Federal agriculture officials confirmed a case of highly pathogenic H5N1 bird flu at a commercial egg farm in Umán, just southwest of Mérida, and ordered the entire flock destroyed.
The farm held 225,860 laying hens. That is about 0.09% of Mexico’s national flock, according to the Secretaría de Agricultura y Desarrollo Rural, which announced the case Thursday. Officials said the outbreak will not affect supply and that chicken and eggs remain safe to eat.
The farm was not named in the government’s statement.
How the case was caught
The alarm came from the farm’s own veterinarian, who reported an unusual die-off of 862 birds. Technicians from Senasica, Mexico’s agricultural health and food safety agency, took samples under strict biosecurity rules.
A preliminary test at an official lab in Mérida came back positive for H5. Samples then went to a higher-security laboratory in Mexico City run by the Mexico-United States Commission for the Prevention of Foot-and-Mouth Disease and Other Exotic Animal Diseases. There, the virus was isolated and its genome sequenced.
Officials said the response was in motion in less than 24 hours.
A 10-kilometer ring
Specialists set a containment zone with a 10-kilometer (6.2-mile) radius around the farm. The farm itself 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 — test animals used to confirm the virus is gone. Teams are also sampling every commercial broiler, egg-laying and breeder farm inside the radius. Depending on those results, Senasica’s animal health office may approve emergency vaccination at nearby farms.
Investigators are checking ponds and other bodies of water near Umán’s industrial zone. Migratory birds from North America arrive in the region each winter, and wild birds are a common carrier of the virus. A wildlife epidemiology team is also heading to the state to sample free-living birds.
Yucatán has been here before
The state knows this virus well. In November 2022, H5N1 was confirmed at three egg operations in Umán and Timucuy, hitting more than 312,000 birds in the first wave. That 2022 outbreak went on to last seven months, reached 15 commercial farms and two backyard flocks, and left about 2.7 million chickens dead or culled.
At the time, Yucatán ranked as Mexico’s fifth-largest egg producer, turning out about 107,000 metric tons (118,000 U.S. tons) a year. Much of the state’s large-scale poultry industry sits in the municipalities that ring Mérida, Umán among them.
H5N1 mainly infects birds. Human cases are rare and are generally tied to close contact with sick animals, not to eating properly cooked poultry or eggs.
Agriculture officials said they are stepping up surveillance nationwide during the cold season. They urged farmers to tighten biosecurity at their gates and to report any suspected case right away.
Fast Facts
- What: Highly pathogenic H5N1 avian influenza
- Where: Commercial egg farm in Umán, Yucatán
- Birds on site: 225,860 laying hens
- First sign: 862 unexplained bird deaths
- Containment zone: 10 kilometers (6.2 miles)
- Food safety: Officials say eggs and chicken are safe to eat
- Report suspected cases: 800-751-2100
- WhatsApp: 55-3996-4462
- Email: [email protected]
With reporting from CorresponsalesMX, El Financiero and Diario de Yucatán