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Four Multistate Outbreaks of Human Salmonella Infections Linked to Live Poultry in Backyard Flocks (Final Update)

Posted September 24, 2015 4:15 PM ET


These investigations are over. However, live poultry, including those kept in backyard flocks, remain an important cause of human Salmonella infections in the United States. More information about Salmonella from live poultry and the steps people can take to reduce their risk of infection is available.

Highlights

  • Read the Advice to Backyard Flock Owners »
  • These investigations are over. However, live poultry, including those kept in backyard flocks, remain an important source of human Salmonella infections in the United States.
  • Backyard flock owners should take steps to protect themselves and their families:
    • Always wash hands thoroughly with soap and water right after touching live poultry or anything in the area where the birds live and roam.
    • Do not let live poultry inside the house.
    • Learn about additional recommendations to prevent Salmonella infections from live poultry. These recommendations are important and apply to all live poultry, regardless of the age of the birds or where they were purchased.
  • Mail-order hatcheries, agricultural feed stores, and others that sell or display chicks, ducklings, and other live poultry should provide health-related information to owners and potential purchasers of these birds prior to the point of purchase. This should include information about the risk of acquiring a Salmonella infection from contact with live poultry.
  • CDC, public health, veterinary, and agriculture officials in many states and the U.S. Department of Agriculture's Animal and Plant Health Inspection Service (USDA-APHIS) investigated four multistate outbreaks of human Salmonella infections linked to contact with live poultry.
  • 252 people infected with the outbreak strains of Salmonella were reported from 43 states.
    • 63 ill people were hospitalized, and no deaths were reported.
  • Epidemiologic, laboratory, and traceback findings linked these four outbreaks of human Salmonella infections to contact with chicks, ducklings, and other live poultry from multiple hatcheries.
    • 146 (80%) of the 183 ill people who were interviewed reported contact with live poultry in the week before their illness began.
  • CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory conducted antibiotic resistance testing on Salmonella isolates collected from 20 ill people infected with one of the outbreak strains.
    • 19 (95%) isolates were susceptible to all antibiotics tested on the NARMS panel.
    • One (5%) isolate was resistant to sulfisoxazole.

Outbreak Summaries

Introduction

CDC collaborated with public health, veterinary, and agriculture officials in many states and with the U.S. Department of Agriculture's Animal and Plant Health Inspection Service (USDA-APHIS) to investigate four multistate outbreaks of human Salmonella infections. Results from these investigations indicated that contact with live poultry was the likely source of these outbreaks.

Public health investigators used the PulseNet system to identify illnesses that were part of these outbreaks. PulseNet is the national subtyping network of public health and food regulatory agency laboratories coordinated by CDC. DNA "fingerprinting" is performed on Salmonella bacteria isolated from ill people by using a technique called pulsed-field gel electrophoresis, or PFGE. PulseNet manages a national database of these DNA fingerprints to identify possible outbreaks. A total of 10 DNA fingerprints (“outbreak strains”) were included in these investigations.

In the four outbreaks, 252 people infected with one of the outbreak strains of Salmonella were reported from 43 states between January 3, 2015 and September 6, 2015.

Investigation of the Outbreaks

In interviews, ill people answered questions about contact with animals and foods consumed during the week before becoming ill; 146 (80%) of the 183 ill people interviewed reported contact with live poultry (e.g., chicks, chickens, ducks, ducklings) before becoming ill. Ninety-four ill people who had purchase records available reported purchasing live baby poultry from 41 different suppliers, including feed supply stores, Co-Ops, “flea markets”, friends, and hatcheries in multiple states. Ill people reported purchasing live poultry for backyard flocks to produce eggs or meat or to keep as pets. Twenty-eight (41%) of 69 ill people with complete questionnaires reported keeping baby poultry indoors, 39 (57%) of 69 reported holding or snuggling baby poultry, and 4 (6%) of 69 reported kissing baby poultry. These behaviors increase a person’s risk of a Salmonella infection.

