'Thousands' of Infections From 1 Poultry Hatchery
8-Year Salmonella Outbreak Traced to 1 Mail-Order Hatchery
May 30, 2012 -- A single mail-order poultry hatchery is responsible for an eight-year salmonella outbreak with 316 confirmed human cases in 43 states and thousands of likely infections.
Half of the cases were in children 5 years of age or younger.
The hatchery is identified only as "Hatchery C" in "the western United States" by CDC researcher Nicholas H. Gaffga, MD, MPH, and colleagues in their report in the New England Journal of Medicine. Previous CDC reports indicate that it's a large hatchery in New Mexico.
"During the 8-year period from 2004 through 2011, we identified 316 cases in 43 states as part of the outbreak," Gaffga and colleagues report. "Because only a portion of salmonella infections are laboratory confirmed, it is likely that thousands of additional unreported infections occurred in association with this outbreak."
Salmonella and Mail-Order Poultry
How could just one hatchery spread so much illness?
"Hatchery C" produces 4 million birds a year. It ships them to all 50 states. Many of the infected chicks and ducklings are given to children as Easter gifts. They are sold in feed stores and by direct mail. In states where it's not illegal, some of the baby birds are dyed to make them more attractive to children.
"During the spring, which is the peak shipping season, Hatchery C ships an estimated 25,000 birds in one week," Gaffga and colleagues note.
It's a big business. Some 20 U.S. mail-order hatcheries ship about 50 million live chickens, ducklings, and other poultry each year. In the first half of 2009, the U.S. Postal Service shipped about 1.2 million pounds of packages containing live poultry. These cardboard boxes carry up to 100 birds.
Other U.S. hatcheries have been linked to salmonella outbreaks. Even the CDC and the USDA can't always tell where shipped chicks and ducklings came from. That's because when one hatchery can't fill an order, another hatchery "drop ships" the order under the original label and invoice.
Salmonella infection is common in poultry. Infected birds don't always have symptoms and don't always shed salmonella bacteria. This makes it impossible to check individual birds for signs of infection. And poultry vaccines do not eliminate salmonella from a hatchery.
The USDA can ask hatcheries to clean up their acts, but they can't make them do it. Hatcheries are asked to follow the USDA's "National Poultry Improvement Program," as egg farms are required to do. For hatcheries, compliance is voluntary.
According to Gaffga and colleagues, Hatchery C has tried to clean up its act. They did this by "replacing, updating, and sealing old equipment and floors; changing airflow within the facility; implementing a quaternary ammonium egg-cleaning procedure; improving biosecurity; conducting routine biologic surveillance for salmonella on the hatchery premises; and contracting with a private company to develop [a poultry vaccine]."
But between 2008 and 2009, 14 of 200 environmental samples from the hatchery still tested positive for the outbreak strain of salmonella.