Mexico has reported an outbreak of highly pathogenic H5N1 bird flu on a farm in the Yucatan Peninsula, its first outbreak in poultry in more than two years, the World Organisation for Animal Health (WOAH) said on Friday.

The virus was detected in a flock of 225,860 laying hens in the town of Uman, the Paris-based WOAH said, citing a report from Mexican authorities. All of the birds were subsequently culled as a precaution.

The farm's own veterinarian raised the alarm after an unusual die-off of 862 birds, according to the Yucatan Daily News. Technicians from Senasica, Mexico's agricultural health and food safety agency, took samples under strict biosecurity rules, and laboratory tests confirmed H5N1.

Containment zone around the farm

Specialists have set a containment zone with a 10-kilometre radius around the farm, which is under permanent quarantine. Every bird will be removed, contaminated feed and supplies destroyed, and the barns disinfected and left empty.

Before the farm can restock, officials will bring in sentinel birds to confirm the virus has gone. Teams are also sampling every commercial broiler, egg-laying and breeder farm inside the radius, and emergency vaccination at nearby farms may be approved depending on the results.

Officials say eggs remain safe

Federal agriculture officials said the outbreak will not affect supply and that chicken and eggs remain safe to eat. The farm held about 0.09% of Mexico's national flock, according to the agriculture ministry.

Yucatan has faced the virus before. In November 2022, H5N1 was confirmed at three egg operations in Uman and Timucuy, hitting more than 312,000 birds in the first wave. That outbreak went on to last seven months and left about 2.7 million chickens dead or culled.