CDC's National Antibiotic Resistance Monitoring System (NARMS) laboratory conducted antibiotic resistance testing on clinical isolates collected from 20 people infected with one of the outbreak strains. One (5%) isolate was resistant to sulfisoxazole, and 19 (95%) isolates were susceptible to all antibiotics tested on the NARMS panel.

Final summaries of the four outbreak investigations are provided below.

Outbreak 1: Salmonella Enteritidis Investigation

Sixty-five people infected with the outbreak strains of Salmonella Enteritidis were reported from 18 states. The number of people in each state was as follows: Arizona (1), California (3), Georgia (1), Indiana (1), Maine (1), Minnesota (7), New Hampshire (3), Ohio (20), Oklahoma (1), Oregon (3), South Carolina (2), Tennessee (1), Texas (2), Utah (5), Vermont (2), Virginia (7), Washington (4), and Wyoming (1).

Illness onset dates ranged from January 3, 2015 to August 4, 2015. Ill people ranged in age from younger than one year to 81, and the median age was 32. Fifty-two percent of ill people were male. Among 50 ill people with available information, 12 (24%) were hospitalized, and no deaths were reported.

Outbreak 2: Salmonella Hadar Investigation

Seventy-eight people infected with the outbreak strains of Salmonella Hadar were reported from 30 states. The number of people in each state was as follows: Arizona (2), Arkansas (2), California (3), Colorado (1), Delaware (2), Iowa (1), Kentucky (1), Louisiana (2), Maine (1), Maryland (3), Massachusetts (1), Michigan (1), Minnesota (1), Missouri (1), Montana (4), North Carolina (2), New Jersey (2), New Mexico (1), New York (3), Ohio (3), Oregon (5), Pennsylvania (11), South Carolina (4), South Dakota (2), Texas (2), Virginia (8), Washington (4), West Virginia (1), Wisconsin (1), Wyoming (3).

Illness onset dates ranged from February 22, 2015 to August 26, 2015. Ill people ranged in age from younger than one year to 89, and the median age was 39. Fifty-two percent of ill people were female. Among 51 ill people with available information, 29 (57 %) were hospitalized, and no deaths were reported.

Outbreak 3: Salmonella Indiana Investigation

Sixty-eight people infected with the outbreak strains of Salmonella Indiana were reported from 18 states. The number of people in each state was as follows: Alabama (17), Arkansas (2), California (5), Colorado (1), Georgia (2), Idaho (1), Maryland (1), Mississippi (13), Nevada (4), New Jersey (2), New Mexico (1), New York (8), North Carolina (1), Oregon (1), Pennsylvania (1), South Carolina (6), Tennessee (1), and Texas (1).

Illness onset dates ranged from January 6, 2015 to September 6, 2015. Ill people ranged in age from younger than one year to 89, and the median age was 2. Fifty-three percent of ill people were female. Among 39 ill people with available information, 12 (31 %) were hospitalized, and no deaths were reported.

Outbreak 4: Salmonella Muenchen and Salmonella Muenster Investigation

Forty-one people infected with the outbreak strains of Salmonella Muenchen or Salmonella Muenster were reported from 19 states. The number of people in each state was as follows: Alabama (3), California (1), Georgia (1), Hawaii (1), Illinois (1), Indiana (4), Kentucky (4), Michigan (5), New Jersey (2), New York (1), North Carolina (2), Ohio (3), Pennsylvania (1), Tennessee (5), Utah (1), Virginia (1), Washington (1), West Virginia (3), and Wisconsin (1).

Illness onset dates ranged from February 26, 2015 to August 10, 2015. Ill people ranged in age from younger than one year to 77, and the median age was 18. Fifty-six percent of ill people were male. Among 30 ill people with available information, 10 (33 %) were hospitalized, and no deaths were reported.

