Multistate Outbreak of Human Salmonella Typhimurium Infections Linked to Pet Hedgehogs (Final Update)

Introduction

CDC collaborated with public health and agriculture officials in many states and the U.S. Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service, Animal Care, to investigate an outbreak of human Salmonella Typhimurium infections linked to contact with pet hedgehogs purchased from multiple sources in different states.

Public health investigators used the PulseNet system to identify cases of illness that were part of this outbreak. In PulseNet, the national subtyping network of public health and food regulatory agency laboratories coordinated by CDC, DNA “fingerprints” of Salmonella bacteria are obtained through diagnostic testing with pulsed-field gel electrophoresis, or PFGE, to identify cases of illness that were part of this outbreak.

A total of 26 persons infected with the outbreak strain of Salmonella Typhimurium were reported from 12 states: Alabama (1), Idaho (1), Illinois (1), Indiana (1), Louisiana (1), Michigan (3), Minnesota (3), Missouri (1), New Hampshire (1), Ohio (5), Oregon (1), and Washington (7).

Among 26 persons for whom information was available, illness onset dates ranged from December 26, 2011 to April 8, 2013. Ill persons ranged in age from less than 1 year to 91 years, with a median age of 15 years. Thirty-five percent of ill persons were children 10 years of age or younger. Fifty-eight percent of ill persons were female. Among 23 persons with available information, 8 (35%) reported being hospitalized. One death associated with Salmonella infection was reported in Washington.

Investigation of the Outbreak

Epidemiologic, laboratory, and traceback investigations conducted by officials in local, state, and federal public health, agriculture, and regulatory agencies linked this outbreak to contact with pet hedgehogs. During interviews, ill persons answered questions about contact with animals and foods consumed during the week before becoming ill. Twenty (80%) of 25 ill persons interviewed reported contact with pet hedgehogs or their environments before becoming ill. Some ill persons specifically mentioned contact with African Pygmy hedgehogs.

State health department laboratories and the USDA National Veterinary Services Laboratory in Ames, Iowa tested hedgehog and environmental samples collected from ill persons’ homes. Several fecal samples from pet hedgehogs and environmental samples from areas where pet hedgehogs lived or were bathed in patient households yielded the outbreak strain of Salmonella Typhimurium.

Findings of multiple traceback investigations of pet hedgehogs from homes of ill persons identified multiple sources in different states as the source of the hedgehogs. Among 17 ill persons with available purchase information, hedgehogs were reportedly purchased from the following sources: 10 (59%) were purchased from USDA-licensed breeders, 1 (5%) was purchased from a USDA-licensed pet store, 3 (18%) were purchased from breeders that were either not USDA-licensed or their licensure status was unknown, and 3 (18%) were purchased from private individuals. A single source of the hedgehogs was not identified.

At this time, no further updates are planned for this outbreak investigation. However, contact with hedgehogs continues to be a source of human Salmonella infections. You should know how to protect yourself and your family from illness spread between people and hedgehogs. Hedgehogs can be carrying Salmonella bacteria but appear healthy and clean and show no signs of illness. It is very important to wash your hands thoroughly with soap and water right after touching hedgehogs or anything in the area where they live and roam. Adults should supervise hand washing for young children.

Salmonella is an important cause of human illness in the United States. More information about Salmonella and steps people can take to reduce their risk of infection can be found on the CDC Salmonella Web Page.

June 14, 2013

Final Case Count Update

A total of 26 persons infected with the outbreak strain of Salmonella Typhimurium were reported from 12 states. Three new ill persons from Louisiana, Missouri, and New Hampshire were reported since the last case count update on April 16, 2013.

Among 26 persons for whom information was available, illness onset dates ranged from December 26, 2011 to April 8, 2013. Ill persons ranged in age from less than 1 year to 91 years, with a median age of 15 years. Thirty-five percent of ill persons were children 10 years of age or younger. Fifty-eight percent of ill persons were female. Among 23 persons with available information, 8 (35%) reported being hospitalized. One death associated with Salmonella infection was reported in Washington.

April 16, 2013

Case Count Update

A total of 23 persons infected with the outbreak strain of Salmonella Typhimurium have been reported from 9 states. Since the last update, 3 new cases have been reported from Idaho (1) and Ohio (2).

Among the persons who reported the date they became ill, illnesses began between December 26, 2011 and March 5, 2013. Ill persons range in age from less than 1 year to 91 years, with a median age of 14 years. Thirty-nine percent of ill persons are 10 years of age or younger. Sixty-one percent of ill persons are female. Among 20 ill persons with available information, 7 (35%) have been hospitalized. One death associated with Salmonella infection has been reported in Washington.

Illnesses that occurred after March 19, 2013 might not be reported yet due to the time it takes between when a person becomes ill and when the illness is reported.

Investigation Update

In interviews, ill persons answered questions about contact with animals and foods consumed during the week before becoming ill. Nineteen (86%) of 22 ill persons interviewed reported contact with pet hedgehogs or their environments before becoming ill. Investigations are ongoing to determine the type and source of hedgehogs that might be linked with illness. Ill persons with available purchase information reported purchasing pet hedgehogs from multiple breeders in several states.

