Innovative Strategies for the Control and Prevention of Newcastle Disease in Latin America

Newcastle Disease (ND), a highly contagious viral pathology affecting poultry, remains a critical challenge for the commercial industry in Latin America. In this technical report, Eliana Icochea D’Arrigo, of the Avian Pathology Laboratory at the Faculty of Veterinary Medicine, UNMSM (Universidad Nacional Mayor de San Marcos) in Lima, Peru, explores the virus's impact and the necessary measures to mitigate its effects. The study, "Newcastle Disease: Understanding the virus better to make the best decisions in control. Part II" (Enfermedad de Newcastle: Conociendo mejor al virus para tomar las mejores decisiones en el control. Parte II), was published in the aviNews América Latina, issue of December 2024 (available at avinews.com). The author analyzes the persistent circulation of the virus in the region, providing an in-depth epidemiological landscape that identifies specific genotypes threatening commercial flocks and evaluates the efficacy of modern preventive measures to reduce economic losses.

One of the most significant practical applications highlighted in this research is the definitive transition toward recombinant vector vaccines. Producers and technical managers face a constant battle with maternal antibodies, which often neutralize traditional live vaccines administered at day one. The study demonstrates that using a herpesvirus of turkeys (HVT) vector expressing the Newcastle fusion protein allows for successful vaccination in the hatchery, regardless of maternal immunity levels. This shift not only ensures early protection but also simplifies field management by reducing the need for multiple booster sprays that can cause post-vaccinal respiratory reactions.

From a technical perspective, the research emphasizes that protection must be measured beyond mere survival rates. While traditional programs may prevent clinical mortality, they often fail to halt viral shedding. The data presented underscores that modern recombinant technology significantly reduces the amount of virus excreted by challenged birds into the environment. For the producer, this translates to lower viral pressure on the farm and a decreased risk of lateral transmission between sheds, which is vital for maintaining high-density production areas.

For the academic community and key opinion leaders, the article raises a compelling debate regarding the "genotype mismatch" theory. There has been ongoing discussion about whether vaccines derived from Genotype II (the basis of most classic strains) are sufficiently effective against the Genotype VII viruses prevalent in many Latin American outbreaks. The findings suggest that while cross-protection exists, the depth of immunity—specifically the reduction in oronasal and cloacal shedding—is highly dependent on the vaccine's ability to induce a robust and sustained cellular immune response rather than just high antibody titers.

Furthermore, the study integrates the role of biosecurity as a non-negotiable pillar that complements vaccination. It details how environmental factors and management stress can undermine vaccine efficacy, leading to "vaccine failures" that are often incorrectly attributed to the biological product itself. By analyzing field cases, the authors illustrate how a holistic approach, combining high-tech hatchery vaccination with stringent biosecurity, creates a "bio-bubble" that protects the genetic potential of the birds and ensures the long-term profitability of the enterprise.

In conclusion, the research advocates for a standardized regional approach to monitoring and classification. By adopting the universal classification scheme proposed by leading researchers in the field, Latin American poultry systems can better track the evolution of the virus and adapt their immunological strategies in real-time. This proactive stance is essential for the region to maintain its competitive edge in the global poultry market and move toward a future of reduced Newcastle Disease prevalence.