2010 Salmonella Outbreak Linked to Frozen Rodents

Posted August 2, 2010

Outbreak Summary

CDC is collaborating with public health officials in many states and the U.S. Food and Drug Administration (FDA) to investigate a multistate outbreak of Salmonella infection, serotype I 4,[5],12:i:-. Investigators are using DNA analysis of Salmonella bacteria obtained through diagnostic testing to identify cases of illness that may be part of this outbreak.

As of July 29, 2010, a total of 34 individuals infected with a matching strain of Salmonella serotype I 4,[5],12:i:- have been reported from 17 states since January 1, 2010. The number of ill persons identified in each state with this strain is as follows: AL (1), AZ (1), CO (1), GA (7), IA (1), IL (3), MA (3), MI (1), MO (3), NC (3), NV (1), NY (2), SC (1), TN (1), VA (1), WI (3), and WY (1).

Among the persons with reported illness onset dates available, illnesses began between December 4, 2009, and June 9, 2010. Infected individuals range in age from <1 to 57 years old and the median age is 12 years. Fifty-three percent of patients are male. Among the 17 patients with available information, 1 (6%) was hospitalized. As of July 29, 2010, no deaths attributed to this infection have been reported.

The outbreak can be visually described with a chart showing the number of persons who became ill each day. This chart is called an epidemic curve or epi curve. Illnesses that occurred after June 14, 2010, might not yet be reported due to the time it takes between when a person becomes ill and when the illness is reported. This takes an average of 2 to 3 weeks. Please see the Timeline for Reporting Cases of Salmonella Infection.

Investigation of the Outbreak

CDC and public health officials in multiple states are conducting an epidemiologic study. Preliminary analysis of this study has suggested an association with frozen rodents used for reptile feed. Ill persons (61 percent) were significantly more likely than well persons (0 percent) to report any exposure to rodents in the week before illness. Additionally, ill persons (26 percent) were significantly more likely than well persons (0 percent) to report using frozen rodents for reptile feed in the week before illness. An environmental investigation was conducted by the FDA, and culture of samples collected yielded Salmonella that matched the human outbreak strain.

Although referred to differently in the United States and United Kingdom, the strain in the U.S. investigation is indistinguishable from the strain that caused an outbreak in the United Kingdom in 2009. The outbreak investigation by the Health Protection Agency of the United Kingdom implicated frozen mice imported from the United States as food for pet reptiles as the source of human illness.

On July 23, 2010, the company producing the frozen rodents announced a recall.

Advice to Consumers

• Wash your hands thoroughly with soap and water immediately after handling frozen rodents used as food for reptiles, or anything in the area where they are stored, thawed, prepared, and fed to reptiles.
• Wash your hands thoroughly with soap and water immediately after handling live rodents and reptiles, or anything in the area where they live and roam.
• Running water and soap are best. Use hand sanitizers if running water and soap are not available. Be sure to wash your hands with soap and water as soon as a sink is available.
• Keep frozen rodents away from areas where food and drink are stored, prepared, served, or consumed.
• Avoid using microwave ovens or kitchen utensils used for human food to thaw frozen rodents used for reptile feed. Any kitchen surfaces that come in contact with frozen rodents should be disinfected afterwards.
• Do not let children younger than 5 years of age or people with weakened immune systems handle frozen rodents.
• Use soap or a disinfectant to thoroughly clean any surfaces that have been in contact with frozen rodents. Children older than 5 years old should perform this task only under adult supervision.
• Recalled frozen rodents used as food for reptiles may still be in stores and in consumers’ homes, including in the freezer. Any recalled product should be thrown away to prevent Salmonella infections in humans, pets, or other animals. This product should be disposed of in a closed plastic bag and placed in a sealed trash can to prevent people or animals, including wild animals, from eating it.

General Resources

• General Information: Salmonella

Additional Information

• Biggers & Callaham, LLC DBA Mice Direct Recalls Frozen Reptile Feed Because of Possible Health Risk
• Reptiles, Amphibians, and Salmonella

Final Case Count Map

Persons infected with the outbreak strain of Salmonella I 4,[5],12:i:-, by state, as of July 29, 2010 (n=34)

As of July 29, 2010, a total of 34 individuals infected with a matching strain of Salmonella serotype I 4,[5],12:i:- have been reported from 17 states since January 1, 2010. The number of ill persons identified in each state with this strain is as follows: AL (1), AZ (1), CO (1), GA (7), IA (1), IL (3), MA (3), MI (1), MO (3), NC (3), NV (1), NY (2), SC (1), TN (1), VA (1), WI (3), and WY (1).

Final Epi Curve

This outbreak can be visually described with a chart showing the number of persons who became ill each day. This chart is called an epi curve. Please see the Timeline for Reporting Cases of Salmonella Infection for more details on the reporting process.

Persons infected with the outbreak strain of Salmonella I 4,[5],12:i:-, by date of illness onset*

*n=34 for whom information was reported as of July 29, 2010. Some illness onset dates have been estimated from other reported information.