The United States Department of Agriculture Animal and Plant Health Inspection Service (USDA-APHIS) Animal Care is currently assisting CDC to identify the sources of hedgehogs linked to ill persons. State health departments have also tested additional environmental and hedgehog samples collected from ill persons’ homes. The outbreak strain of Salmonella Typhimurium was isolated from Illinois environmental samples of a hedgehog’s wheel, ramp, feed area, and bedding as well as from the pet hedgehog’s feces.  The outbreak strain was also isolated from an Ohio pet hedgehog’s feces.

January 31, 2013

Case Count Update

A total of 20 persons infected with the outbreak strain of Salmonella Typhimurium have been reported from 8 states. Since the last update, 4 cases have been reported from Illinois (1), Ohio (1), Minnesota (1), and Washington (1).

Among the persons who reported the date they became ill, illnesses began between December 26, 2011 and December 31, 2012. Ill persons range in age from less than 1 year to 91 years, with a median age of 13 years. Forty-five percent of ill persons are 10 years of age or younger. Fifty-five percent of ill persons are female. Among 13 ill persons with available information, 4 (31%) have been hospitalized. One death associated with Salmonella infection has been reported in Washington.

Illnesses that occurred after January 4, 2013 might not be reported yet due to the time it takes between when a person becomes ill and when the illness is reported.

Investigation Update

In interviews, ill persons answered questions about contact with animals and foods consumed during the week before becoming ill. Fourteen (93%) of 15 ill persons interviewed reported contact with hedgehogs or their environments before becoming ill. Some ill persons specifically mentioned contact with African Pygmy hedgehogs. Investigations are ongoing to determine the type and source of hedgehogs that might be linked with illness. Ill persons with available purchase information reported purchasing pet hedgehogs from multiple breeders in several states.

The United States Department of Agriculture Animal and Plant Health Inspection Service (USDA-APHIS) Animal Care is currently conducting traceback investigations of hedgehogs purchased from USDA-licensed breeders linked to ill persons. In addition, state health departments have tested environmental and hedgehog samples collected from ill persons’ homes. The outbreak strain of Salmonella Typhimurium was isolated from a Minnesota environmental sample of a container and sink in which a pet hedgehog was bathed. The outbreak strain was also isolated from a second hedgehog purchased after the first hedgehog and case-patient in Minnesota became ill.

January 9, 2013

Case Count Update

A total of 16 persons infected with the outbreak strain of Salmonella Typhimurium have been reported from 7 states. Since the last update, two cases have been reported from Oregon (1) and Washington (1).

Among the persons who reported the date they became ill, illnesses began between December 26, 2011 and November 2, 2012. Ill persons range in age from less than 1 year to 62 years, and 50% of ill persons are 10 years of age or younger. Sixty-four percent of ill persons are female. Among 10 ill persons with available information, 3 (30%) have been hospitalized. No deaths have been reported.

Illnesses that occurred after December 17, 2012 might not be reported yet due to the time it takes between when a person becomes ill and when the illness is reported.

Initial Announcement

September 6, 2012

CDC is collaborating with public health and agriculture officials in many states and the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service, Animal Care Program (USDA-APHIS-AC) to investigate an outbreak of human Salmonella Typhimurium infections linked to hedgehogs purchased from multiple breeders. Public health investigators are using the PulseNet system to identify cases of illness that may be part of this outbreak. In PulseNet, the national subtyping network of public health and food regulatory agency laboratories coordinated by CDC, DNA “fingerprints” of Salmonella bacteria are obtained through diagnostic testing with pulsed-field gel electrophoresis, or PFGE.

These outbreaks 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 August 14, 2012 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 Salmonella Outbreak Investigations: Timeline for Reporting Cases for more details.

Contact with hedgehogs can be a source of human Salmonella infections. Salmonella germs are shed in their droppings and can easily contaminate their bodies and anything in areas where these animals live and roam. You should always wash hands thoroughly with soap and water right after touching hedgehogs or anything in the area where they live and roam. Adults should supervise hand washing for young children.

Investigation of the Outbreak

As of September 5, 2012, a total of 14 persons infected with the outbreak strain of Salmonella Typhimurium have been reported from 6 states. The number of ill persons identified in each state is as follows: Alabama (1), Indiana (1), Michigan (3), Minnesota (2), Ohio (2), and Washington (5). The outbreak strain has been rarely seen in the past.

Among the persons who reported the date they became ill, illnesses began between December 26, 2011 and August 13, 2012. Infected individuals range in age from less than 1 year to 62 years, and 50% of ill persons are 10 years of age or younger. Sixty-two percent of ill persons are female. Among 10 ill persons with available information, 3 (30%) have been hospitalized. No deaths have been reported.

In interviews, ill persons answered questions about contact with animals and foods consumed during the week before becoming ill. Ten (100%) of 10 ill persons interviewed reported contact with hedgehogs or their environments before becoming ill. Some ill persons specifically mentioned contact with African Pygmy hedgehogs. Investigations are ongoing to determine the type and source of hedgehogs that might be linked with illness. Ill persons with available purchase information reported purchasing pet hedgehogs from multiple breeders in several states.

USDA-APHIS-AC is currently conducting traceback investigations of hedgehogs purchased from USDA-licensed breeders linked to ill persons. In addition, state health departments have tested environmental and hedgehog samples collected from ill persons’ homes. Two environmental samples from areas where hedgehogs lived or were bathed in patient households yielded the outbreak strain of Salmonella Typhimurium.