New approaches to controlling infectious bronchitis in poultry

Infectious Bronchitis (IB) is a worldwide virus affecting poultry, notably due to its contagious nature. It is instigated by a gamma coronavirus, infecting the respiratory, urinary, and reproductive systems of chickens.

The virus strain’s tissue tropism determines the disorders it causes. The high mutation rate and recombination abilities of the Infectious Bronchitis Virus (IBV) exacerbate the issue. This is why there are many IBVs, not just one IB virus.

Evolution of numerous IBV strains globally

Efforts to characterize field isolates of IBV strains from broiler, layer, or breeder operations in various countries have enabled the creation of epidemiological maps. These maps depict the geographical distribution of the numerous IBV strains around the world.

By using highly sensitive molecular biology techniques, it’s possible to quickly detect IBV (via qRT-PCR: real-time reverse transcription polymerase chain reaction), assign it into genetic groups, and then characterize strains based on random changes in the genome. Real-time PCR shows limited possibility for genetic classification but, without sequencing, the identification of random changes is extremely limited with this method.

Many IBV strains are generated over time, but some of them disappear after a short period. Those that prevail tend to spread to other regions of the world. To protect susceptible poultry populations against the ever-changing IBV strains, it would be ideal to have homologous vaccines. However, most of these virus strains disappear, making it almost impossible to develop an IBV vaccine against each one.

Clinical signs of IBV in chickens

IBV manifests in different forms in chickens of varying ages. In chickens up to the age of 4 weeks, severe respiratory signs (sneezing, coughing, and rales) are the most common symptoms of IB. Diagnosing Infectious Bronchitis is challenging as respiratory system clinical signs are common in other poultry diseases. The morbidity rate may reach 100%.

For one-day-old chickens, an IB infection can permanently damage the oviduct, which affects egg production and egg quality during the production period. Layer hens infected with the IB virus may experience oophoritis and dystrophic necrobiotic lesions, primarily affecting the middle and final third of the oviduct’s mucosa lining. These can lead to a drop in egg production and an increase in the number of deformed and pigmentless eggs or eggs with soft shells and watery albumens.

How IBV is transmitted in chickens ?

Chickens affected by the disease are the primary source of infection, spreading the IBV via the aerogenous route, as well as through feed and water. Adult birds are also a major source of infection, acting as symptomless carriers that shed the virus in oronasal secretions and faeces.

New approaches to vaccination

Creating an effective vaccine has been an ongoing struggle in the battle against IBV. The primary challenge is keeping up with the virus’s rapid mutation rate. But there are new approaches to vaccination that show promise.

One of these methods is the use of autogenous vaccines, which are made from viruses isolated from a specific flock. This approach allows for a more targeted response to the specific IBV strain affecting a flock of chickens.

Another promising approach involves combining different IB viruses with various antigenic characteristics to obtain a synergistic effect. This can broaden the spectrum of protection. It has been demonstrated that combining antigenically different strains, such as those from the 793B group with a Mass type strain, acts synergistically to increase the protection spectrum of the two single vaccines if applied separately.

The role of health monitoring and vaccination services

In the fight against IBV, health monitoring and vaccination services are crucial. These services, such as the C.H.I.C.K® Program provide data and equipment for smart solutions like the Ceva Hatchery Connect®.

This technology allows for better monitoring of the health of poultry and can provide early detection of IBV. In addition, vaccination services ensure that vaccines are administered in a timely manner, which is crucial for preventing the spread of the virus.

Overall, the combat against IBV requires a multifaceted approach. By using improved health monitoring and vaccination services, alongside new methods of vaccine development, we can make strides in controlling this pervasive disease. Despite the challenges, with the continuous development and improvement of techniques and technology, there is hope for the future.

Understanding the immune response to IBV

Vaccination aims to stimulate an immune response in chickens, which enables their immune systems to recognize and fight off the IBV. As per studies listed on Google Scholar, the immune response is a critical factor in controlling IBV.

There are two types of immune responses: cell-mediated immunity (CMI) and humoral immunity.

CMI involves different types of cells in the immune system, such as T cells, which work together to destroy infected cells. On the other hand, humoral immunity involves B cells that produce antibodies to neutralize the virus. Both types of immune responses are essential for efficient protection against the IBV infection.

Once the virus invades the chicken’s body, the immune system is alerted, and the response is initiated. The B cells produce antibodies, particularly IgA and IgG, which neutralize the virus and prevent its replication. These antibodies can be found in the respiratory and urinary tracts, where the virus usually resides.

Controlling infectious bronchitis in poultry

Simultaneously, T cells destroy the infected cells, producing cytokines that help in controlling the virus. According to PubMed Crossref, live attenuated vaccines are most effective for stimulating CMI. But it’s crucial to maintain a balanced immune response. If the response is too strong, it could lead to tissue damage, further aggravating the disease.

Challenges and breakthroughs in vaccine development

The development of effective vaccines for IBV has been a significant challenge due to the high mutation and recombination rates of the virus, which leads to the emergence of numerous IBV strains. The high antigenic variability of the virus also contributes to the challenges in vaccine development, according to scholar Crossref.

However, breakthroughs have been made in recent years. Researchers are now focusing on creating vaccines that can provide broad protection against multiple strains of the virus. This is done by using live attenuated vaccines, which contain a live but weakened version of the virus.

According to a PubMed Crossref article, live attenuated vaccines have been successful in providing long-term protection against IBV. They stimulate both humoral and cell-mediated immune responses, providing an advantage over inactivated vaccines. They also trigger local immunity at the site of infection, further enhancing their effectiveness.

Despite the effectiveness of live attenuated vaccines, there are still risks associated with their use. For instance, they can revert to virulence, leading to outbreaks of the disease. Therefore, it’s important to continue researching and developing safer and more effective vaccines.

Future prospects in controlling IBV

The future of controlling IBV lies in the continuous development and improvement of techniques and technology. The integration of modern biotechnologies, such as genomics and proteomics, into vaccine development, could lead to more effective vaccines.

Moreover, new detection technologies can provide early and accurate identification of IBV. This is essential in preventing the spread of the virus and controlling outbreaks. In addition to these technological advancements, maintaining good farm biosecurity and hygiene practices is crucial in controlling the disease.

Furthermore, the role of health monitoring and vaccination services cannot be overstated. These services provide timely vaccination and valuable data for managing the disease. By combining these strategies with new vaccine development approaches, we are making strides in controlling IBV.

In conclusion, while IBV remains a significant challenge in poultry health, new approaches and advancements in technology and research are providing hope for the control and prevention of this pervasive disease.

It’s critical to stay updated on the latest research, such as those available on PMC Free and Avian Pathology Google, to leverage the most effective strategies in controlling IBV. The fight against IBV is multifaceted, and requires concerted efforts from researchers, poultry farmers, and vaccination service providers alike.