Laura Macció, Martín Masner

Executive Summary

This document explores the interaction between avian infectious bronchitis (IBV) and avian pathogenic Escherichia coli (APEC), highlighting how certain strains of IBV may predispose birds to severe secondary infections by APEC, resulting in aerosacculitis. This analysis aims to provide a detailed understanding of pathogenic dynamics and propose preventive measures to mitigate these risks in poultry production.

Introduction

Avian infectious bronchitis is a viral disease caused by the avian bronchitis coronavirus (IBV), primarily affecting the respiratory system of birds. Escherichia coli, on the other hand, is a bacterium that under certain pathogenic strains (APEC) can cause severe secondary infections such as aerosacculitis. This document analyzes how primary IBV infection can compromise the respiratory health of birds, facilitating the colonization and spread of APEC.

Relationship Between IBV and APEC

Respiratory Damage Induced by IBV

IBV affects the respiratory epithelium, decreasing local defenses and increasing susceptibility to secondary bacterial infections. Damage to the airways facilitates the adherence and proliferation of pathogenic bacteria like APEC.

Secondary Infections by APEC

APEC takes advantage of the deteriorated respiratory system to establish infections. These infections can progress to aerosacculitis, characterized by severe inflammation of the air sacs, significantly affecting the respiratory capacity and overall well-being of birds.

Strains of IBV and Their Implications

Various strains of IBV present different degrees of virulence and symptomatology, which can influence their ability to predispose birds to secondary infections by APEC. Some of the most relevant strains include:

G1-1 (Massachusetts Type): Common in vaccination programs, but capable of causing infections if there are failures in immunization or viral mutations.

G1-13 (Type 793B (4/91)): Associated with respiratory and renal problems.

G1-19 (Type QX): Strains associated with severe outbreaks of respiratory diseases and secondary complications, including renal or gastric.

G1-23 (Type Var-2): Associated with emerging outbreaks in recent years in Brazil, becoming the main lineage of field infections, associated with respiratory disease including aerosacculitis.

Prevention and Control Strategies

To mitigate the risk of aerosacculitis by APEC in poultry farms, it is essential to adopt an integrated approach that includes:

Epidemiological Surveillance: Continuous monitoring of prevalent IBV and APEC strains.

Effective Vaccination Programs: Implementation and regular review of vaccination programs to ensure coverage against predominant strains.

Biosecurity: Reinforcement of biosecurity measures to prevent the introduction and spread of pathogens.

Animal Management and Welfare: Improvements in the management of birds to strengthen their overall health and disease resistance.

Reflection on the Importance of Early Warning

The implementation of early warning systems to detect the risk of avian infectious bronchitis can have a significant impact on mitigating secondary infections by APEC. These systems allow for early interventions, reducing the severity of bronchitis and limiting opportunities for APEC to cause severe secondary infections. This not only improves the health and well-being of birds but also reduces the costs associated with treatment and production losses.

Economic Impact of Avian Infectious Bronchitis and APEC Infections

Global spending on vaccines for avian infectious bronchitis is estimated at hundreds of millions of dollars annually. APEC infections can reduce productive efficiency by 20-30% and outbreaks can decrease poultry exports from affected countries by 5-10%. In Brazil, the economic losses attributable to these diseases reached approximately $50 million USD in one year, mainly affecting small and medium-sized poultry enterprises.

Conclusion

The economic and health burden of avian infectious bronchitis and APEC infections is considerable, underscoring the need for effective management strategies and early warning systems. These diseases not only affect the economic viability of poultry farms but also impact the stability of regional and global food security.

Bibliographic References

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