An effective Infectious Bronchitis control strategy for poultry
Infectious Bronchitis (IB) is a significant disease in the poultry industry for several technical economic reasons. IB, a highly contagious respiratory disease caused by a coronavirus, spreads rapidly through flocks via respiratory secretions, contaminated feed, water, and equipment causing severe economic losses and reducing the profitability of poultry farms.
IB can lead to long-term health issues in the flock, such as secondary bacterial Infections, which can have a severe impact at farm and further processing levels by increasing mortality and meat yield loss (e.g., increased condemnation rate due to airsacculitis, lack of carcass uniformity, etc.).
Some studies reveal that 1 bird can infect up to 20 birds. Thus, considering the high spread capability of this virus (IBV), effective IB management must consider good biosecurity practices, vaccination, and monitoring for early signs of the disease.
Since vaccination is a key point on the IB control, 3 pillars should be considered for a solid strategy. These are:
- Vaccination quality – Provide a homogeneous protection from day 1 for all the chicks in the flock (aiming at 100% of chicks).
- Disease control – Provide a broad-spectrum protection against several IBV strains.
- Disease prevention – Virus control by the reduction of shedding (lower R0, lower transmission).
When conducting spray vaccination at a hatchery, consider the following points to achieve the best vaccine efficacy against infectious diseases:
- Vaccine preparation: Ensure vaccines are stored properly at the correct temperature (2-8°C, typically in a refrigerator dedicated to vaccines) and follow the recommended and standardised procedures.
- Water quality: Use high-quality, non-chlorinated water with low mineral content to reconstitute the vaccine. Demineralised water is ideal.
- Spray equipment: Use appropriate spray equipment, with flat nozzles, to ensure even and consistent coverage.
- Spray droplet size: Ensure the spray produces coarse droplets (100-200 microns) to avoid deep inhalation into the respiratory tract, which can cause adverse reactions. The droplet size is the key aspect to define of vaccine virus multiplication area in respiratory system.
- Coverage and timing: Aim for even and complete coverage of the chicks.
- Monitoring: Regularly check to ensure that the spray equipment is functioning correctly and that the vaccine is uniformly applied. Use the Ceva Desvac Droplate tool in an empty chick box to verify coverage.
- Hygiene: Maintain strict hygiene standards to prevent contamination. Use dedicated equipment for vaccine preparation and application.
Disease control
Broad spectrum cross-protection is crucial for controlling IB in poultry, as in the field, multiple IBV clusters can impact simultaneously. The IB is caused by various strains of the coronavirus, which can mutate and recombine, leading to new variants. Broad spectrum cross-protection helps cover a wider range of these strains, reducing the risk of outbreaks.
Some vaccines can provide cross-protection against different IB strains. The combination of 2 different vaccines, such as IBird (1/96 strain – GI-13) and Massachusetts (GI-1) can provide protection against multiple serotypes and enhance the overall immunity of the flock.
Broad spectrum protection help maintain the integrity of the respiratory tract, reducing the occurrence of secondary bacterial infections, and allowing the expression of the full genetic potential of the chicks.
Disease prevention
IBV spreads rapidly to neighboring flocks and farms due to its rapid spread capacity. In this context, besides the disease clinical protection, blocking the field virus replication and shedding to the environment will be essential for IB control.
A scenario in which IB can reach Reproduction Rate R0 close to 20 means that each infected bird can infect another 20 birds. As a result, IB transmission is exponential. With a proper control by the vaccination programme, as the combination of IBird + Mass, the R0 will be greatly reduced.
As a result of controlling virus shedding, the spread of the virus will be reduced, and over time, this will lead to better control of Infectious Bronchitis.
