Insights and Control Strategies for Fowl Typhoid and Pullorum Disease in Latin American Poultry

Avian salmonellosis remains a critical challenge for the global poultry industry, particularly in regions where intensive production coexists with traditional farming. In this comprehensive review, authors Pablo A. Chacana and Horacio R. Terzolo explore the evolving landscape of Pullorum Disease and Fowl Typhoid, emphasizing new diagnostic and preventive approaches for these long-standing bacterial threats. This work, originating from the National Institute of Agricultural Technology (INTA) in Balcarce, Argentina, was published in the journal "Revisión sobre Pullorosis y Tifosis aviar. Nuevos enfoques para viejos conceptos".

The research highlights a significant geographical divide in the prevalence of these diseases. While industrial poultry farms in many developed nations have successfully eradicated Salmonella Gallinarum biovars pullorum and gallinarum, these pathogens remain endemic in commercial operations across Latin America, Asia, and Africa. For producers, this represents not only a biological threat but a substantial economic burden. Losses stem from high mortality rates—which can reach 100% in chicks during their first two weeks—as well as the costs associated with veterinary intervention, sanitation of infected facilities, and the removal of dead birds.

A primary focus for professionals and technical editors is the complexity of transmission and the role of environmental vectors. The study details how these bacteria spread through both horizontal and vertical pathways, with even a low percentage of infected eggs (around 3%) being sufficient to propagate the disease throughout an entire hatchery. Because the clinical signs of Pullorum Disease and Fowl Typhoid are often indistinguishable in young birds—characterized by depression, respiratory distress, and diarrhea—rigorous biotyping is essential for an accurate diagnosis and subsequent management decisions.

From a diagnostic perspective, the authors emphasize the shift toward molecular biology as a means to improve speed and accuracy. While traditional bacteriology and serology remain the "gold standard" for many laboratories, they typically require a minimum of three days for identification. This is particularly relevant for the rapid screening of breeder flocks to prevent vertical transmission.

The debate surrounding vaccination strategies is a key area of interest for academics and Key Opinion Leaders (KOLs). In Latin America, the live attenuated 9R strain is the most widely used tool for preventing Fowl Typhoid. However, the research points out a technical nuance: while 9R provides some cross-protection against Salmonella Enteritidis, it is often insufficient to stop the spread of paratyphoid infections.

For producers looking for practical, non-antibiotic alternatives, the study examines the concept of competitive exclusion. Because modern chicks are hatched in sterile environments, they lack the protective intestinal flora they would naturally acquire from a hen. This proactive approach is increasingly vital as the industry faces mounting pressure to reduce antibiotic use, which often leads to drug resistance and the creation of silent carriers.

Ultimately, the path to eradication lies in a multi-faceted management program that prioritizes the health of breeder flocks. The authors argue that since humans, rodents, and inanimate objects act as mechanical vectors, strict biosecurity—including dedicated clothing, vehicle disinfection, and isolation—is the only way to minimize the risk of re-entry. By combining continuous serological monitoring with these new diagnostic and probiotic tools, the poultry industry can move closer to eliminating these persistent pathogens from commercial production chains.

Given the increasing limitations on antibiotic treatments and the interference of vaccines with serological monitoring, do you believe the industry should prioritize mandatory competitive exclusion programs over traditional vaccination to achieve long-term eradication?