July 30, 2015

Investigation Update

CDC continues to collaborate with public health, veterinary, and agriculture officials in many states and with the U.S. Department of Agriculture's Animal and Plant Health Inspection Service (USDA-APHIS) to investigate several multistate outbreaks of human Salmonella infections linked to contact with live poultry. Since the initial announcement on July 1, 2015, an additional serotype was identified. A total of 10 DNA fingerprints (outbreak strains) are now included in these outbreak investigations.

In the four outbreaks, a total of 218 people infected with one of the outbreak strains of Salmonella have been reported from 41 states as of July 29, 2015. Illnesses that occurred after July 4, 2015, 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 4 weeks.

In ongoing interviews, ill people answered questions about contact with animals and foods consumed during the week before becoming ill; to date, 117 (84%) of the 140 ill people interviewed reported contact with live poultry (e.g., chicks, chickens, ducks, ducklings) before becoming ill. Ninety-four ill people who had purchase records available reported purchasing live poultry from 32 different suppliers including feed supply stores, Co-Ops, “flea markets”, friends, and hatcheries in multiple states. Ill people reported purchasing live poultry for backyard flocks to produce eggs or meat, or to keep as pets. Many ill people in these outbreaks reported bringing the live baby poultry into their homes, and others reported kissing or cuddling with the live poultry. These behaviors increase a person’s risk of a Salmonella infection.

To date, CDC's NARMS laboratory conducted antibiotic resistance testing on clinical isolates collected from 16 ill people infected with one of the outbreak strains; all isolates were susceptible to all antibiotics tested on the NARMS panel. CDC’s NARMS laboratory continues to conduct antibiotic resistance testing on additional clinical isolates. Results will be reported when they become available.

CDC and state and local public health partners are continuing laboratory surveillance through PulseNet to identify additional ill people and to interview them. CDC will provide updates when more information is available. Summaries of each of the four outbreak investigations are provided below.

Outbreak 1: Salmonella Enteritidis Investigation

Since the initial announcement on July 1, 2015, 10 additional people infected with the outbreak strains of Salmonella Enteritidis have been reported from 5 states as of July 29, 2015. The additional ill people have been reported from the following states: California (2), New Hampshire (2), Ohio (4), Virginia (1), and Washington (1).

Among the people who reported the date they became ill, illnesses began between January 5, 2015 and July 4, 2015. Ill people range in age from younger than one year to 74, and the median age is 21. Forty-eight percent of ill people are female. Among 30 ill people with available information, 7 (23%) have been hospitalized. No deaths have been reported.

Outbreak 2: Salmonella Hadar Investigation

Since the initial announcement on July 1, 2015, 5 additional people infected with the outbreak strain of Salmonella Hadar have been reported from 4 states as of July 29, 2015. The additional ill people have been reported from the following states: California (2), New York (1), Virginia (1), and Washington (1).

Among the people who reported the date they became ill, illnesses began between February 24, 2015 and July 6, 2015. Ill people range in age from younger than one year to 89, and the median age is 38. Fifty-three percent of ill people are female. Among 48 ill people with available information, 26 (54%) have been hospitalized. No deaths have been reported.

Outbreak 3: Salmonella Indiana Investigation

Since the initial announcement on July 1, 2015, 5 additional people infected with the outbreak strains of Salmonella Indiana have been reported from 4 states as of July 29, 2015. The additional ill people have been reported from the following states: California (1), New York (2), Pennsylvania (1), and South Carolina (1).

Among the people who reported the date they became ill, illnesses began between January 5, 2015 and June 24, 2015. Ill people range in age from younger than one year to 82, and the median age is 2. Fifty-three percent of ill people are female. Among 30 ill people with available information, 9 (30%) have been hospitalized. No deaths have been reported.

Outbreak 4: Salmonella Muenchen or Salmonella Muenster Investigation

Since the initial announcement on July 1, 2015, 17 additional people have become infected with the outbreak strains of Salmonella Muenchen or Salmonella Muenster from 12 states as of July 29, 2015. The number of ill people identified in each state is as follows: Alabama (2), Georgia (1), Illinois (1), Kentucky (1), Michigan (3), North Carolina (2), New Jersey (2), New York (1), Virginia (1), Washington (1), Wisconsin (1), and West Virginia (1). Two DNA fingerprint (outbreak strains) are included in this investigation.

