Recent approaches for control of E. coli and respiratory complex in Middle East

Area of Science:

• Veterinary Immunology
• Avian Pathology

Background:

• Concurrent infections with virulent Escherichia coli (E. coli) and infectious bronchitis virus (IBV) pose significant threats to broiler health.
• Avian Pathogenic E. coli (APEC) can exacerbate the severity of IBV infections.

Purpose of the Study:

• To evaluate the efficacy of Poulvac E. coli vaccine in mitigating clinical signs and complications from concurrent E. coli and IBV variant 02 challenges.
• To assess the vaccine's impact on broiler performance, mortality, and immune responses.

Main Methods:

• 100 one-day-old broiler chicks were used, with vaccination status as the primary variable.
• Birds were challenged with virulent E. coli O78 and IBV variant 02.
• Evaluations included clinical signs, mortality, post-mortem lesions, body weight, and serological responses.
• Re-isolation and RT-PCR were used to confirm IBV variant 02 presence.

Main Results:

• Poulvac E. coli vaccination improved body weight gain at 35 days in birds co-infected with E. coli and IBV variant 02.
• Mortality was reduced from 25% in unvaccinated birds to 10% in vaccinated birds challenged with both pathogens.
• IBV variant 02 challenge alone did not cause mortality, indicating APEC exacerbates IBV severity.
• The vaccine did not negatively impact immune responses to Infectious Bursal Disease (IBD) and improved responses to Newcastle Disease Virus (NDV), Avian Influenza (AI) H5, and IBV.

Conclusions:

• Poulvac E. coli vaccination is effective in reducing mortality and improving growth performance in broilers facing concurrent E. coli and IBV variant 02 infections.
• The vaccine demonstrates a beneficial effect on the overall immune status of broiler chickens, enhancing responses to other critical viral antigens.