Avian flu is back to stay: "Spain is on the migratory routes. We can expect new cases every fall and winter."

After two years without cases, Spain is no longer a bird flu-free country . The epidemic has been spreading across our country for weeks, both among wild birds and on poultry farms, with no signs of slowing down so far.

To date, 12 outbreaks of highly pathogenic avian influenza (HPAI) caused by the H5N1 virus subtype have been detected on farms in Spain, and 47 have been identified in wild birds. This has led countries such as China to impose restrictions on the import of poultry products from Spain.

Spain, a country (still) little affected but vulnerable

It should be noted that, as Sylvain Compte, director of the Poultry Department at Ceva Animal Health, explained to 20minutos , despite the new outbreaks, "Spain remains among the least affected countries in Europe, along with France, both in terms of wild and domestic birds."

With the exception of the series of outbreaks recently detected in Valladolid, he continues, "no epidemiological relationship has been detected between the different outbreaks, and the most likely route of introduction into farms has been contact with wild birds."

Even so, this expert emphasizes that Spain is in a vulnerable position, as the migratory routes of numerous species of wild birds, considered the main reservoirs of the disease, pass through our country. Given this, he points out, "it is essential to strengthen protective measures , such as greater biosecurity and robust surveillance programs. Increased surveillance and early detection protocols, for both wild and domestic birds, help to quickly contain outbreaks."

Low risk for humans, although there are sporadic cases

On numerous occasions, authorities have reminded us that avian flu is a problem that primarily affects animal health , and that although there is a certain risk to humans, infections are rare and the probability of an epidemic remains very low.

Compte clarifies that "the risk of avian influenza to humans is primarily associated with direct contact with infected birds or contaminated environments. Although the overall risk to the population remains low, sporadic cases of transmission of the virus from animals to humans have been reported."

"The World Health Organization (WHO) continues to closely monitor the situation and recommends maintaining vigilance and strengthening global surveillance systems to detect the spread of avian influenza viruses as early as possible," it added.

In the last couple of years, alarm bells have sounded in the scientific community because, globally, avian flu has reached an unprecedented geographic spread and has been detected in an unprecedented number of different species , including many mammals. In fact, human cases have occurred in countries like the United States, some of them fatal.

In this regard, it should be noted that while the situation is worrying and organizations such as the WHO are calling for increased vigilance, the danger is limited to a series of viral variants with mutations that favor the jump to mammals, which have not yet been detected in Spain.

Economic, environmental and social consequences

Thus, the expert emphasizes that the main consequences of avian flu outbreaks with the characteristics of those detected in Spain do not have such a direct impact on human health. "We can summarize them into three types," he says. "Economic, environmental, and social."

"Economically," he explains, "the outbreaks cause significant losses for livestock producers and compensation costs for the governments of the affected countries."

Regarding the environmental consequences , Compte explains that "high mortality among wild birds alters ecosystems and the dynamics of scavenger species."

Finally, the spread of outbreaks can "affect rural livelihoods and food security , with cascading effects on supply chains."

Measures implemented

To date, the 12 outbreaks reported in Spain among poultry affect six provinces: Badajoz (one outbreak), Toledo (one outbreak), Huelva (two outbreaks), Guadalajara (one outbreak), Valladolid (six outbreaks), and Madrid (one outbreak). Containment measures have not been long in coming: as indicated by the Ministry of Agriculture, Fisheries, and Food , the protocol measures in these cases include the slaughter of affected birds, the imposition of quarantines, the reinforcement of biosecurity controls, and, in some cases, emergency vaccination, among others.

For example, the Madrid Regional Government has banned the raising of free-range chickens; the raising of ducks and geese with other poultry; the use of Anseriformes (an order of birds that includes ducks and geese) and Charadriiformes (an order that includes gulls) as hunting lures; the provision of water to poultry from reservoirs accessible to wild birds, unless it is adequately treated; and the presence of captive birds in animal concentration centers. It also requires strengthened biosecurity measures on poultry farms.

"Spanish veterinary authorities," Compte adds, "have increased awareness and preparedness for response due to previous outbreaks, which favors rapid containment and control efforts to prevent further spread of the virus."

Vaccination is an option in certain circumstances, but so far the situation in Spain has not required such campaigns. "Vaccination strategies have been included since 2022 as a complementary tool for the prevention and control of highly pathogenic avian influenza," says this expert. "However, given the currently low number of cases and Spain's recent experience, this option is not necessary for the time being."

In any case, neighboring countries have been implementing this type of action for some years. France has successfully implemented duck vaccination since October 2023 to limit the spread of the disease, especially in winter, and protect its poultry industry.

A problem with seasonal cycle

Ultimately, Compte emphasizes that "there are solutions available, such as vaccines, vaccination, and disease monitoring, as well as experience in implementing surveillance and vaccination if necessary."

Be that as it may, and despite all the measures being implemented, avian flu has become a permanent problem with global circulation. This is why this expert points out that "we can expect an increase in the number of cases every fall and winter, as migratory activity intensifies and adds to the existing risk posed by wild birds resident in Spain."

"Therefore," he concludes, "it is essential to maintain a strict focus on biosecurity, surveillance, and rapid control strategies."

References

Ministry of Agriculture, Fisheries and Food. Avian Influenza. Accessed online at https://www.mapa.gob.es/es/ganaderia/temas/sanidad-animal-higiene-ganadera/sanidad-animal/enfermedades/influenza-aviar/influenza_aviar on October 17, 2025.

Official Gazette of the Community of Madrid (2025). No. 247. Accessed online at https://bocm.es/bocm-20251016-22 on October 17, 2025.

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