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Baby Chicks Crawling With Salmonella
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Not Just Peanut Butter: Two 2007-2008 Salmonella Outbreaks Traced to Chicks
Daniel J. DeNoon
Reviewed By Louise Chang, MD
Jan. 22, 2009 -- If you buy baby chicks as pets or for backyard flocks, you may very well get more than you bargained for: salmonella.
The CDC today reports two ongoing chains of salmonella infections, beginning in 2007, traced to baby chicks from 10 hatcheries in seven states. The outbreaks involved different strains of the same type of salmonella: Salmonella Montevideo.
Salmonella Montevideo is a different salmonella serotype from the Salmonella Typhimurium serotype causing the current outbreak traced to peanut butter products.
All told, 206 people were sickened in the Salmonella Montevideo outbreaks from 2007 to 2008; there have been no known deaths. Sixteen of the 129 people infected in 2007 were hospitalized. Investigation of the 2008 cases is still under way, CDC disease detective Umid Sharapov, MD, tells WebMD.
One of the strains has been around since it was first identified in 2004; it reappeared in 2005 and 2006 in chicks and ducklings at a New Mexico hatchery.
Is the outbreak still ongoing? That's a matter of definition. The 2004-2007 salmonella strain peaks in the spring and mainly affects children who get pet chicks and ducklings for Easter. The other 2007 strain peaked in the summer and mainly affected adults tending backyard flocks. Strains of both bugs -- with the same molecular fingerprints -- reappeared in 2008.
That, Sharapov confirms, means the problem may well be ongoing.
"We have surveillance systems in place. And our epidemiologists are looking at this and can detect outbreaks," Sharapov tells WebMD.
Most of the salmonella-carrying chicks came from two hatcheries, one in Iowa and one in New Mexico. Both hatcheries have undertaken steps to eliminate salmonella, including vaccinating chickens. But both hatcheries have had repeated salmonella problems in the past.
And the problem goes beyond these two sites. Many of the people who got sick ordered their chicks by mail. In the live-poultry industry, when one hatchery can't fill an order, another hatchery may ship chicks directly to the consumer under the name of the original hatchery. These so-called "drop shipments" make it hard to tell where chicks originated.
Also, hatcheries regularly receive eggs and chicks from various other hatcheries, further complicating trace-back studies.
Live chicks are sold to the public either by mail order or through feed stores.
"The chicks hatch in the spring and the hatcheries ship to customers via mail order," Sharapov says. "This is when the exposure occurs."
Salmonella, Chicks, and Kids
An analysis of the 2007 cases appears in today's issue of the CDC's Morbidity and Mortality weekly Report. The story began in June 2007, when the Minnesota Department of Health found that two people infected with Salmonella Montevideo had been exposed to chicks from the same Iowa hatchery. Then the North Dakota Department of Health detected the same salmonella strain in three siblings ages 1, 3, and 7. All three children were hospitalized for eight to 10 days.
That spurred a nationwide investigation by CDC and state health departments. In 2007, that investigation traced 65 cases of salmonella illness to chicks not only from the original Iowa hatchery, but from seven other hatcheries in four other states.
And investigators detected a second, simultaneous Salmonella Montevideo outbreak, also in live chicks but not related to the first outbreak. This outbreak was traced to a hatchery in New Mexico and a hatchery in Ohio. Salmonella with the same molecular fingerprint has been popping up every year since 2004.
The first outbreak peaked in the summer. Most of those infected were adults, although 40% of cases were in children and teens under age 18. Many of those infected had touched, snuggled, or cared for chicks. Of the 15 exposures with a known location, 15 occurred in a "farm setting."
The second outbreak peaked in the spring, around Easter. Seventy percent of those infected were children -- the median age at infection was 5. Most exposures occurred at home.
The CDC says parents should never give chicks as gifts to young children. The CDC also recommends:
SOURCES: CDC, Morbidity and Mortality Weekly Report, Jan. 23, 2009; vol 58: pp 25-29. Umid Sharapov, MD, medical epidemiologist, CDC.
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