Among the people who reported the date they became ill, illnesses began between and March 8, 2015 and July 11, 2015. Ill people range in age from younger than one year to 77, and the median age is 15. Forty-seven percent of ill people are female. Among 24 ill people with available information, 8 (33%) have been hospitalized. No deaths have been reported.

Initial Announcement

July 1, 2015

CDC is collaborating with public health, veterinary, and agriculture officials in many states and with the U.S. Department of Agriculture's Animal and Plant Health Inspection Service (USDA-APHIS) to investigate four multistate outbreaks of human Salmonella infections linked to contact with live poultry.

Public health investigators are using the PulseNet system to identify illnesses that may be part of these outbreaks. PulseNet is the national subtyping network of public health and food regulatory agency laboratories coordinated by CDC. DNA "fingerprinting" is performed on Salmonella bacteria isolated from ill people by using a technique called pulsed-field gel electrophoresis, or PFGE. PulseNet manages a national database of these DNA fingerprints to identify possible outbreaks. A total of nine DNA fingerprints (outbreak strains) are included in these four outbreak investigations.

In the four outbreaks, a total of 181 people infected with the outbreak strains of Salmonella have been reported from 40 states as of June 29, 2015. The number of ill people identified in each state is as follows: Alabama (17), Arizona (3), Arkansas (4), California (3), Colorado (2), Delaware (2), Georgia (4), Indiana (3), Iowa (1), Kentucky (4), Louisiana (2), Maine (2), Maryland (4), Massachusetts (1), Michigan (3), Minnesota (6), Mississippi (13), Missouri (1), Montana (3), Nevada (2), New Hampshire (1), New Jersey (3), New Mexico (2), New York (6), North Carolina (3), Ohio (15), Oklahoma (1), Oregon (5), Pennsylvania (12), South Carolina (10), South Dakota (2), Tennessee (6), Texas (5), Utah (4), Vermont (2), Virginia (11), Washington (6), West Virginia (2), Wisconsin (1), and Wyoming (4).

These outbreaks can be illustrated with a chart showing the number of people who became ill each day. This chart is called an epidemic curve or epi curve. Illnesses that occurred after June 1, 2015, 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 4 weeks. Please see the Timeline for Reporting Cases of Salmonella Infection for more details.

In interviews, ill people answered questions about contact with animals and foods consumed during the week before becoming ill; 82 (86%) of the 95 ill people interviewed reported contact with live poultry (e.g., chicks, chickens, ducks, ducklings) before becoming ill. Sixty-four ill people who had purchase records available reported purchasing live baby poultry from 17 different feed supply stores and hatcheries in multiple states. Ill people reported purchasing live poultry for backyard flocks to produce eggs or meat, or to keep as pets. Many ill people in these outbreaks reported bringing the live poultry into their homes, and others reported kissing or cuddling with the live poultry. These behaviors increase a person’s risk of a Salmonella infection.

Preliminary findings of multiple traceback investigations of live baby poultry from homes of ill people have identified multiple hatcheries as the source of chicks and ducklings. These investigations are ongoing.

The National Antimicrobial Resistance Monitoring System (NARMS) is a U.S. public health surveillance system that tracks antibiotic resistance in foodborne and other enteric bacteria found in people, raw meat and poultry, and food-producing animals. NARMS is a partnership among the CDC, the U.S. Food and Drug Administration (FDA), the U.S. Department of Agriculture (USDA), and state and local health departments.

The NARMS human surveillance program at CDC monitors antibiotic resistance in Salmonella and other bacteria isolated from clinical specimens submitted to NARMS by public health laboratories. CDC's NARMS laboratory conducted antibiotic resistance testing on clinical isolates collected from seven ill people infected with one of the outbreak strains; all seven isolates were susceptible to all antibiotics tested on the NARMS panel. CDC's NARMS laboratory continues to conduct antibiotic resistance testing on additional clinical isolates collected from ill persons infected with the outbreak strains. Results will be reported when they become available.

