The evolution of strains of the Infectious Bursal Disease (IBD) virus (Gumboro disease) has transformed a disease that was once easily identified by clinical signs into a silent challenge for modern poultry production. Today, the disease remains widespread on farms, but predominantly occurs in a sub-clinical form, compromising animal performance, the efficiency of health programs, and birds’ immune responses without producing the classic signs observed two decades ago.
The warning was issued by Marco Lopes, Global Poultry Director at Ceva Animal Health, during an interview with the agriNews studio at SIAVS 2026. According to the specialist, understanding this epidemiological change is the first step toward reviewing prevention programs and adopting more effective control strategies.
The Evolution of Strains Has Changed the Behavior of Gumboro Disease
For Marco Lopes, one of the main challenges today is overcoming the false perception that Gumboro disease is no longer a sanitary concern.
“The disease is present. It is very different from what we saw perhaps 15 or 20 years ago. Today, it manifests itself in a different way. People end up having the perception that it is no longer present, but that is not the reality,” he stated.
According to him, in much of Latin America, especially in Brazil, the A4B1 strain, known as the Brazilian strain, predominates. Unlike variants that caused high mortality in the past, this strain rarely produces obvious clinical manifestations, making it difficult to identify in the field.
Production Losses Replace the Former Clinical Signs
The absence of clinical signs does not mean the absence of an economic impact. Marco Lopes explains that sub-clinical Gumboro disease compromises important production indicators, such as feed conversion, flock performance, and mortality, even if the effects are relatively small.
“The producer becomes accustomed to that level of mortality and feed conversion and stops recognizing the contribution of Gumboro disease to these results,” he observed.
According to the specialist, precisely because these losses occur continuously and at relatively low levels, many production systems fail to identify the actual impact of the disease on productivity.
Health Monitoring Becomes Essential
Given this new epidemiological profile, Marco Lopes emphasizes that monitoring has become a central component of disease control. Careful evaluation of the bursa of Fabricius during necropsy, combined with knowledge of the expected behavior of each vaccination program, should be accompanied by laboratory analyses to identify which strains are circulating and the intensity of the sanitary challenge.
In addition to the bursa, other lymphoid organs can also provide important information, depending on the variant involved. Therefore, according to him, integrating field assessments with laboratory diagnostics has become indispensable.
“The role of the technician and veterinarian is essential to raise suspicions in the field and associate this information with laboratory tests.”
Biosecurity Reduces Viral Pressure on Farms
Even with well-established vaccination programs, Marco Lopes emphasizes that biosecurity remains one of the pillars of Gumboro disease control. Since the virus remains resident on farms, rigorous cleaning and disinfection procedures, as well as adherence to downtime between flocks, significantly reduce the viral load present in the environment.
According to him, companies that shorten the downtime period frequently begin to observe an increase in cases precisely because they fail to properly carry out all the necessary sanitation procedures.
“Gumboro is a resident disease. Biosecurity is important for controlling the viral load present on the farm,” he emphasized.
In addition, the specialist points out that successful control depends on a combination of biosecurity, proper management, and vaccination programs that are compatible with the epidemiological reality of each company.
Early Protection Keeps Pace with the Evolution of the Sanitary Challenge
Epidemiological monitoring conducted by Ceva in different countries has shown that the challenges caused by current strains are occurring earlier in the birds’ lives. This change led to the development of NOVAMUNE®, a vaccine designed to bring protection to the bursa of Fabricius earlier and reduce the impact of circulating strains, particularly A4B1.
According to Marco Lopes, this earlier protection strengthens the birds’ immune foundation during the first stages of life, contributing not only to Gumboro disease control but also to a more effective response to other health challenges throughout the production cycle.
Understanding the Challenge Before Defining the Vaccination Strategy
At the end of the interview, Marco Lopes emphasized that there is no single strategy that applies to every company. Before defining any health program, it is essential to understand which strains are circulating within the production system and what objectives are expected from vaccination.
“Understand the challenge you are facing very well. By understanding what is circulating and what the vaccination program delivers, we can make much more assertive decisions for disease control,” he concluded.
In addition to developing solutions such as NOVAMUNE®, the Global Poultry Director highlighted that Ceva invests in monitoring, diagnostics, and technical support for customers to track the evolution of health challenges and continuously adjust control strategies.
More than simply supplying vaccines, he stated, the objective is to work in partnership with producers and technical teams so that biosecurity, monitoring, and vaccination programs evolve at the same pace as the epidemiological changes observed in the field.
Source: aviNews Brazil editorial team.