, continuous sampling becomes necessary. The viruses need to be isolated, genetically characterized and compared to known viruses. Producers need to find out if the viruses are the same as before or different, and if they’ve changed, how widespread they’ve become, Zavala said. Once it’s demonstrated a widespread problem exists, then it’s time for the industry to think about developing a new vaccine or changing vaccination strategies, he said.