The bursa of Fabricius, also known as the cloacal bursa, is a unique central immune organ in poultry, playing a key role in developing the avian immune system. Lately, atypical bursal disease cases have been on the rise. When it hits, it means the vaccine didn’t work, or there’s a wild virus infection. Layer pullet farms see the highest infection rate at 47.53%, followed by white-feather broilers, 817 broilers, and yellow-feather broilers. The disease mostly strikes birds aged 30-45 days, though some cases are as early as 18 days.
Multiple IBDV strains are circulating in China, with nVarIBDV and vIBDV being the two main ones that are hurting the poultry industry.
Transmission of Bursal Disease and Advantages of Live Vaccines
IBDV in Chicken Farms
The bursal disease (IBDV) is tough to wipe out and can spread from one flock to another. New chicks in the same house could face an outbreak if a previous flock had variant or highly virulent IBDV strains. New variant strains also cause big problems like intestinal issues (e.g., gizzard erosion) and slow weight gain.
Maternal Antibodies
High maternal antibodies protect chicks from early IBDV infection. But as chicks get older, these antibodies fade and eventually disappear, making the flock more susceptible. During this time, reducing stress is critical to avoid triggering bursal damage.
Advantages of Live Vaccines
Live vaccines boost immunity to fight IBDV infection, quickly setting up protection to block wild virus infection. However, the “colonization” of IBD live vaccines hinges on timing, as maternal antibodies can interfere. Vaccinate too early, and maternal antibodies neutralize the vaccine; vaccinate too late, and the flock’s risk of wild virus infection rises. When picking a strain, it can’t be too strong to avoid harming the bursa or too weak to lack protection. WIXBIO IBD VACCINE LIVE provides a strong defense against both highly virulent and variant strains, with a solid ability to trigger immunity, fast, consistent antibody production, and fewer economic losses from subclinical IBDV infections and secondary Escherichia coli infections.
Harms Caused by IBDV
- Flock mortality or culling rates go up by about 0.5%.
- Recent pullet field data show the feed conversion ratio climbing from 2.3 to 2.32 or even 2.4.
- More frequent diseases or co-infections, like gizzard erosion, respiratory problems, airsacculitis, mycoplasma, Newcastle disease, and infectious bronchitis, drive up medication costs and cause significant productivity losses during the laying period.
How to Prevent Bursal Disease?
- Choose high-quality chicks and use an all-in, all-out system.
- For vaccines, choose a “live + inactivated” program. Early live vaccines quickly build protection to stop wild virus infection, while later + later inactivated vaccines boost circulating antibody levels. Follow WIX’s years of experience with IBD VACCINE LIVE for live vaccines using a two-dose strategy.
- Thoroughly disinfect the farm, poultry houses, personnel, vehicles, and equipment.
- Avoid cold stress, reduce stress from catching, transferring, or vaccinating birds, and manage environmental controls.
- Strengthen early chick vitality with products like Astragalus polysaccharide and vitamin C to boost immunity.
Precautions for Live Vaccine Use
Usage Notes:
- Before giving the vaccine through drinking water, flush the water lines to keep them clean.
- For drinking water immunization, add skim milk powder.
- Water deprivation: Stop water for 1 hour in summer and 2 hours in winter.
- Water volume calculation: Determine the water volume the flock can drink in 1-2 hours.
