Consistency, follow-up key to controlling IBV
Infectious bronchitis virus (IBV) is a “moving target” and trying to keep ahead of it requires consistency and follow-up, Sjaak de Wit, DVM, PhD, of GD Animal Health, the Netherlands, told Poultry Health Today.
While all strains of the virus can cause respiratory signs, many strains also cause kidney or gut problems in broilers as well as drops in egg production in breeders, de Wit explained.
Vaccines are critical for control, but much of the vaccinal virus can be lost when vaccines are not properly administered.
There is no one perfect vaccination solution, de Wit said, but a good place to start is the hatchery. If producers opt to use two IBV vaccines, hatchery vaccination should be followed with a field boost at 2 weeks of age. Giving a second vaccine earlier or later than 14 days of age will usually not be as effective.
Obtain a baseline
A chicken needs to have a certain amount of vaccine to induce a strong level of protection. Because IBV vaccines are applied by mass application via spray or drinking water — which is fast and easy — it’s impossible to tell if all birds get enough of the vaccine at the time of administration.
Therefore, checking on vaccination results is critical. A polymerase chain reaction (PCR) test should be performed several days after vaccine application to check on vaccine take, he said, and noted that PCR can also determine the different strains of IBV affecting a flock.
De Wit advised producers to first obtain baseline IBV titers with serology at processing so they can see if titers in subsequent flocks are going up or down. This helps determine how well the vaccination program is working.
Although PCR should be done soon after vaccination, it’s most effective when the virus is replicating. PCR also needs to be performed during the acute phase of a problem, when the birds are showing signs of respiratory or kidney problems or when there are drops in egg production, he commented.
De Wit strongly recommended checking for other infections, such as Mycoplasma or avian influenza, along with IBV. If other infectious disease problems are ignored and go unchecked, even the best IBV vaccination program won’t help. Without looking at the flock’s overall health status, producers can overestimate the relevance of IBV.
Even though IBV mutates often, it can be controlled if producers use the industry’s knowledge of the disease, he said.