LEAF/TERRA Professor Highlights the Global Impact of Avian Influenza and the Urgency of Preventive Measures

In recent days, reports have emerged regarding outbreaks of avian influenza in Portugal, with new cases detected in poultry farms and wild birds. This situation has raised concerns in both the poultry sector and public health, particularly regarding the urgent need to strengthen biosafety practices in the country. To date, there have been no reported human infections in Portugal, but health authorities such as the Directorate-General for Food and Veterinary Affairs (DGAV) and the Directorate-General of Health (DGS) are monitoring the situation and reinforcing control measures.

Economic Costs and Associated Risks

Professor Madalena Lordelo, a researcher at LEAF – Linking Landscape, Environment, Agriculture, and Food, and a member of the Associated Laboratory TERRA, is an expert in avian science and has been closely following the recent avian influenza outbreaks. Madalena Lordelo highlights the significant economic impacts of avian influenza outbreaks, including losses for producers, disruption of exports, and increased costs related to vaccines, treatments, and biosafety measures, affecting the entire supply chain. The detection of cases in Lisbon has already led to the prohibition of exporting chicken meat and eggs to Macau and Hong Kong. “Avian influenza can have serious economic consequences, especially in regions where the economy heavily depends on the poultry sector,” warns the Professor.

Madalena Lordelo stresses the complexity of the virus transmission, which can occur in multiple stages, from wild birds to domestic birds, and possibly to humans and other species:

• From bird to bird: Avian influenza is common among birds, particularly wild birds, where Influenza A viruses exist in the digestive system and are transmitted through feces, saliva, and secretions. Domestic birds, such as chickens, turkeys, and ducks, can become infected by sharing water or coming into contact with wild bird droppings, potentially mutating into highly pathogenic forms, such as H5N1;
• From birds to other species: The virus can infect mammals, as demonstrated by the transmission of H5N1 to dairy cows, highlighting its ability to cross species barriers;
• From birds to humans: Transmission occurs through direct contact with infected birds, secretions, or contaminated materials. This year, the first human case of H5N1 in the U.S. was recorded, resulting in death in a person with preexisting medical conditions and exposure to both wild and domestic birds;
• From human to human: This has not yet occurred, but it could happen if the virus undergoes mutations that allow efficient transmission between humans, potentially leading to pandemic outbreaks.

While the general risk to the population is low, individuals who work with birds or livestock have a higher exposure to the virus, the expert points out.

Effects on Different Production Systems

The LEAF/TERRA Professor also discusses the impact of avian influenza spread in different production systems, from intensive to organic and small-scale systems. In intensive systems, the high population density requires strict biosafety measures to contain the rapid spread of the virus. In extensive and organic systems, access to the outdoors increases the risk of contact with wild birds, natural reservoirs of the virus, limiting the effectiveness of control efforts. In small-scale farms with native breeds, despite the greater resistance to infection, these birds can act as reservoirs for the virus, perpetuating its circulation due to contact with wild birds. In the case of small-scale farms, the expert further emphasizes that “access to the outdoors, although beneficial in various contexts, may increase the susceptibility of domestic birds to the virus spread due to the higher risk of contact with wild birds carrying the virus.”

In this context, biosafety measures in poultry production systems play a crucial role in mitigating the spread of diseases, such as avian influenza, especially in intensive systems that use commercial high-production strains, which are less hardy than purebred species. According to Madalena Lordelo, “it is essential to invest in preventive biosafety measures, such as strict access control to poultry houses and investing in training programs for producers to significantly reduce the risks associated with disease spread.”

The Role of Science and Surveillance

With cases detected in several regions, including Lisbon, and the global impact of the disease, Professor Madalena Lordelo underscores the importance of an integrated approach to combat the outbreak. “Collaboration between producers, researchers, and policymakers will be essential to ensure the resilience of the poultry sector in the face of this challenge,” she states.

For Madalena Lordelo, the emergence of avian influenza highlights the interconnection between wildlife, domestic animals, and human health, emphasizing the importance of an integrative “One Health” approach.

The Associate Laboratory TERRA emphasizes the importance of epidemiological surveillance and scientific research as fundamental pillars in combating disease outbreaks. It is crucial to deepen the study of virus transmission dynamics to develop preventive strategies that avoid pandemic levels and minimize impacts on public health and the economy.

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