Mexico slaughters 1.2 million chickens infected with bird flu

(CNN) -- Mexican authorities say they've slaughtered more than a million chickens infected with bird flu.

Investigators detected the virus in 18 farms in the central Mexican state of Guanajuato, Mexico's Agriculture Ministry said this week.

Chickens there were infected with the H7N3 virus, which Mexican authorities said does not pose a threat to humans.

"This virus is exclusive to birds, so there is no risk for public safety," the Agriculture Ministry said earlier this month.

Authorities offered different tallies of how many infected birds had been slaughtered.

Agriculture Minister Enrique Martinez said Monday that more than 2.1 million chickens had been killed -- including 519,000 egg-producing chickens, 722,265 breeding chickens and 900,000 chickens raised for meat.

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