CDC and state and local public health partners are continuing laboratory surveillance through PulseNet to identify additional ill people and to interview them. CDC will provide updates when more information is available. Summaries of each of the four outbreak investigations are provided below.

Outbreak 1: Salmonella Enteritidis Investigation

As of June 29, 2015, 40 people infected with the outbreak strains of Salmonella Enteritidis have been reported from 16 states. The number of ill people identified in each state is as follows: Arizona (1), Georgia (2), Indiana (1), Maine (1), Minnesota (5), New Hampshire (1), Ohio (10), Oklahoma (1), South Carolina (2), Tennessee (1), Texas (2), Utah (3), Vermont (2), Virginia (4), Washington (3), and Wyoming (1). Two DNA fingerprints (outbreak strains) are included in this investigation. 

Among the people who reported the date they became ill, illnesses began between January 6, 2015 and June 13, 2015. Ill people range in age from younger than one year to 81 years, and the median age is 41. Fifty-two percent of ill people are female. Among the 14 ill people with available information, 3 (21%) have been hospitalized. No deaths have been reported.

Outbreak 2: Salmonella Hadar Investigation

As of June 29, 2015, 69 people infected with the outbreak strains of Salmonella Hadar have been reported from 30 states. The number of ill people identified in each state is as follows: Arizona (2), Arkansas (2), California (1), Colorado (1), Delaware (2), Iowa (1), Kentucky (1), Louisiana (2), Maine (1), Maryland (3), Massachusetts (1), Michigan (1), Minnesota (1), Missouri (1), Montana (3), New Jersey (2), New Mexico (1), New York (1), North Carolina (2), Ohio (3), Oregon (4), Pennsylvania (11), South Carolina (3), South Dakota (2), Texas (2), Virginia (7), Washington (3), Wisconsin (1), West Virginia (1), and Wyoming (3). One DNA fingerprint (outbreak strain) is included in this investigation.

Among the people who reported the date they became ill, illnesses began between February 24, 2015 and June 11, 2015. Ill people range in age from younger than one year to 89 years, and the median age is 37. Fifty-one percent of ill people are female. Among 30 ill people with available information, 19 (63%) have been hospitalized. No deaths have been reported.

Outbreak 3: Salmonella Indiana Investigation

As of June 29, 2015, 56 people infected with the outbreak strains of Salmonella Indiana have been reported from 16 states. The number of ill people identified in each state is as follows: Alabama (17), Arkansas (2), California (2), Colorado (1), Georgia (2), Maryland (1), Mississippi (13), Nevada (2), New Jersey (1), New Mexico (1), New York (5), North Carolina (1), Oregon (1), South Carolina (5), Tennessee (1), and Texas (1).  Five DNA fingerprints (outbreak strains) are included in this investigation.

Among the people who reported the date they became ill, illnesses began between February 20, 2015 and June 11, 2015. Ill people range in age from younger than one year to 82 years, and the median age is 2. Fifty-two percent of ill people are female. Among the 28 ill people with available information, nine (32%) have been hospitalized. No deaths have been reported.

Outbreak 4: Salmonella Muenchen Investigation

As of June 26, 2015, 16 people infected with the outbreak strains of Salmonella Muenchen have been reported from eight states. The number of ill people identified in each state is as follows: Indiana (2), Kentucky (3), Michigan (2), Ohio (2), Pennsylvania (1), Tennessee (4), Utah (1), and West Virginia (1). One DNA fingerprint (outbreak strain) is included in this investigation.

Among the people who reported the date they became ill, illnesses began between and April 4, 2015 and June 5, 2015. Ill people range in age from younger than one year to 75 years, and the median age is 21. Sixty-three percent of ill people are female. Among eight ill people with available information, two (25%) have been hospitalized. No deaths have been reported.

At A Glance

  • Case Count: 252
  • States: 43
  • Deaths: 0
  • Hospitalizations: 63
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